Philosophy of science

"Those who have taken upon them to lay down the law of nature as a thing already searched out and understood, whether they have spoken in simple assurance or professional affectation, have therein done philosophy and the sciences great injury."

"Man, being the servant and interpreter of Nature, can do and understand so much and so much only as he has observed in fact or in thought of the course of nature. Beyond this he neither knows anything nor can do anything."

"The logic now in use serves rather to fix and give stability to the errors which have their foundation in commonly received notions than to help the search for truth. So it does more harm than good."

"There are and can be only two ways of searching into and discovering truth. The one flies from the senses and particulars to the most general axioms, and from these principles, the truth of which it takes for settled and immoveable, proceeds to judgment and to the discovery of middle axioms. And this way is now in fashion. The other derives axioms from the senses and particulars, rising by a gradual and unbroken ascent, so that it arrives at the most general axioms last of all. This is the true way, but as yet untried."

"Both ways set out from the senses and particulars, and rest in the highest generalities; but the difference between them is infinite. For the one just glances at experiment and particulars in passing, the other dwells duly and orderly among them. The one, again, begins at once by establishing certain abstract and useless generalities, the other rises by gradual steps to that which is prior and better known in the order of nature."

"There is a great difference between the Idols of the human mind and the Ideas of the divine. That is to say, between certain empty dogmas, and the true signatures and marks set upon the works of creation as they are found in nature."

"There can be no doubt that light consists of the motion of a certain substance. For if we examine its production we find that... when light is accumulated, say by concave mirrors, it has the property of combustion just as fire has, that is to say, it disunites the parts of bodies, which is assuredly a proof of motion, at least in the true philosophy, in which the causes of all natural effects are conceived as mechanical causes. Which in my judgment must be accomplished or all hope of ever understanding physics is renounced."

"[W]e offer this work as mathematical principles of philosophy. For all the difficulty of philosophy seems to consist in this, from the phenomena of motions to investigate the forces of Nature, and then from these forces to demonstrate the other phenomena."

"The only immediate utility of all sciences, is to teach us, how to control and regulate future events by their causes... And yet so imperfect are the ideas which we form concerning it, that it is impossible to give any just definition of cause, except what is drawn from something extraneous and foreign to it. Similar events are always conjoined with similar. Of this we have experience. Suitably to this experience, therefore, we may define a cause to be an object, followed by another, and where all the objects, similar to the first, are followed by objects similar to the second. Or in other words, where, if the first object had not been, the second never had existed. The appearance of the cause always conveys the mind, by a customary transition, to the idea of the effect. Of this also we have experience. We may, therefore, suitably to this experience, form another definition of cause; and call it, an object followed by another, and whose appearance always conveys the thought to that other. But though both these definitions be drawn from circumstances foreign to the cause, we cannot remedy this inconvenience, or attain any more perfect definition, which may point out that circumstance in the cause, which gives it a connexion with its effect. We have no idea of this connexion; nor even any distinct notion what it is we desire to know, when we endeavour at a conception of it."

"A judgment of observation can never rank as experience, without the law, that "whenever an event is observed, it is always referred to some antecedent, which it follows according to a universal rule." ...We cannot therefore study the nature of things a priori otherwise than by investigating the conditions and the universal (thought subjective) laws, under which alone such a cognition as experience (as to mere form) is possible..."

"Chemistry... Without this new order of phenomena the most important operations of terrestrial nature would be incomprehensible to us; and there is no other class of phenomena so intimate and so complex. Inert bodies can never appear so nearly like vital ones as when they produce in each other those rapid and profound perturbations which characterize chemical effects. ...the spirit of all theological and metaphysical philosophy consists in conceiving of all phenomena as analogous to the only one which is known by immediate consciousness—Life: and we can easily understand that the primitive method of philosophizing must have exerted a more powerful and obstinate dominion over chemical phenomena than any other, in the inorganic world.—We must consider, too, that direct and spontaneous observation must have been applied in the first place only to very complicated phenomena, such as vegetable combustions, fermentations, etc., the analysis of which now requires all the resources of our science: and that the most important chemical phenomena are produced only in artificial circumstances, which were long in being devised, and very difficult at first to institute. ...we can hardly imagine the difficulty there must have been, in the infancy of chemistry, in creating suitable subjects for observation: and we can not suppose that the ancient investigators of nature could have had energy and perseverance to discover the principal phenomena of the science if they had not been constantly stimulated by the unbounded hopes arising from their chimerical notions of the constitution of matter."

"Natural scientists believe that they free themselves from philosophy by ignoring or abusing it. They cannot, however, make any headway without thought, and for thought they need thought determinations. But they take these categories unreflectively from the common consciousness of so-called educated persons, which is dominated by relics of long obsolete philosophies, or from the little bit of philosophy compulsorily listened to at the university (which is not only fragmentary, but also a medley of views of people belonging to the most varied and mostly the worst schools) or from uncritical and unsystematic reading of philosophical writings of all kinds. Hence they are no less in bondage philosophy but unfortunately in most cases to the worst philosophy, and those who abuse philosophy most are slaves to precisely the worst vulgarized relics of the worst philosophies."

"Comte's work is the strongest embodied rebuke ever given to that form of theological intolerance which censures Positive Philosophy for pride of reason and lowness of morals. The imputation will not be dropped, and the enmity of the religious world to the book will not slacken... The theological world can not but hate a book which treats of theological belief as a transient state of the human mind. And again, the preachers and teachers, of all sects and schools, who keep to the ancient practice, once inevitable, of contemplating and judging of the universe from the point of view of their own minds, instead of having learned to take their stand out of themselves, investigating from the universe inward, and not from within outward, must necessarily think ill of a work which exposes the futility of their method, and the worthlessness of the results to which it leads. As M. Comte treats of theology and metaphysics as destined to pass away, theologians and metaphysicians must necessarily abhor, dread, and despise his work. ...We find ourselves suddenly living and moving in the midst of the universe,—as a part of it, and not as its aim and object. We find ourselves living, not under capricious and arbitrary conditions, unconnected with the constitution and movements of the whole, but under great, general, invariable laws, which operate on us as a part of the whole. ...We find here indications in passing of the evils we suffer from our low aims, our selfish passions, and our proud ignorance; and in contrast with them, animating displays of the beauty and glory of the everlasting laws, and of the sweet serenity, lofty courage, and noble resignation, that are the natural consequence of pursuits so pure, and aims so true, as those of Positive Philosophy. ...The law of progress is conspicuously at work throughout human history. The only field of progress is now that of Positive Philosophy, under whatever name it may be known to the real students of every sect; and therefore must that philosophy be favorable to those virtues whose repression would be incompatible with progress."

"The first process... in the effectual study of science must be one of simplification and reduction of previous investigation to a form in which the mind can grasp them. The results of this simplification may take the form of a purely mathematical formula or of a physical hypothesis."

"Mathematicians may flatter themselves that they possess new ideas which mere human language is yet unable to express. Let them make the effort to express these ideas in appropriate words without the aid of symbols, and if they succeed they will not only lay us laymen under a lasting obligation, but we venture to say, they will find themselves very much enlightened during the process, and will even be doubtful whether the ideas as expressed in symbols had ever quite found their way out of the equations of their minds."

"[T]he only thing that I believe that I am really fit for is the investigation of abstract truth, and the more abstract the better. If there is any science that I am capable of promoting, I think it is the science of science itself, the science of investigation, of method."

"I cannot perceive that the part which conceptions have in the operation of studying facts, has ever been overlooked or undervalued as Mr. Whewell supposes it has. No one ever disputed that in order to reason about anything we must have a conception of it; or that when we include a multitude of things under a general expression, there is implied in the expression a conception of something common to those things. But it by no means follows that the conception is necessarily pre-existent, or constructed by the mind out of its own materials. If the facts are rightly classed under the conception, it is because there is in the facts themselves something of which the conception is itself a copy; and which if we cannot directly perceive, it is because of the limited power of our organs, and not because the thing itself is not there. The conception itself is often obtained by abstraction from the very facts which, in Mr. Whewell's language, it is afterwards called in to connect. This Mr. Whewell himself admits, when he observes... how great a service would be rendered to the science of physiology by the philosopher "who should establish a precise, tenable, and consistent conception of life." Such a conception can only be abstracted from the phenomena of life itself; from the very facts which it is put in requisition to connect. In other cases... instead of collecting the conception from the very phenomena which we are attempting to colligate, we select it from among those which have been previously collected by abstraction from other facts. In the instance of Kepler's laws the latter was the case."

"It is such a case as this which gives color to the doctrine that the mind, in framing the descriptions, adds something of its own which it does not find in the facts. Yet it is a fact, surely, that the planet does describe an ellipse... knowing what an ellipse was, Kepler tried whether the observed places of the planet were consistent with such a path. He found they were so... But this fact, which Kepler did not add to, but found in the motions of the planet, namely, that it occupied in succession the various points in the circumference of a given ellipse, was the very fact, the separate parts of which had been separately observed; it was the sum of the different observations. It superadded nothing to the particular facts which it served to bind together: except... the knowledge that a resemblance existed between the planetary orbit and other ellipses..."

"When our conceptions are clear and distinct, when our facts are certain and sufficiently numerous, and when the conceptions, being suited to the nature of the facts, are applied to them so as to produce an exact and universal accordance, we attain knowledge of a precise and comprehensive kind, which we may term Science. And we apply this term... still more decidedly when, facts being thus included in exact and general propositions, such propositions are... included with equal rigour in propositions of a higher degree of generality; and these again in others of a still wider nature, so as to form a large and systematic whole."

"Ideas and Conceptions are... distinct elements of the scientific truths... [this is] proved beyond doubt, not only by considering that the discoveries never were made, nor could be made, till the right Conception was obtained, and by seeing how difficult it often was to obtain this element; but also, by seeing that the Idea and the Conception itself, as distinct from the Facts, was, in almost every science, the subject of long and obstinate controversies;—controversies which turned upon the possible relations of Ideas, much more than upon the actual relations of Facts. ...These controversies make up a large portion of the history of each science; a portion quite as important as the study of the facts; and a portion, at every stage of the science, quite as essential to the progress of truth."

"[T]he elliptical motion was not merely the sum of the different observations... other persons, and Kepler himself before his discovery, did not find it by adding together the observations. ...it was the sum of the observations, seen under a new point of view, which point of view Kepler's mind supplied. Kepler found it in the facts, because it was there... but also... because he had in his mind those relations of thought which enabled him to find it. ...We too find the law in Kepler's book; but if we did not understand Latin, we should not find it there. ...In like manner, a discoverer must know the language of science, as well as look at the book of nature, in order to find scientific truth. All the discussions and controversies respecting Ideas and Conceptions of which I have spoken, may be looked upon as discussions and controversies respecting the grammar of the language in which nature speaks to the scientific mind. Man is the Interpreter of Nature; not the Spectator merely, but the Interpreter. The study of the language, as well as the mere sight of the characters, is requisite in order that we may read the inscriptions which are written on the face of the world."

"Upon these methods, the obvious thing to remark is, that they take for granted, the very thing which is most difficult to discover, the reduction of the phenomena to formulae... When we have any set of complex facts offered to us; for instance... the facts of the planetary paths, of falling bodies, of refracted rays, of cosmical motions, of chemical analysis; and when, in any of these cases, we would discover the law of nature which governs them, or, if any one chooses so to term it, the feature in which all the cases agree, where are we to look... ? Nature does not present to us the cases in this form... Who will tell us which of the methods of inquiry those historically real and successful inquiries exemplify? Who will carry these formulae through the history of the sciences, as they have really grown up; and shew us that these... methods have been operative in their formation; or that any light is thrown upon the steps of their progress by reference to these formulae?"

"Lagrange... was the first to draw sharply the line of demarcation between physics and metaphysics. The mechanical ideas of Descartes, Leibnitz, Maupertius, and even of Euler, had proved to be more or less hazy and unfruitful from a failure to separate those two distinct regions of thought. Lagrange put an end to this confusion, for no serious attempt has since been made to derive the laws of mechanics from a metaphysical basis."

"However far the phenomena transcend the scope of classical physical explanation, the account of all evidence must be expressed in classical terms. The argument is that simply by the word "experiment" we refer to a situation where we can tell others what we have done and what we have learned and that, therefore, the account of the experimental arrangement and of the results of the observations must be expressed in unambiguous language with suitable application of the terminology of classical physics."

"It is my task to inquire how it has come about that a generation so amazingly proficient in the practice of science can be so amazingly impotent in the understanding of it... the state of unconscious automatism in which science finds itself today is due to the lack throughout history of a critical school working within the scientific movement itself and performing... at least one of the functions, which criticism has performed for literature from the earliest times."

"The conception... of the purely fictitious character of the basic principles of theory was in the eighteenth and nineteenth centuries still far from being the prevailing one. But it continues to gain more and more ground because of the everwidening logical gap between the basic concepts and laws on the one side and the consequences to be correlated with our experiences on the other—a gap which widens progressively with the developing unification of the logical structure, that is with the reduction in the number of the logically independent conceptual elements required for the basis of the whole system."

"It has often been said... that the man of science is a poor philosopher. Why then should it not be the right thing to let the philosopher do the philosophizing? ...it can not be right at a time when the very foundations of physics itself have become as problematic as they are now. ...the physicist cannot simply surrender to the philosopher the critical contemplation of theoretical foundations; for he... knows best and feels more surely where the shoe pinches. In looking for a new foundation, he must try to make clear in his own mind just how far the concepts which he uses are justified, and are necessities."

"I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science. ...A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is... the mark of distinction between a mere artisan or specialist and a real seeker after truth."

"[I]n textbooks and classrooms... an attempt is made to "purge science of philosophy"... Actually, great advances in sciences have consisted rather in breaking down the dividing walls, and a disregard for meaning and foundation is only prevalent in periods of stagnation. If the scientists, who play an immense social role in our present world, are not to become a class of learned ignoramuses, the education of these men must not restrict itself to the purely technical approach but must give full attention to the philosophical aspect and place of science within the general domain of human thought."

"The interest in science that is not due to its technical application but to its impact upon our common-sense picture of the world we may briefly call the "philosophical" interest. Science teaching in our schools... has for the most part ignored this philosophical interest, and has even proclaimed it a duty of the teacher to present science as completely isolated from its philosophical implications. ...It may seem paradoxical, but the dodging of philosophical issues has very frequently made science graduates captives of obsolete philosophies."

"Very frequently science has served by means of its metaphysical interpretations as a direct guide to human conduct. ...by its metaphysical interpretations it has served what has been called, occasionally, "human engineering." ..."philosophy of science" leads eventually to a research in the "pragmatics of science," which envisages a coherent system containing the physical and biological as well as the sciences of human behavior."

"In actual practice science has always made use of both induction and deduction... The contemporaries of Plato and Aristotle certainly knew from observation that the celestial bodies performed orbits in the heavens that could be identified vaguely as being circular. ...However ...the principle ...was "believed in" much more firmly than this "inductive inference" from observation would warrant. Men believed in it as "intelligible principle"; it seemed very plausible that perfect divine beings like the celestial bodies should also move in "perfect orbits," and the perfect curve is the circle. ...The difference between ancient and modern science was not the use of induction... but the criteria by which a discovered principle was recognized to be valid. The method of "verification" is different now; more weight is given to the agreement... with observed facts than to the agreement... with a world picture that has been accepted for what we called... "philosophical" reasons."

"The Philosopher, in his reflections on spatial and temporal relations, on number and quantity, on matter and motion, is in a region of thought in which the boundary between his own domain and that of the Mathematician is almost non-existent. The Epistemologist has always to take Mathematical knowledge as a kind of touchstone on which to test his theories of the nature of knowledge. The dominant views in various departments of philosophical thinking have been modified in important points by the results of recent Mathematical research, and will, I think, in the future, be further modified from the same quarter."

"In an ideal university the student would not proceed from the most recent observations back to the first principles, but from the first principles to whatever recent observations we claim significant in understanding them. ...The natural sciences derive their principles from the philosophy of nature which, in turn, depends on metaphysics. ...Metaphysics, the study of the first principles, pervades the whole. Dependent on it and subordinate to it are the social and natural sciences."

"Another frame which we impose on the world is space. Whence come the first principles of geometry? Are they imposed on us by logic? Lobachevski has proved not, by creating non-Euclidean geometry. Is space revealed to us by our senses? Still no, for the space our senses could show us differs absolutely from that of the geometer. Is experience the source of geometry? A deeper discussion will show us it is not. We therefore conclude that the first principles of geometry are only conventions; but these conventions are not arbitrary and if transported into another world (that I call the non-Euclidean world and seek to imagine), then we should have been led to adopt others."

"In mechanics we... should see that the principles of this science, though more directly based on experiment, still partake of the conventional character of the geometric postulates. Thus far triumphs; but now we arrive at the physical sciences, properly so called. Here the scene changes; we meet another sort of hypotheses and we see their fertility. Without doubt, at first blush, the theories seem to us fragile, and the history of science proves to us how ephemeral they are; yet they do not entirely perish, and of each of them something remains. It is this something we must seek to disentangle, since there and there alone is the veritable reality."

"The scientist who discovers a theory is usually guided to his discovery by guesses; he cannot name a method by means of which he found the theory and can only say that it appeared plausible to him, that he had the right hunch, or that he saw intuitively which assumptions would fit the facts. Some philosophers have misunderstood this psychological description of discovery as proving that there exists no logical relation leading from the facts to the theory... These philosophers do not see that the same scientist who discovered his theory through guessing presents it to others only after he sees that his guess is justified by the facts. ...The inductive inference is employed not for finding a theory but for justifying it in terms of observational data."

"Rather than treating the content of a natural science as a tight and coherent logical system, we shall... have to consider it as a conceptual aggregate, or 'population', within which there are—at most—localized pockets of logical systematicity. Seen in this light, the problem of scientific rationality can be restated in new terms. ...The extreme 'revolutionary' view of conceptual change remains attractive... only if we make the twin mistakes of equating 'rationality' and 'logicality', and supposing that an entire science has the same logical coherence as (say) Euclid's geometry of Newton's mechanics. ...Those who assume that an entire science necessarily forms a single, coherent intellectual system will correctly infer that 'radical' changes in its intellectual content must also be 'revolutionary'. In this respect, the problems arising over Kuhn's account of scientific change have significant parallels in sociology and elsewhere. The belief that society as a whole forms a single coherent and functional 'social system'... is a direct counterpart to the belief that physics as a whole forms a coherent 'logical system'. An oversytematic analysis of social structure has, in fact, dominated a great part of sociological theory for almost as long as its logical counterpart has dominated the philosophy of science; and, in each case, the revolutionary view is an understandable over-reaction to that domination. ...We can view an entire society as forming a single functional 'system', only if we fail to distinguish the looser social and political relations between the different institutions of a society ...[A]n entire science comprises an 'historical population' of logically independent concepts and theories, each with its own separate history, structure, and implications."

"Nothing... compels us either to treat 'representations' as being inner mental entities, or to regard 'things-in-themselves' as external objects hidden from direct perception, beyond the sensory 'representations' formed within our cerebral mechanisms. Yet this is the sense in which Kant's position was widely understood... by physiologists and psychologists like Müller, Helmholtz and Fechner, and... philosophers like Schopenhuaer. ...The term Vorstellung came to refer simply to the 'ideas' brought into existence as an effect of repeated sensory 'impressions' (Empfindungen); the critical philosophy lost the transcendental character... and... Mach... confuse[d] the theories of Kant's Critiques with those of Berkeley and Hume, which Kant himself had been trying to supercede. ...[W]e can equally well state Kant's epistemic point... using... Darstellung—as used by Hertz, Bühler, and Boltzmann, and Kant himself... a 'representation', in the sense in which a theatrical representation... exhibition or recital provides a public... representation of works of art or music. To darstellen a phenomenon is then to 'demonstrate' or 'display' it... in an entirely public manner what it comprises, or how it operates: as when an hydraulic system... is used to provide a simplified... explanatory model, of a complex electrical circuit. (By contrast... Vorstellung suggests a 'representation' as private or personal... 'in the mind' of an individual. ...[It] carries the same burden as words like 'idea' and 'imagination': it is, in fact, the standard German translation for the Lockean term 'idea'...) ...When Hertz spoke of a dynamical theory as providing a Darstellung of the motions that it explains, and when Wittgenstein declared... propositions of a language darstellen the facts of the world, their assertions had nothing specifically 'mental' or 'inner' about them. ...[C]ollective intellectual functions of concepts and representation techniques in the explanatory activities of science... in terms of Darstellungen can sidetrack... Cartesian and Humean puzzles about the relationship between the 'inner' concepts and 'external' phenomena. At the same time it concedes to Frege all that his anti-psychologism legitimately claimed... that 'explaining' a phenomenon requires us not just to imagine inwardly... but to demonstrate publicly the nature of the relationships..."

"To expect to reorganise our ideas of Time, Space, and Measurement without some discussion which must be ranked as philosophical is to neglect the teaching of history... it is well to understand the limitations to the meaning of philosophy in this connection. It has nothing to do with ethics or theology or the theory of aesthetics. It is solely engaged in determining the most general conceptions which apply to things observed by the senses. Accordingly it is not even metaphysics: it should be called pan-physics. Its task is to formulate those principles of science which are employed equally in every branch of natural science. ...The philosophy of science is the endeavour to formulate the most general characters of things observed. ...in human thought the particular precedes the general. Accordingly the philosophy will not advance until the branches of science have made independent progress. Philosophy then appears as a criticism and a corrective, and what is now to the purpose as an additional source of evidence in times of fundamental reorganisation."

"This assignment of the role of philosophy is borne out by history. It is not true that science has advanced in disregard of any general discussion of the character of the universe. The scientists of the Renaissance and their immediate successors of the seventeenth century, to whom we owe our traditional concepts, inherited from Plato, Aristotle and the medieval scholastics. It is true that the New Learning reacted violently against the schoolmen who were their immediate predecessors; but... they borrowed... certain root-presuppositions respecting space, time, matter, predicate and subject, and logic in general. It is legitimate (as a practical counsel in the management of a short life) to abstain from the criticism of scientific foundations so long as the superstructure works. But to neglect philosophy when engaged in the re-formation of ideas is to assume the absolute correctness of the chance philosophic prejudices imbibed from a nurse or a schoolmaster or current modes of expression. It is to enact the part of those who thank Providence that they have been saved from the perplexities of religious enquiry by the happiness of birth in the true faith. The truth is that your available concepts depend upon your philosophy."

"All the world over and at all times there have been practical men, absorbed in 'irreducible and stubborn facts': all the world over and at all times there have been men of philosophic temperament who have been absorbed in the weaving of general principles. It is the union of passionate interest in the detailed facts with equal devotion to abstract generalisation which forms the novelty in our present society. Previously it had appeared sporadically and as if by chance. This balance of mind has now become part of the tradition which infects cultivated thought. It is the salt which keeps life sweet. The main business of universities is to transmit this tradition as a widespread inheritance from generation to generation."

"Nowadays, explicit engagement with the philosophy of science plays almost no role in the training of physicists or physics research. What little the student learns about philosophical issues is typically learned casually, by a kind of intellectual osmosis. ...Careful reflection on philosophical ideas is rare. Even rarer is systematic instruction. Worse still, publicly indulging an interest in philosophy of science is often treated as a social blunder. ...explicitly philosophical approaches to physics are the exception. Things were not always so."

"[C]hallenges to positivism were born out of the context of , which has historically set the first main point of the opposition to positivism (or rather, to reductionism). The basic epistemological tenet of conventionalism holds that the laws of science (such as Newtonian mechanics) and the axioms of mathematics (like Euclidean geometry) are not experimental generalizations, neither a priori knowledge, but conventions or linguistic definitions. ...Henri Poincaré is considered the main proponent of conventionalism."

"Of course, it is well known from the philosophy of science that any evidence whatsoever can be made consistent with any theory whatsoever by introducing enough auxiliary hypotheses."

"Reason may be employed in two ways to establish a point: firstly, for the purpose of furnishing sufficient proof of some principle, as in natural science, where sufficient proof can be brought to show that the movement of the heavens is always of uniform velocity. Reason is employed in another way, not as furnishing a sufficient proof of a principle, but as confirming an already established principle, by showing the congruity of its results, as in astrology the theory of eccentrics and epicycles is considered as established, because thereby the sensible appearances of the heavenly movements can be explained; not, however, as if this proof were sufficient, forasmuch as some other theory might explain them."

"Five geometers—Clairaut, Euler, D'Alembert, Lagrange and Laplace—shared among them the world of which Newton had revealed the existence. They explored it in all directions, penetrated into regions believed inaccessible, pointed out countless phenomena in those regions which observation had not yet detected, and finally—and herein lies the imperishable glory—they brought within the domain of a single principle, a unique law, all that is most subtle and mysterious in the motions of the celestial bodies. Geometry also had the boldness to dispose of the future; when the centuries unroll themselves they will scrupulously ratify the decisions of science."

"Studies serve for delight, for ornament, and for ability. Their chief use for delight, is in privateness and retiring; for ornament, is in discourse; and for ability, is in the judgment and disposition of business. For expert men can execute, and perhaps judge of particulars, one by one; but the general counsels, and the plots and marshalling of affairs, come best from those that are learned. To spend too much time in studies, is sloth; to use them too much for ornament, is affectation; to make judgment wholly by their rules, is the humour of a scholar scholastic]. They perfect nature, and are perfected by experience. For natural abilities are like natural plants, that need proyning by study; and studies themselves do give forth directions too much at large, except they be bounded in by experience. Crafty men contemn studies; simple men admire them; and wise men use them. For they teach not their own use; but that is a wisdom without [outside of] them, and above them, won by observation. Read not to contradict and confute, nor to believe and take for granted, nor to find talk and discourse, but to weigh and consider. Some books are to be tasted, others to be swallowed, and some few to be chewed digested. That is, some books are to be read only parts; others to be read, but not curiously; and some few to be read wholly, and with diligence and attention. Some books also may be read by deputy, and extracts made of them by others; but that would be only in less important arguments, and the meaner sort of books: else distilled books are, like common distilled waters, flashy things. Reading maketh a full man; conference a ready man; and writing an exact man. And, therefore, if a man write little, he had need have a great memory; if he confer little, he had need have a present wit; and if he read little, he had need have much cunning, to seem to know that he doth not."

"The more man inquires into the laws which regulate the material universe, the more he is convinced that all its varied forms arise from the action of a few simple principles. These principles themselves converge, with accelerating force, towards some still more comprehensive law to which all matter seems to be submitted. Simple as that law may possibly be, it must be remembered that it is only one amongst an infinite number of simple laws: that each of these laws has consequences at least as extensive as the existing one, and therefore that the Creator who selected the present law must have foreseen the consequences of all other laws."

"Let such a history be once provided and well set forth, and let there be added to it such auxiliary and light-giving experiments... and the investigation of nature and of all sciences will be the work of a few years. ...In this way, and in this way only, can the foundations of a true and active philosophy be established; and then will men wake as from deep sleep."

"This history I call Primary History, or the Mother History."

"Atomism began life as a philosophical idea that would fail virtually every contemporary test of what should be regarded as 'scientific'; yet, eventually, it became the cornerstone of physical science."

"Scanning the past millennia of human achievement reveals just how much has been achieved during the last three hundred years since Newton set in motion the effective mathematization of Nature. We found that the world is curiously adapted to a simple mathematical description. It is enigma enough that the world is described by mathematics; but by simple mathematics, of the sort that a few years energetic study now produces familiarity with, this is an enigma within and enigma."

"Maxwell in particular noted that the phenomena of electromagnetism did not fit into the scheme of Newtonian mechanics. Whereas it had been thought that only the distance between two objects determined the force one exerted on the other, electric charges in motion, such as are met with in electric currents, were found to produce effects not encountered when charges are at rest. Celestial bodies will only attract each other; electric charges at rest will either attract or repel... they will exert forces only in the direction of the connecting straight line. Oersted discovered that an electric current (...charges in motion) will exert a force on a magnetic needle at right angles to the connecting straight line. Previous observations in astronomy had tended to show that the force between two bodies depended only on their instantaneous configuration, but Hertz showed by experiment that electromagnetic disturbances propagate as waves, at a finite rate of speed. Hence the force experienced by one body can be understood and explained only in terms of the history of the other."

"Maxwell succeeded in casting all known electromagnetic effects into a mathematical form that has endured to this day... known as Maxwell's field equations. Based on Faraday's earlier work, Maxwell stressed the notion of fields, in contrast to Newton's emphasis on the direct action of bodies on each other across empty space ('). Faraday and Maxwell regarded the effect on an electrically charged body as giving rise to stresses in its immediate surroundings. These in turn produce stresses in ever widening circles, gradually diminishing... These stresses... thought of as capable of existence in otherwise empty space, are called fields... intermediaries between material particles and which assume the burden of Newton's action at a distance."

"The old contrast, often amounting to hostility, between scientific and humane subjects needs to be broken down and replaced by a scientific humanism. At the same time, the teaching of science proper requires to be humanized. The dry and factual presentation requires to be transformed... by emphasizing the living and dramatic character of scientific advance... Here the teaching of the history of science, not isolated as at present, but in close relation to general history teaching, would serve to correct the existing atmosphere of scientific dogmatism. It would show at the same time how secure are the conquests of science in the control they give over natural processes and how insecure and provisional, however necessary, are the rational interpretations, the theories and hypotheses put forward at each stage. Past history by itself is not enough, the latest developments of science should not be excluded because they have not yet passed the test of time. It is absolutely necessary to emphasize the fact that science not only has changed but is continually changing, that it is an activity and not merely a body of facts. Throughout, the social implications of science, the powers that it puts into men’s hands, the uses... should be brought out and made real by a reference to immediate experience of ordinary life. ...[I]t should be possible to introduce the teaching of practical scientific methods by making students find out for themselves new relationships in things that already concern them and not in artificially simplified and unnecessarily abstract experiment."

"In every age there is a turning point, a new way of seeing and asserting the coherence of the world. It is frozen in the statues of Easter Island that put a stop to time—and in the medieval clocks of Europe that once also seemed to say the last word about the heavens for ever. Each culture tries to fix its visionary moment, when it was transformed by a new conception either of nature or of man. But in retrospect, what commands our attention as much are the continuities—the thoughts that run or recur from one civilization to another."

"If I were giving this lecture fifty years from now, the word "gravitation" would be as old-fashioned as the word "phlogiston" is to us. Relativity has certainly demoted gravitation as a real explanation, just as Priestley's and Lavoisier's analyses and decoding of chemical reactions destroyed the word "phlogiston.""

"An invention acts rather like a trigger, because, once it's there, it changes the way things are, and that change stimulates the production of another invention, which in turn, causes change, and so on. Why those inventions happened, between 6,000 years ago and now, where they happened and when they happened, is a fascinating blend of accident, genius, craftsmanship, geography, religion, war, money, ambition... Above all, at some point, everybody is involved in the business of change, not just the so-called "great men." Given what they knew at the time, and a moderate amount of what's up here [pointing to head], I hope to show you that you or I could have done just what they did, or come close to it, because at no time did an invention come out of thin air into somebody's head, [snaps fingers] like that. You just had to put a number of bits and pieces, that were already there, together in the right way."

"How curious, after all, is the way in which we moderns think about our world! And it is all so novel, too. The cosmology underlying our mental processes is but three centuries old—a mere infant in the history of thought—and yet we cling to it with the same embarrassed zeal with which a young father fondles his new-born baby."

"Considering the part played by the sciences in the story of our Western civilization, it is hardly possible to doubt the importance which the history of science will sooner or later acquire both in its own right and as the bridge which has been so long needed in between the Arts and the Sciences."

"In spite of all the allegations of self-love, the facts at first associated with the name of a particular man end by being anonymous, lost forever in the ocean of Universal Science. Thus the monograph imbued with individual human quality becomes incorporated, stripped of sentamentalisms, in the abstract doctrine of the general treatise. To the hot sun of actuality will succeed—if they do succeed—the cold beams of the history of learning."

"A law explains a set of observations; a theory explains a set of laws. The quintessential illustration of this jump in level is the way in which Newton’s theory of mechanics explained Kepler’s law of planetary motion. Basically, a law applies to observed phenomena in one domain (e.g., planetary bodies and their movements), while a theory is intended to unify phenomena in many domains. Thus, Newton’s theory of mechanics explained not only Kepler’s laws, but also Galileo’s findings about the motion of balls rolling down an inclined plane, as well as the pattern of oceanic tides. Unlike laws, theories often postulate unobservable objects as part of their explanatory mechanism. So, for instance, Freud’s theory of mind relies upon the unobservable ego, superego, and id, and in modern physics we have theories of elementary particles that postulate various types of quarks, all of which have yet to be observed."

"This statistical regularity in moral affairs fully establishes their being under the presidency of law. Man is now seen to be an enigma only as an individual; in the mass he is a mathematical problem."

"The book, as far as I am aware, is the first attempt to connect the natural sciences into a history of creation."

"The progress of knowledge is very irregular, somewhat resembling the movements of an army, of which some battalions are in vigorous health, while others are sickly or overburdened with baggage. The experimental marches on at a good pace; the observational proceeds but slowly; the speculative is left far in the rear."

"History of science played a very important role for me. Before I knew well how to do an experiment, I knew why Joliot has missed the neutron, why his wife missed the fission, why they succeeded in having artificial radioactivity, and even why they almost missed the other things, by doing very nice experiments, but didn't come to the conclusion. That is science. Science is doubt, is research. It is not something which is—and that is the danger of teaching—which is too academic and which the people explain [to] you... it is like the logic thing that comes out of the computer, which is not true. You have intuition, you have passion."

"Every science may be exhibited under two methods or procedures, the Historical and the Dogmatic. ...The more discoveries are made, the greater becomes the labour of the historical method of study, and the more effectual the dogmatic, because the new conceptions bring forward the earlier ones in a fresh light. ...By the dogmatic method, therefore, must every advanced science be attained, with so much of the historical combined with it as is rendered necessary ..."

"The most important ploy that nineteenth-century European scholars devised to avoid acknowledging that the roots of civilization are Afroasiatic was to minimize the importance of Egyptian, Sumerian, and Semitic contributions and to focus instead almost entirely on the Greeks. According to this idea, the Egyptians, Sumerians, and Semites established rather static and uninteresting cultures, while the really worthwhile developments in the rise of civilization were the work of the dynamic and sophisticated Greeks, who were considered to be of Aryan stock because their language is part of the Indo-European family. ...It was claimed that the Greeks developed their culture all on their own, with virtually no contribution from the earlier civilizations."

"In the nineteenth century C.E., a small but influential group of German scholars led by Karl Otfried Müller decided that the ancient Greek authors did not know what they were talking about—that their traditions of external influences were simply "myths." …They were convinced that the principle of historical explanation was race, and they believed they had discovered the "scientific laws of race." …only the white race ...had the natural ability to create advanced civilizations. ...This "racial science" …served as a useful ideology to explain the "natural right" of white Europeans to dominate the darker peoples of the world."

"Modern science will continue to be blindly destructive as long as its operations are determined by the anarchism of market economic forces. The problem to be solved is whether science, technology, and industry can be brought under genuinely democratic control in the context of a global planned economy, so that all of us can collectively put our hard-won scientific knowledge to mutually beneficial use. I am confident it can be accomplished, but will it? If so, there is reason for optimism. If not... well, to paraphrase Keynes, "in the not-so-long run we're all dead.""

"The strategic act by which Grosseteste and his thirteenth- and fourteenth-century successors created modern experimental science was to unite the experimental habit of the practical arts with the rationalism of twelfth-century philosophy."

"Before the eighth century [B.C.] no scientific astronomy was possible owing to the absence of one indispensable condition, namely, the possession of an exact system of chronology. The old calendar already in use about the year 2500, and perhaps earlier, was composed of twelve s. But as twelve lunar periods make only 354 days, a thirteenth month was from time to time inserted to bring the date at which the festivals recurred each year, into harmony with the seasons. It was only little by little that greater precision was attained by observing at what date the heliac rising of certain fixed stars took place. ...By degrees, direct observation of celestial phenomena, intended either to enable soothsayers to make predictions or to fix the calendar, led to the establishment of the fact that certain... phenomena recurred at regular intervals, and the attempt was then made to base predictions on the calculation of this recurrence or periodicity. This necessitated a strict chronology, at which the Babylonians did not arrive till the middle of the eighth century B.C.: in 747 they adopted the so-called "era of ." ...the moment when, doubtless owing to the establishment of a lunisolar cycle, they kept properly constructed chronological tables. Farther back there was no certainty in regard to the calculation of time. It is from that moment that the records of eclipses begin which Ptolemy used, and which are still sometimes employed by men of science for the purpose of testing their lunar theories."

"When we realize the important rôle played by space-time in our attempts to avoid a belief in absolute rotation, we can well understand that the doctrine of the relativity of all motion would have been absurd in Newton's day. ...any speaker prior to, say, the year 1900 could never have anticipated the discovery of space-time, for its sole justification arose from the negative experiments in optics and electrodynamics attempted at about that time. As for Newton, not only did he not know nothing of the non-mechanical negative experiments, but in addition, the equations of electrodynamics had not been discovered... even if he had conceived of space-time through some divine inspiration, he could never have utilised it for the purpose of establishing the relativity of all motion. His ignorance of non-Euclidean geometry would have rendered the task impossible. In fact, space-time, in the seventeenth century, would have been a hindrance, and the sole result of its premature introduction into science would have been to muddle everything up and render the discovery of Newton's law of gravitation well-nigh impossible. And this brings us to another point which is often true in physical science. Premature discoveries are apt to do more harm than good. ...had the astronomers of the seventeenth century possessed more perfect telescopes, had they recognized that the planets (Mercury, in particular) did not obey Kepler's laws rigorously, Newton's law might never have been discovered. At all events, its correctness would have been questioned seriously and mathematicians might have lost courage and doubted their ability to discover natural laws. Leverrier, for example, might have lacked the necessary assurance to carry out his lengthy calculations leading to the discovery of Neptune. In short, physical science proceeds by successive approximations, and too rapid jumps in the accretion of knowledge are liable to be disastrous."

"The present century has witnessed the emergence of two grand theories of mathematical physics: the Theory of Relativity and the Quantum Theory. Both theories were conceived for coordinating certain bodies of facts which the classical theories were unable to interpret; and neither theory would have seen the day had it not been for the increased refinement of experimental measurements which rendered the disclosure of these facts possible. But although the two theories were born under similar circumstances, they soon branched in opposite directions. The theory of relativity has developed into a doctrine whose principle field of application is found in the world of large-scale phenomena, whereas the quantum theory has become identified with the atomic and subatomic worlds. To this extent the theories are complimentary."

"Inasmuch as both Rayleigh's and Wien's laws of radiation, though incorrect, appear to express facts correctly at opposite limits of temperature and frequency, we may presume that the correct law must have an intermediary form, passing over into Rayleigh's when [temperature] T is large and [frequency] ν small, and into Wein's when the reverse situation... Planck, guided by these considerations, devised a new theory of radiation which he called the "Quantum Theory." From this theory Planck was able to derive a radiation law which satisfied Wien's relation, ...the displacement law [when the temperature is increased, intensities of all the frequencies increase, while the radiation of maximum intensity is directly proportional to the absolute temperature] and Stefan's law, and which was in excellent agreement with experimental measurements at all temperatures."

"1. Small particles called atoms exist and compose all matter; 2. They are indivisible and indestructible; 3. Atoms of the same chemical element have the same chemical properties and do not transmute or change into different elements."

"The genesis of all science can be traced to the contemplation of... occult influences. Astrology preceded astronomy, chemistry grew out of alchemy, and the theory of numbers had its precursor in a sort of numerology which to this day persists in otherwise unaccountable omens and superstitions."

"While we cannot place Pythagoras among the great or event near-great mathematicians, his position in the history of scientific thought remains unchallenged. ...dictum "Number rules the universe" ...in the broad modern sense ...is there anything in the dictum to which a modern scientist could not or would not subscribe? The theories of relativity and quanta have shaken the physical sciences to the very foundation, forcing the physicist to cast overboard such principles as conservation of energy or economy of action, and to revise the very concepts of space, time, matter, cause and effect. Still, number reigns as firmly in the new physics as it did in the old."

"Great is the power of steady misrepresentation; but the history of science shows that fortunately this power does not long endure."

"The rise of the scientific spirit was a notable feature of the Renaissance: men no longer accepted without question the opinions of the ancients about the universe and the laws governing the natural world; dogma was subjected to experiment, and when it failed to survive the test it was rejected and new theories were formulated. Thus science in the modern sense was born, and rapid progress was made in mathematics, physics, chemistry, and biology. But the immediate consequences for technology were confined to a few specialized fields; in the main, technological progress still depended upon the empirical methods by practical men. On the whole, up to 1750 science probably gained more from technology than vice versa. Among the notable exceptions... were the navigational instruments that played so important a part in the great voyages of exploration and in surveying and cartography; the application of the principle of the pendulum to time-measurement; and, particularly, the growing exploitation of chemistry. However, the new outlook on natural phenomena was only one manifestation of a healthy scepticism: technological processes which often had changed very little for centuries were carefully scrutinized to see what improvements could usefully be made. The Royal Society, founded in 1660 to further the investigation of natural phenomena by observation and experiment, in its early days directed at least as much of its attention to the improvement of existing arts and industries as to the advancement of fundamental scientific knowledge. Among the Society's early activities was the founding of Greenwich Observatory in 1675 for the strictly practical purpose of 'finding out the longitude for perfecting navigation'."

"Growing skill in the working of metals is... exemplified by the development of the instrument-maker's craft. To many... we make reference elsewhere—for example, clocks, navigational instruments and balances. ...Brass, ivory, and closed-grained woods, such as box and pear, were the principal materials of the instrument-makers, with brass becoming increasingly favoured because of its rigidity and permanence. For the shaping of metal the lathe was a valuable tool, and the clock-makers in particular developed it greatly for precision work. The engraving of scales was, of course, a most important part of the work: until the advent of mechanical devices, this was done with simple engraving tools and punches, the design being first set out by geometrical methods. The earliest products of the instrument-makers were made mainly for astronomical purposes or to apply astronomical methods in navigation: they included astrolabes, cross-staffs, quadrants, sundials, and orreries, as well as basic geometrical instruments such as compasses and rules. From the seventeenth century, however, a variety of new instruments, or much improved versions of old ones, began to appear. The needs of surveyors led to the elaboration of the hodometer... enabling distances to be measured... Improvements in artillary called for more accurate sighting of cannon, and by the beginning of the seventeenth century the gunner's level had been highly developed. The invention of the telescope and microscope introduced new problems both in the making of lenses and of the instruments in which they were mounted: the new instruments were a regular part of the instrument-maker's trade from about 1660. From 1700 the revolution in science was making still further demands on the craft, and air-pumps, thermometers, barometers, electrical machines, and other instruments were called for in constantly increasing quantities."

"Greek and medieval knowledge accepted the world in its qualitative variety, and regarded nature's processes as having ends, or in technical phrase as teleological. New science was expounded so as to deny the reality of all qualities in real, or objective, existence. Sounds, colors, ends, as well as goods and bads, were regarded as purely subjective — as mere impressions in the mind. Objective existence was then treated as having only quantitative aspects — as so much mass in motion, its only differences being that at one point in space there was a larger aggregate mass than at another, and that in some spots there were greater rates of motion than at others. Lacking qualitative distinctions, nature lacked significant variety. Uniformities were emphasized, not diversities; the ideal was supposed to be the discovery of a single mathematical formula applying to the whole universe at once from which all the seeming variety of phenomena could be derived. This is what a mechanical philosophy means."

"Les hypothèses ne sont point le produit d'une création soudaine, mais le résultat d'une évolution progressive. [Hypotheses are not the product of sudden creation, but the result of progressive évolution.]"

"Science and religion are two human enterprises sharing many common features. They share these features also with other enterprises such as art, literature and music. The most salient features of all these enterprises are discipline and diversity. Discipline to submerge the individual fantasy in a greater whole. Diversity to give scope to the infinite variety of human souls and temperaments. Without discipline there can be no greatness. Without diversity there can be no freedom. Greatness for the enterprise, freedom for the individual—these are the two themes, contrasting but not incompatible, that make up the history of science and the history of religion."

"Science as subversion has a long history. ...Davis and Sakharov belong to an old tradition in science that goes all the way back to the rebels Benjamin Franklin and Joseph Priestley in the eighteenth century, to Galileo and Giordano Bruno in the seventeenth and sixteenth. If science ceases to be a rebellion against authority, then it does not deserve the talents of our brightest children. ...We should try to introduce our children to science today as a rebellion against poverty and ugliness and militarism and economic injustice."

"The two great conceptual revolutions of twentieth-century science, the overturning of classical physics by Werner Heisenberg and the overturning of the foundations of mathematics by Kurt Gödel, occurred within six years of each other within the narrow boundaries of German-speaking Europe. ...A study of the historical background of German intellectual life in the 1920s reveals strong links between them. Physicists and mathematicians were exposed simultaneously to external influences that pushed them along parallel paths. ...Two people who came early and strongly under the influence of Spengler's philosophy were the mathematician Hermann Weyl and the physicist Erwin Schrödinger. ...Weyl and Schrödinger agreed with Spengler that the coming revolution would sweep away the principle of physical causality. The erstwhile revolutionaries David Hilbert and Albert Einstein found themselves in the unaccustomed role of defenders of the status quo, Hilbert defending the primacy of formal logic in the foundations of mathematics, Einstein defending the primacy of causality in physics. In the short run, Hilbert and Einstein were defeated and the Spenglerian ideology of revolution triumphed, both in physics and in mathematics. Heisenberg discovered the true limits of causality in atomic processes, and Gödel discovered the limits of formal deduction and proof in mathematics. And, as often happens in the history of intellectual revolutions, the achievement of revolutionary goals destroyed the revolutionary ideology that gave them birth. The visions of Spengler, having served their purpose, rapidly became irrelevant."

"Progress in science is often built on wrong theories that are later corrected. It is better to be wrong than to be vague."

"According to Descartes, scientists should stay at home and deduce the laws of Nature by pure thought... scientists will need only the rules of logic and knowledge of the existence of God. For four hundred years since Bacon and Descartes... science has raced ahead by following both paths simultaneously. Neither Baconian empiricism nor Cartesian dogmatism has the power to elucidate Nature's secrets by itself, but both together have been amazingly successful. For four hundred years English scientists have tended to be Baconian and French scientists Cartesian. Faraday and Darwin and Rutherford were Baconians; Pascal and Laplace and Poincaré were Cartesians. Newton was at heart a Cartesian, using pure thought... to demolish the Cartesian dogma of vortices. Marie Curie was at heart a Baconian, boiling tons of crude uranium ore to demolish the dogma of the indestructibility of atoms."

"The present revolution of scientific thought follows in natural sequence on the great revolutions at earlier epochs in the history of science."

"...The present revolution of scientific thought follows in natural sequence on the great revolutions at earlier epochs in the history of science. Einstein's special theory of relativity, which explains the indeterminateness of the frame of space and time, crowns the work of Copernicus who first led us to give up our insistence on a geocentric outlook on nature; Einstein's general theory of relativity, which reveals the curvature or non-Euclidean geometry of space and time, carries forward the rudimentary thought of those earlier astronomers who first contemplated the possibility that their existence lay on something which was not flat. These earlier revolutions are still a source of perplexity in childhood, which we soon outgrow; and a time will come when Einstein's amazing revelations have likewise sunk into the commonplaces of educated thought."

"If the idea of physical reality had ceased to be purely atomic, it still remained for the time being purely mechanistic; people still tried to explain all events as the motion of inert masses; indeed no other way of looking at things seemed conceivable. Then came the great change, which will be associated for all time with the names of Faraday, Clerk Maxwell, and Hertz."

"Scientific thought is a development of pre-scientific thought."

"I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science. So many people today—and even professional scientists—seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is—in my opinion—the mark of distinction between a mere artisan or specialist and a real seeker after truth."

"What Luther's burning of the Papal Bull was in the religious field, in the field of natural science was the great work of Copernicus, in which he, although timidly... threw down a challenge to ecclesiastical superstition. From then on natural science was in essence emancipated from religion, although the complete settlement of accounts in all details has gone on to the present day and in many minds is still far from being complete. But from then on the development of science went forward with giant strides, increasing, so to speak, proportionately to the square of the distance in time from its point of departure, as if it wanted to show the world that for the motion of the highest product of organic matter, the human mind, the law that holds good is the reverse of that for the motion of inorganic matter."

"The impression that science is over has occurred many times in various branches of human knowledge, often because of an explosion of discoveries made by a genius or a small group of men in such a short time that average minds could hardly follow and had the unconscious desire to take breath, to get used to the unexpected things that came to be revealed. Dazzled by these new truths, they could not see beyond. Sometimes an entire century did not suffice to produce this accommodation."

"Christians believed in a teleological cosmos, one created by an omniscient God, a Grand Designer, for a specific purpose. This comforting view was threatened by the new statistical methods in physics, and also by Darwin's theory of evolution, which assumes that chance may intervene between generations to introduce new characteristics."

"The Egyptians were also busy with agriculture, dairying, pottery, glass-making, weaving, ship-building, and carpentry of every sort. This technical activity rested upon a basis of empirical knowledge... To deny it the name of science because it was, perhaps, handed down by tradition to apprentices instead of being written in a book is not wholly just. Technical problems also certainly clamoured for solution in connection with their gold-work, weaving, pottery, hunting, fishing, navigation, basket-work, culture of cereals, culture of flax, baking and brewing, vine-growing and wine-making, stone-cutting and stone-polishing, carpentry, joinery, boat-building, and the many other processes so accurately figured on the walls of the tombs of the nobles at Sakara. In all these techniques lay the germ of science."

"Progress was often achieved by a "criticism from the past"… After Aristotle and Ptolemy, the idea that the earth moves - that strange, ancient, and "entirely ridiculous", Pythagorean view was thrown on the rubbish heap of history, only to be revived by Copernicus and to be forged by him into a weapon for the defeat of its defeaters. The Hermetic writings played an important part in this revival, which is still not sufficiently understood, and they were studied with care by the great Newton himself. Such developments are not surprising. No idea is ever examined in all its ramifications and no view is ever given all the chances it deserves. Theories are abandoned and superseded by more fashionable accounts long before they have had an opportunity to show their virtues. Besides, ancient doctrines and "primitive" myths appear strange and nonsensical only because their scientific content is either not known, or is distorted by philologists or anthropologists unfamiliar with the simplest physical, medical or astronomical knowledge."

"Our freedom to doubt was born out of a struggle against authority in the early days of science. It was a very deep and strong struggle: permit us to question — to doubt — to not be sure. I think that it is important that we do not forget this struggle and thus perhaps lose what we have gained."

"By the way, what I have just outlined is what I call a “physicist’s history of physics,” which is never correct. What I am telling you is a sort of conventionalized myth-story that the physicists tell to their students, and those students tell to their students, and is not necessarily related to the actual historical development, which I do not really know!"

"For indeed it is one of the lessons of the history of science that each age steps on the shoulders of the ages which have gone before. The value of each age is not its own, but is in part, in large part, a debt to its forerunners. And this age of ours if, like its predecessors, it can boast of something of which it is proud, would, could it read the future, doubtless find also much of which it would be ashamed."

"Fundamental changes in science have always been accompanied by deeper digging toward the philosophical foundations. Changes like the transition from the Ptolemaic to the Copernican system, from Euclidean to non-Euclidean geometry, from Newtonian to relativistic mechanics... have brought about a radical change in our common-sense explanation of the world. From all these considerations everyone who is to get a satisfactory understanding of twentieth century science will have to absorb a good deal of philosophical thought. But he will soon feel the same thing holds for a thorough understanding of the science which originated in any period of history."

"Toward the last quarter of the nineteenth century, it was accepted more and more that the phenomena of electromagnetism were not to be reduced to Newtonian mechanics, but were to be reduced from a separate system of principles, of which, in turn, the Newtonian laws were a special case. The "state of a system" is no longer described by the velocity at a certain point x, y, z and at a time t, but by the electric and magnetic field strengths at x, y, z and at a time t. A causal law in the theory of the electromagnetic field is now an equation that allows us to compute from the present distribution of field strengths the future value of field strengths. Mathematically, the causal laws look exactly like those in mechanics except that the velocities u, v, w are replaced by the field strengths. This theory... has been generalized into a "general field theory.""

"[A]mong several theories that are set up to account for a certain domain of observed facts, one will stand out as the best... the theory should be accepted which shows "more" agreement with observed facts... However, this... cannot be the only criterion... If this were so, the best theory would be the mere description of facts; but this would be no theory at all. ...the actual advance of science has always been engineered by a criterion of economy and simplicity. The criteria of Reichenbach and Carnap, which are based, like John Stuart Mill's inductive logic, upon agreement with observations, have to be complemented by the criterion of economy and simplicity which was advanced in the history of science by men like William Ockham, Isaac Newton, and Ernst Mach. In our twentieth century, the importance of crieteria other than mere agreement with observation was stressed by von Mises and Bronowski."

"[F]itness to support desirable conduct on the part of citizens or, briefly, to support moral behavior, has served through the ages as a reason for the acceptance of a theory. In antiquity, the physics of Aristotle and Plato seemed to be fitter, in this respect, than the physics of Epicurus. According to the first, the celestial bodies were made of a nobler material than our earth, while according to the "materialistic" doctrine of Epicurus, all these bodies consisted of the same elements. This latter doctrine, however, made it more difficult to teach the existence of a difference between material and spiritual beings. Since a great many educators and statesmen have been convinced that the belief in this difference is important for the education of good citizens, the Epicurean doctrine was rejected by powerful groups. ...Plato ...in his description of "good government" included the requirement that the followers of Epicurean philosophy should be silenced."

"Included in this “almost nothing,” as a kind of geological afterthought of the last few million years, is the first development of self-conscious intelligence on this planet—an odd and unpredictable invention of a little twig on the mammalian evolutionary bush. Any definition of this uniqueness, embedded as it is in our possession of language, must involve our ability to frame the world as stories and to transmit these tales to others. If our propensity to grasp nature as story has distorted our perceptions, I shall accept this limit of mentality upon knowledge, for we receive in trade both the joys of literature and the core of our being."

"I... praise the newly opened halls of fossil mammals at the . ...teaching us about evolutionary trees by organizing the entire hall as a central trunk and set of branches... placing our brains in our feet and letting us learn by walking. ...the chosen geometry of evolutionary organization... violates the traditional picture of life's history, thus illustrating... an important principle in the history of science: the central role of pictures, graphs, and other forms of visual representation in channeling and constraining our thought. ...Words are an evolutionary afterthought. ...My colleagues have actually done it. ...They have ordered all the fossils into an unconventional iconographic tree that fractures the bias of progress. ...so that we can preambulate along the tree of life and absorb the new scheme viscerally by walking... They have taken Colbert's radical idea and arranged all the fossils by their branching order, not by their later "success" or "advancement." Groups that branch early, appear early in the hall... Sea cows and elephants are at the end of the hall, horses in the middle, and primates near the beginning."

"In this oversimplified view of scientific progress, we advance along a pathway of accumulating knowledge, guided by a timeless method of accurate observation and relentless logic. ... T. H. Huxley's The Crayfish... argues that the study of organisms has progressed through the same three stages followed by all sciences... an initial phase of gathering information without theoretical guidance (Huxley calls this... Natural History... "accurate, but necessarily incomplete and unmethodized knowledge"); a second stage of systemizing and organization... still without guiding theory (called Natural Philosophy); and... the... synthetic climax... Physical Science, "this final stage of knowledge, [where] the phenomena of nature are regarded as one continuous series of causes and effects." ...In this system... Linnaeus occupies the middle rung. ...I would agree with most modern historians of science in branding this... as misleading, and unfair... [T]wo aspects of this older positivist view... lack validity and impede understanding: ...the notion of a timeless based on rigorously objective observation and logic, and ...that earlier systems were either theory-free or theory-poor because explanation can only follow accurate description. Theory-free science makes about as much sense as value-free politics. Both... are oxymoronic. All thinking about the natural world must be informed by theory... The old... theories may have been wrong, but they were as persuasive (and restrictive) in the structuring of knowledge as any more accurate and later system... [W]e cannot collect information without a theory to organize our searches and observations."

"Henry Fairfield Osborn, the dominant paleontologist of his era, and long time director of the American Museum of Natural History, gave the "standard version in his popular book of 1918, The Origin and Evolution of Life... "Lamarck attributed the lengthening of the [giraffe's] neck to the inheritance of bodily modifications caused by the neck-stretching habit. Darwin attributed the lengthening of the neck to the constant selection of individuals and races which were born with the longest necks. Darwin was probably right." …The version has held ever since."

"Progress in science proceeds in fits and starts. Some periods are filled with great breakthroughs; at other times researchers experience dry spells. Scientists put forward results... theoretical and experimental. The results are debated... sometimes... discarded, sometimes... modified, and sometimes they provide inspirational jumping-off points for new and more accurate ways of understanding... a zig zag path toward what we hope will be ultimate truth, a path that began with humanity's earliest attempts to fathom the cosmos and whose end we cannot predict. Whether string theory is an incidental rest stop... a landmark turning point, or... the final destination we do not know. But the last two decades of research by hundreds of... physicists and mathematicians from numerous countries have given us well-founded hope that we are on the right and possibly final track."

"Kuhn... (like Popper and many other predecessors) thought the primary work of science was theoretical. He esteemed theory, and although he had a good sense of experimentation, presented it as of secondary importance. Since the 1980s there has been a substantial shift in emphasis, with historians, sociologists, and philosophers attending seriously to experimental science."

"The whole history of science has been the gradual realization that events do not happen in an arbitrary manner, but that they reflect a certain underlying order, which may or may not be divinely inspired."

"Everything is theoretically impossible, until it is done. One could write a history of science in reverse by assembling the solemn pronouncements of highest authority about what could not be done and could never happen."

"There is an enormous difference between modern science and Greek philosophy, and that is just the empiristic attitude... Since the time of Galileo and Newton, modern science has been based upon a detailed study of nature and upon the postulate that only such statements should be made, as have been verified or at least can be verified by experiment. The idea that one can single out some events from nature by an experiment... to find out what is the constant law in the continuous change, did not occur to the Greek philosophers. Therefore, modern science has from its beginning stood on a much more modest, but at the same time much firmer, basis than ancient philosophy. Therefore, the statements of modern physics are in some way meant much more seriously than the statements of Greek philosophy."

"[E]normous activity, the new spirit... had come... through the Renaissance. ...[A] new authority appeared... independent of Christian religion or philosophy or... the Church, the authority of experience, of the empirical fact. One may trace this... into the philosophy of Occam and Duns Scotus, but it became a vital force... only from the sixteenth century onward. Galileo did not only think about... the pendulum and the falling stone, he tried out by experiments, quantitatively, how these motions took place. ...[E]mphasis on experience was connected with a slow and gradual change in the aspect of reality. While in the Middle Ages... the symbolic meaning of a thing was... its primary reality, the aspect of reality changed... What we can see and touch became primarily real. And this... could be connected with... experiment... [T]his... meant a departure... into an immense new field of... possibilities, and... the Church saw in the new movement the dangers rather than the hopes. ...[R]epresentatives of natural science could argue that experience offers an undisputable truth... made by nature or...in this sense, by God. ...[T]raditional religion ...could argue that... we lose the connection with the essential values... that part of reality beyond the material world. These two arguments do not meet and therefore the problem could not be settled by any... agreement or decision."

"Of the splendid constellation of great names... we admire the living and revere dead far too warmly and too deeply to suffer us sit in judgment on their respective claims to in this or that particular discovery; to balance mathematical skill of one against the experimental dexterity of another, or the philosophical acumen a third. So long as "one star differs from another in glory,"—so long as there shall exist varieties, or even incompatibilities of excellence,—so long will the admiration of mankind be found sufficient for all who merit it."

"In former times the Mathematician and the Physicist were usually one and the same man. Even as late as the eighteenth century this was very generally the case; it was in the nineteenth century that the increasing complexity of both Sciences produced that separation of the two departments which has become continually more marked, and has reached its extreme point in our own time. ...The chief drawback is that each specialist, from lack of interest in, and knowledge of, the progress of the other great department, is apt to miss that large source of inspiration in his own study which is supplied by the other one."

"Mathematical thinking has played a very important part in the formation of the fundamental concepts of the Physicist; very often this part has been a dominant one. Many of these concepts could only have received a precise meaning and... taken definite forms as the result of the work of Mathematicians... For example, the conception of Energy, and the exact meaning of the... law of the Conservation of Energy, emerged as results of the development of the abstract side of molar mechanics, which determined the mode in which the of moving bodies and as work are defined as measurable quantities. Only by the transference and extension of these notions to the molecular domain did the conception involved in the modern doctrine become possible. The doctrine... had been established before Joule and Mayer commenced their work, and was a necessary presupposition of their further development. Joule was able to determine the only owing to the fact that mechanical work was already regarded as a measurable quantity, measured in a manner which had been fixed in the course of the development of the older Mathematical Mechanics. The notion of Potential, fundamental in Electrical Science, and which every Physicist, and every Electrical Engineer, constantly employs, was first developed as a Mathematical conception during the eighteenth century in connection with the theory of the attractions of gravitating bodies. It was transferred to the electrical domain by George Green and others, together with a good deal of detailed mathematics connected with it which had previously been applied to the function."

"Science has only existed for a few hundred years, and its most spectacular achievements have occurred within the last century. Viewed from a historical perspective, the modern era of rapid scientific and technological progress appears to be not a permanent feature of reality, but an abberation, a fluke, a product of a singular convergence of social, intellectual, and political factors."

"The history of civilization details the steps by which men have succeeded in building up an artificial world within the cosmos. Fragile reed as he may be, man, as Pascal says, is a thinking reed: there lies within him a fund of energy, operating intelligently and so far akin to that which pervades the universe, that it is competent to influence and modify the cosmic process. In virtue of his intelligence the dwarf bends the Titan to his will. In every family, in every polity that has been established, the cosmic process in man has been restrained and otherwise modified by law and custom; in surrounding nature, it has been similarly influenced by the art of the shepherd, the agriculturist, the artisan. As civilization has advanced, so has the extent of this interference increased; until the organized and highly developed sciences and arts of the present day have endowed man with a command over the course of non-human nature greater than that once attributed to the magicians. ...a right comprehension of the process of life and of the means of influencing its manifestations is only just dawning upon us. We do not yet see our way beyond generalities; and we are befogged by the obtrusion of false analogies and crude anticipations. But Astronomy, Physics, Chemistry, have all had to pass through similar phases, before they reached the stage at which their influence became an important factor in human affairs. Physiology, Psychology, Ethics, Political Science, must submit to the same ordeal. Yet it seems to me irrational to doubt that, at no distant period, they will work as great a revolution in the sphere of practice."

"In the history of sciences, important advances often come from... the recognition that two hitherto separate observations can be viewed from a new angle and seen to represent nothing but different facets of one phenomenon. Thus, terrestrial and celestial mechanisms became a single science with Newton's laws. Thermodynamics and mechanics were unified through statistical mechanics, as were optics and electromagnetism through Maxwell's theory of magnetic field, or chemistry and through quantum mechanics. Similarly different combinations of the same atoms, obeying the same laws, were shown by biochemists to compose both the inanimate and animate worlds. ... Despite such generalizations, however, large gaps remain... Following the line from physics to sociology, one goes from simpler to the more complex objects... from the poorer to the richer empirical content, as well as from the harder to the softer system of hypotheses and experimentation. ...Because of the hierarchy of objects, the problem is always to explain the more complex in terms and concepts applying to the simpler. This is the old problem of reduction, emergence, whole and parts... an understanding of the simple is necessary to understand the more complex, but whether it is sufficient is questionable. ...the appearance of life and later of thought and language—led to phenomena that previously did not exist... To describe and to interpret these phenomena new concepts, meaningless at the previous level, are required. ...At the limit total reductionism results in absurdity. ...explaining democracy in terms of the structure and properties of elementary particles... is clearly nonsense."

"Great courageous spirits like Abelard and Saint Thomas Aquinas dared to introduce into Catholicism the concepts of Aristotelian logic, and thus founded scholastic philosophy. But when the Church took the sciences under her wing, she demanded that the forms in which they moved be subjected to the same unconditioned faith in authority as were her own laws. And so it happened that scholasticism, far from freeing the human spirit, enchained it for many centuries to come, until the very possibility of free scientific research came to be doubted. At last, however, here too daylight broke, and mankind, reassured, determined to take advantage of its gifts and to create a knowledge of nature based on independent thought. The dawn of the day in history is known as the Renaissance or the Revival of Learning."

"The Copernican revolution... revealed that the earth is not the center of the universe... The second, the Darwinian revolution... revealed that we are not created divinely or uniquely but instead evolved from simpler animals by a process of natural selection. The third great revolution, the Freudian revolution of Vienna 1900, revealed that we do not consciously control our own actions but are instead driven by unconscious motives. This... later led to the idea that human creativity... stems from conscious access to underlying, unconscious forces."

"When Galilei let balls of a particular weight, which he had determined himself, roll down an inclined plain, or Torricelli made the air carry a weight, which he had previously determined to be equal to that of a definite volume of water; or when, in later times, Stahl changed metal into lime, and lime again into metals, by withdrawing and restoring something, a new light flashed on all students of nature. They comprehended that reason has insight into that only, which she herself produces on her own plan, and that she must move forward with the principles of her judgments, according to fixed law, and compel nature to answer her questions, but not let herself be led by nature, as it were in leading strings, because otherwise accidental observations made on no previously fixed plan, will never converge towards a necessary law, which is the only thing that reason seeks and requires. Reason, holding in one hand its principles, according to which concordant phenomena alone can be admitted as laws of nature, and in the other hand the experiment, which it has devised according to those principles, must approach nature, in order to be taught by it: but not in the character of a pupil, who agrees to everything the master likes, but as an appointed judge, who compels the witnesses to answer the questions which he himself proposes. Therefore even the science of physics entirely owes the beneficial revolution in its character to the happy thought, that we ought to seek in nature (and not import into it by means of fiction) whatever reason must learn from nature, and could not know by itself, and that we must do this in accordance with what reason itself has originally placed into nature. Thus only has the study of nature entered on the secure method of a science, after having for many centuries done nothing but grope in the dark."

"It is not an unusual phenomenon in the history of science that views which were once considered antiquated and out of date suddenly come into favor again, though in a more or less modified form. An extremely interesting case of this kind is presented by the revolution in our ideas of electric phenomena which has taken place within the last 10 years... The modern theory of electrical and allied optical phenomena... [i.e.,] the "electron theory," means practically a return to views as laid down in the sixties and seventies by Wilhelm Weber and Zöllner, but modified by the results of Maxwell's and Hertz's researches. W. Weber imagined electric phenomena as the actions of elementary electrical particles—so called "electric atoms"—whose mutual influence depended not only upon their positions but also upon their relative velocities and accelerations. ...most of the laws of electrodynamics when expressed from the standpoint of pure phenomenology in the shape of differential equations, are much more simple and convenient than Weber's formulæ. ...Faraday and Maxwell brought about a general feeling that... a finite rate of propagation would have to take the place of action at a distance. ...Maxwell's formulæ [were] wholly void ...of atomistic conceptions ...According to Maxwell... the vibrations of light were not mechanical, but electrical vibrations of the ether, and the two constants by which Maxwell defined the electric and magnetic behaviour of every body (the dielectric constant and the magnetic permeability) had also to be the determining elements in its refractive power. Although the condition... was well fulfilled in a number of bodies, ...many bodies, notably water...sufficed to prove the inadequacy of the theory... To this was added the dependence of the refractive index upon the colour [frequency], for which the original theory gave no explanation whatever. H. A. Lorentz showed that the foundations of an electromagnetic theory of dispersion could be laid in a manner quite analogous to the mechanical theory, by regarding every molecule as the origin of electric vibrations of a definite period. He says:—"Let there be in every material particle several material points charged with electricity, of which, however, only one be movable, and have the charge e and the mass μ." Lorentz derives the equations of dispersion from this fundamental assumption of vibrating charged particles. ... In his Faraday Memorial Address of 1881 Helmholtz points out that Faraday's law necessarily implies the existence of electric atoms. ...when a neutral molecule—say NaCl—splits up in +Na and -CI when dissolved in water, it is most probable that both the sodium and the chlorine atom had their charges beforehand... equal and opposite. But if we consider a ray of light traversing a crystal of salt, the charges and the atoms they accompany must be thrown into vibrations, and must influence the propagation of the light. ... In the years 1890-93 a number of works appeared by F. Richarz, H. Ebert and G. Johnstone Stoney, mostly dealing with the mechanism of the emission of luminous vapours, and in which attempts are made, on the basis of the kinetic theory of gases, to determine the magnitude of the elementary electrical quantity, called by Stoney... the now universally accepted name of electron. ...that one electron contains about 10-10 electrostatic units. ...a whole series of other methods... tend to very similar values. ... In 1896 a pupil of Lorentz, P. Zeeman, discovered a phenomenon whose existence Faraday had vainly sought for in 1862. If a luminous vapour, say a sodium flame, is brought into a strong magnetic field, the spectrum lines of the vapour show peculiar changes, consisting of a doubling or trebling, according to the line of vision. These changes are predicted by Lorentz's theory. The Zeeman phenomenon further permitted a determination of the inert mass connected with the vibrating charges, and then a striking result was obtained: the vibrating electron is always negatively charged, while the positive charge is stationary. ...The original and almost tacit assumption that the whole ion—i.e., the chemical atom plus its valency charge—was in oscillation must, therefore, be abandoned. We must suppose that the charge, just as is the case in electrolysis, has also an independent mobility in the light-emitting molecule, and that the mass concerned in the Zeeman phenomenon is that of the electron itself. We thus arrive at a view which nearly coincides with the old conception of Weber, but with the important difference that instead of a direct action at a distance we have an action transmitted by the ether, and further, that we have now a perfectly distinct numerical estimate of the magnitude of the electric atoms."

"Historically, the investigations of oscillatory motions was motivated by the desire to improve methods of telling time. ...In the seventeenth century the need to measure small periods of time accurately for the purpose of telling longitude at sea caused scientists to search for increasingly accurate clocks. The search resulted in some major successes that were at least as valuable for the advancement of mathematics and the study of other phenomena of nature, such as light and sound, as they were for the specific problem of measuring time. Scientists naturally concentrated on any physical phenomena that seemed to be periodic or repetitive and might therefore be related to the periodic motion of the planets. Two phenomena recommended themselves for closer investigation, the motion of an object or bob... on a spring, and the motion of a pendulum. The first of those attracted the attention of Robert Hooke... Suppose d is the increase or decrease in the length of the spring resulting from extension or contraction. Hooke found that the restoring force the spring exerts is proportional to d; that is, the force is a constant k, say, times d. This is the meaning of [Ut tensio, sic vis ("as the extension, so the force")]..."

"All "if" statements about the past are as dubious as prophecies of the future are. It seems fairly plausible that if Alexander or Ghengis Khan had never been born, some other individual would have filled his place and executed the design of the Hellenic or Mongolic expansion; but the Alexanders of philosophy and religion, of science and art, seem less expendable; their impact seems less determined by economic challenges and social pressures; and they seem to have a much wider range of possibilities to influence the direction, shape and texture of civilizations."

"If conquerors be regarded as the engine-drivers of History, then the conquerors of thought are perhaps the pointsmen who, less conspicuous to the traveller's eye, determine the direction of the journey."

"We are tempted to... fall into the mistaken belief that the advance of knowledge has always been a continuous, cumulative process along a road which steadily mounts from the beginnings of civilization to our present dizzy height. This, of course, is not the case. In the sixth century B.C., educated men knew that the earth was a sphere; in the sixth century A.D., they again thought it was a disc, or resembling in shape the Holy Tabernacle. In looking back... There are tunnels on the road, whose length is measured in miles, alternating with stretches in full sunlight of no more than a few yards. Up to the sixth century B.C., the tunnel is filled with mythological figures; then for three centuries there is a shrill light; then we plunge into another tunnel, filled with different dreams."

"Rationality is very much connected with the tradition in science for the last 300 years, when you're going to end up with some sort of understandable explanation of something. And I would be disappointed if that were the case."

"Science as we now understand the word is of later birth. If its germinal origin may be traced to the early period when Observation, Induction, and Deduction were first employed, its birth must be referred to that comparatively recent period when the mind,—rejecting the primitive tendency to seek in supernatural agencies for an explanation of all external phenomena,—endeavoured, by a systematic investigation of the phenomena themselves to discover their invariable order and connection."

"The separation of Science from Knowledge was effected step by step as the Subjective Method was replaced by the Objective Method: i.e., when in each inquiry the phenomena of external nature ceased to be interpreted on premisses suggested by the analogies of human nature."

"Although modern Science includes ideas not less transcendental than those included in ancient Science... As abstract expressions of the observed order of nature they are liable at any moment to be displaced in favour of expressions more accurate. They serve as guides and starting-points in research. They are not believed in as absolute existences. In ancient science they were held to be absolute existences, which it was the primary object of research to find, and which, when disclosed to the imagination, required no confrontation with reality."

"He who is ignorant of Motion, says Aristotle, is necessarily ignorant of all natural things. ...Not only was he entirely in the dark respecting the Laws, he was completely wrong in his conception of the nature of Motion. ...He thought that every body in motion naturally tends to rest."

"The gist and kernel of mechanical ideas has in almost every case grown up in the investigation of very simple and special cases of mechanical processes; and the analysis of the history of the discussions concerning these cases must ever remain the method at once the most effective and the most natural for laying this gist and kernel bare. ...[I]t is the only way in which a real comprehension of the general upshot of mechanics is to be attained."

"The history of the development of mechanics, is... indispensable to a full comprehension of the science in its present condition. It also affords a simple and instructive example of the processes by which natural science generally is developed."

"We now propose to enter more minutely into subject of our inquiries, and at the same time, without making the history of mechanics the chief topic discussion, to consider its historical development so far as this is requisite to an understanding of the present state of mechanical science... Apart from the consideration that we cannot afford to neglect the great incentives that it is in our power to derive from the foremost intellects of all epochs, incentives which taken as a whole are more fruitful than the greatest men of the present day are able to offer, there is no grander, no more intellectually elevating spectacle than that of the utterances of the fundamental investigators in their gigantic power. Possessed as yet of no methods, for these were created by their labors, and are only rendered comprehensible to us by their performances, they grapple with and subjugate the object of their inquiry, and imprint upon it the forms of conceptual thought. They that know the entire course of the development of science, will, as a matter of course, judge more freely and more correctly of the significance of any present scientific movement than they, who limited in their views, to the age in which their own lives have been spent, contemplate merely the momentary trend that the course of intellectual events takes at the present moment."

"The acquisition of the most elementary truth does not devolve upon the individual alone: it is pre-effected in the development of the race."

"Know that this Universe, in its entirety, is nothing else but one individual being; that is to say, the outermost heavenly sphere, together with all included therein, is as regards individuality beyond all question a single being like Said and Omar. The variety of its substances—I mean the substances of that sphere and all its component parts—is like the variety of the substances of a human being: just as, e.g., Said is one individual, consisting of various solid substances, such as flesh, bones, sinews of various humours, and of various spiritual elements; in like manner this sphere in its totality is composed of the celestial orbs, the four elements and their combinations; there is no vacuum whatever therein, but the whole space is filled up with matter. Its centre is occupied by the earth, earth is surrounded by water, air encompasses the water, fire envelopes the air, and this again is enveloped by the fifth substance (quintessence). These substances form numerous spheres, one being enclosed within another so that no intermediate empty space, no vacuum, is left. One sphere surrounds and closely joins the other. All the spheres revolve with constant uniformity, without acceleration or retardation; that is to say, each sphere retains its individual nature as regards its velocity and the peculiarity of its motion; it does not move at one time quicker, at another slower. Compared with each other, however, some of the spheres move with less, others with greater velocity. The outermost, all-encompassing sphere, revolves with the greatest speed; it completes its revolution in one day, and causes every thing to participate in its motion, just as every particle of a thing moves when the entire body is in motion; for all existing beings stand in the same relation to that sphere as a part of a thing stands to the whole. These spheres have not a common centre; the centres of some of them are identical with the centre of the Universe, while those of the rest are different from it. Some of the spheres have a motion independent of that of the whole Universe, constantly revolving from East to West, while other spheres move from West to East. The stars contained in those spheres are part of their respective orbits; they are fixed in them, and have no motion of their own, but participating in the motion of the sphere of which they are a part, they themselves appear to move. The entire substance of this revolving fifth element is unlike the substance of those bodies which consist of the other four elements, and are enclosed by the fifth element."

"Through the constant revolution of the fifth element, with all contained therein, the four elements are forced to move and to change their respective positions, so that fire and air are driven into the water, and again these three elements enter the depth of the earth. Thus are the elements mixed together; and when they return to their respective places, parts of the earth, in quitting their places, move together with the water, the air and the fire. In this whole process the elements act and react upon each other. The elements intermixed, are then combined, and form at first various kinds of vapours; afterwards the several kinds of minerals, every species of plants, and many species of living beings, according to the relative proportion of the constituent parts. All transient beings have their origin in the elements, into which again they resolve when their existence comes to an end. The elements themselves are subject to being transformed from one into another; for although one substance is common to all, substance without form is in reality impossible, just as the physical form of these transient beings cannot exist without substance."

"[T]he principal part in the human body, namely, the heart, is in constant motion, and is the source of every motion noticed in the body; it rules over the other members, and communicates to them through its own pulsations the force required for their functions. The outermost sphere by its motion rules in a similar way over all other parts of the universe, and supplies all things with their special properties. Every motion in the universe has thus its origin in the motion of that sphere; and the soul of every animated being derives its origin from the soul of that same sphere."

"The history of science shews that even during the phase of her progress in which she devotes herself to improving the accuracy of the numerical measurement of quantities with which she has long been familiar, she is preparing the materials for the subjugation of the new regions, which would have remained unknown if she had been contented with the rough methods of her early pioneers. I might bring forward instances gathered from every branch of science... But the history of the science of terrestrial magnetism affords us a sufficient example of what may be done by experiments in concert, such as we hope some day to perform in our Laboratory."

"[T]he application of algebra to geometry... far more than any of his metaphysical speculations, has immortalized the name of Descartes, and constitutes the greatest single step ever made in the progress of the exact sciences."

"Do what we will, we always, more or less, construct our own universe. The history of science may be described as the history of the attempts, and the failures, of men " to see things as they are.""

"With the development of the sciences and with the articulation of the machine in practical life, the realm of order was transferred from the absolute rulers, exercising a personal control, to the universe of impersonal nature and to a particular group of artifacts and customs we call the machine. The royal formula of purpose—"I will"—was translated into the causal terms of science—"It must." By partly supplanting the crude desire for personal dominion by an impersonal curiosity and by the desire to understand, science prepared the way for a more effective conquest of the external environment and ultimately for a more effective control of the agent, man, himself."

"These independent objects of Newtonian physics might move, touch each other, collide, or even, by a certain stretch of the imagination, act at a distance: but nothing could penetrate them except in the limited way that light penetrated translucent substances. This world of separate bodies, unaffected by the accidents of history or geographic location, underwent a profound change with the elaboration of the new concepts of matter and energy that went forward from Faraday and von Mayer through Clerk-Maxwell and Willard Gibbs and Ernest Mach to Planck and Einstein. The discovery that solids, liquids, and gases were phases of all forms of matter modified the very conceptions of substance, while the identification of electricity, light, and heat as aspects of a protean energy, and the final break-up of "solid" matter into particles of this same ultimate energy lessened the gap, not merely between various aspects of the physical world, but between the mechanical and the organic. Both matter in the raw and the more organized and internally self-sustaining organisms could be described as systems of energy in more or less stable, more or less complex, states of equilibrium."

"The history of science is rich in the example of the fruitfulness of bringing two sets of techniques, two sets of ideas, developed in separate contexts for the pursuit of new truth, into touch with one another."

"While, by the present methods of teaching, a knowledge of science in its present state of advancement is imparted very successfully, eminent and far-sighted men have repeatedly been obliged to point out a defect which too often attaches to the present scientific education of our youth. It is the absence of the historical sense and the want of knowledge of the great researches upon which the edifice of science rests."

"If we study the history of science we see happen two inverse phenomena, so to speak. Sometimes simplicity hides under complex appearances; sometimes it is the simplicity which is apparent, and which disguises extremely complicated realities. ...What is more complicated than the confused movements of the planets? What simpler than Newton's law? ...In the kinetic theory of gases, one deals with molecules moving with great velocities, whose paths, altered by incessant collisions, have the most capricious forms... The observable result is Mariotte's simple law. ...The law of great numbers has reestablished simplicity in the average. ...No doubt, if our means of investigation should become more and more penetrating, we should discover the simple under the complex, then the complex under the simple, then again the simple under the complex, and so on, without our being able to foresee what will be the last term. We must stop somewhere, and that science may be possible, we must stop when we have found simplicity. This is the only ground on which we can rear the edifice of our generalizations."

"Zoologists maintain that the embryonic development of an animal recapitulates in brief the whole history of its ancestors throughout geologic time. It seems it is the same in the development of minds. The teacher should make the child go over the path his fathers trod; more rapidly, but without skipping stations. For this reason the history of science should be our first guide."

"In my presentation I... follow the genetic method. The essential idea... is that the order in which knowledge has been acquired by the human race will be a good teacher for its acquisition by the individual. The sciences came in a certain order; an order determined by human interest and inherent difficulty. Mathematics and astronomy were the first sciences really worth the name; later came mechanics, optics, and so on. At each stage of its development the human race has had a certain climate of opinion, a way of looking, conceptually, at the world. The next glimmer of fresh understanding had to grow out of what was already understood. The next move forward, halting shuffle, faltering step, or stride with some confidence, was developed upon how well the [human] race could then walk. As for the human race, so for the human child. But this is not to say that to teach science we must repeat the thousand and one errors of the past, each ill-directed shuffle. It is to say that the sequence in which the major strides forward were made is a good sequence in which to teach them. The genetic method is a guide to, not a substitute for, judgement."

"The history of science, like the history of all human ideas, is a history of irresponsible dreams, of obstinacy, and of error. But science is one of the very few human activities — perhaps the only one — in which errors are systematically criticized and fairly often, in time, corrected. This is why we can say that, in science, we often learn from our mistakes, and why we can speak clearly and sensibly about making progress there."

"The History of Electricity is a field full of pleasing objects, according to all the genuine and universal principles of taste, deduced from a knowledge of human nature. Scenes like these, in which we see a gradual rise and progress in things, always exhibit a pleasing spectacle to the human mind. Nature, in all her delightful walks, abounds with such views, and they are in a more especial manner connected with every thing that relates to human life and happiness; things, in their own nature, the most interesting to us. Hence it is, that the power of association has annexed crouds of pleasing sensations to the contemplation of every object, in which this property is apparent. This pleasure, likewise, bears a considerable resemblance to that of the sublime, which is one of the most exquisite of all those that affect the human imagination. For an object in which we see a perpetual progress and improvement is, as it were, continually rising in its magnitude; and moreover, when we see an actual increase, in a long period of time past, we can not help forming an idea of an unlimited increase in futurity; which is a prospect really boundless, and sublime."

"Let us not... contend about merit, but let us all be intent on forwarding the common enterprize, and equally enjoy any progress we may make towards succeeding in it; and above all, let us acknowledge the guidance of that Great Being, who has put a spirit in man, and whose inspiration giveth him understanding."

"It is a remarkable fact in the history of science, that the more extended human knowledge has become, the more limited human power, in that respect, has constantly appeared. This globe, of which man imagines the haughty possessor, becomes, in the eyes of astronomer, merely a grain of dust floating in immensity of space: an earthquake, a tempest, an inundation, may destroy in an instant an entire people, or ruin the labours of twenty ages. ...But if each step in the career of science thus gradually diminishes his importance, his pride has a compensation in the greater idea of his intellectual power, by which he has been enabled to perceive those laws which seem to be, by their nature, placed for ever beyond his grasp."

"The more advanced the sciences have become, the more they have tended to enter the domain of mathematics, which is a sort of center towards which they converge. We can judge of the perfection to which a science has come by the facility, more or less great, with which it may be approached by calculation."

"[S]cientific physics dates its existence from the discovery of the differential calculus. Only when it was learned how to follow continuously the course of natural events, attempts, to construct by means of abstract conceptions the connection between phenomena, met with success. To do this two things are necessary: First, simple fundamental concepts with which to construct; second, some method by which to deduce, from the simple fundamental laws of the construction which relate to instants of time and points in space, laws for finite intervals and distances, which alone are accessible to observation..."

"Up until the publication of Thomas Kuhn's The Structure of Scientific Revolutions in 1962, the history, philosophy, and sociology of science maintained an internalist approach to scientific knowledge claims. Science was seen as somehow above any social, political, or cultural influences, and therefore, the examinations of scientific knowledge focused on areas such as 'discoveries,' 'famous men,' and 'the scientific revolution in the West.' When Kuhn opened the door to the possibility that external factors were involved in the development of scientific paradigms, science studies assumed a more critical tone."

"Histories of scientific thought tend to obscure the revolutionary state of knowledge in the age of Archimedes—the Hellenistic period—toning down the differences between it, the natural philosophy of classical Greece two centuries earlier, and even the prescientific knowledge of ancient Egypt and Mesopotamia."

"Humans may crave absolute certainty; they may aspire to it; they may pretend, as partisans of certain religions do, to have attained it. But the history of science — by far the most successful claim to knowledge accessible to humans — teaches that the most we can hope for is successive improvement in our understanding, learning from our mistakes, an asymptotic approach to the Universe, but with the proviso that absolute certainty will always elude us."

"The history of science—especially physics—has in part been the tension between the natural tendency to project our everyday experience on the universe and the universe's noncompliance..."

"The relativity and quantum theories provide good examples of one of the most characteristic features in the development of scientific ideas—namely the fact that every major advance, resulting in a new representation which post factum can be seen to have reduced the earlier picture to one whose results approximate closely to those of the newer one in special cases, has been connected with a revolutionary change in outlook, and with a radical revision of the epistemological and metaphysical foundations of the earlier picture. It is at such turning-points that scientific thought is most clearly revealed as creative speculation, kept within certain boundaries, and corrected, by facts and experimental evidence... akin to that sphere of inspiration which brings about the great creations of art: both constitute sudden and unpredictable insights into reality which no artificial and mechanical devices, such as computers, could ever achieve. ...science in the making can be seen to be as much an experiment with ideas as a search after significant experimental data."

"The history of science should be the leading thread in the history of civilization."

"The history of science familiarizes us with the ideas of evolution and the continuous transformation of human things... It shows us that if the accomplishments of mankind as a whole are grand, the contributions of each is small."

"It is childish to assume that science began in Greece; the Greek "miracle" was prepared by millenia of work in Egypt, Mesopotamia and possibly in other regions. Greek science was less an invention than a revival."

"Hellenic science is a victory of rationalism, which appears greater, not smaller, when one is made to realize that it had been won in spite of the irrational beliefs of the Greek people; all in all, it was a triumph of reason in the face of unreason. Some knowledge of Greek superstitions is needed not only for a proper appreciation of that triumph but also for the justification of occasional failures, such as the many Platonic aberrations."

"The historical order is very interesting, but accidental and capricious; if we would to understand the growth of knowledge, we cannot be satisfied with accidents, we must explain how knowledge was gradually built up."

"The history of science should not be an instrument to defend any kind of social or philosophic theory; it should be used only for its own purpose, to illustrate impartially the working of reason against unreason, the gradual unfolding of truth, in all its forms, whether pleasant or unpleasant, useful of useless, welcome or unwelcome."

"Men of science have made abundant mistakes of every kind; their knowledge has improved only because of their gradual abandonment of ancient errors, poor approximations, and premature conclusions."

"Science, especially evolutionary sciences, can only proceed from learning about theories of hypotheses that do not stand the test of time."

"That the Babylonians were Syrians, I believe that nobody will deny. Consequently, they are greatly mistaken who say that it is not possible that the Syrians know something of such matters (astronomy), since these Syrians were the inventors and the first Masters in these matters. Ptolemy again renders witness to this in the "Syntax" (Almageste), because when he chooses an origin for the computation of the Sun, the Moon and the five planets, he does not start with the years of Greek kings, but with those of the kings of Babylon, that is, Nebuchadnezzar, king of the Assyrians. I said Nebuchadnezzar, not the one of whom the prophet Daniel was the contemporary, but another more ancient. Ptolemy has thus given in the "Syntax" that the years that have passed since this first Nebuchadnezzar ---- i.e. of the Babylonian and Persian kings ---- until Philip (Arrhidaeus) the Macedonian, the successor of Alexander the founder of Alexandria, (are in the number of) four hundred and twenty-four years. There he rightly shows that he found among the Babylonians, and not among the Greeks, the beginning and foundation of the calculations which he made. It is thus on this foundation that he built and that he piled up the many calculations that he made."

"The history of science on the part of students will give them a better understanding of the broad tendencies which have determined the general course of scientific progress, will enlarge their appreciation of the work of successive generations, and tend to guard them against falling into those ancient pitfalls which have bordered the paths of progress."

"Two points should be specially emphasized in connection with the general theory of relativity. First, it is a purely physical theory, invented to explain empirical physical facts, especially the identity of gravitational and inertial mass, and to coordinate and harmonize different chapters of physical theory, especially mechanics and electromagnetic theory. It has nothing metaphysical about it. Its importance from a metaphysical or philosophical point of view is that it aids us to distinguish in the observed phenomena what is absolute, or due to the reality behind the phenomena, from what is relative, i.e. due to the observer. Second, it is a pure generalization, or abstraction, like Newton's system of mechanics and law of gravitation. It contains no hypothesis, as contrasted with the atomic theory or the theory of quanta, which are based on hypothesis. It may be considered as the logical sequence and completion of Newton's Principia. The science of mechanics was founded by Archimedes, who had a clear conception of the relativity of motion, and may be called the first relativist. Galileo, who was inspired by the reading of the works of Archimedes, took the subject up where his great predecessor had left it. His fundamental discovery is the law of inertia, which is the backbone of Newton's classical system of mechanics, and retains the same central position in Einstein's relativistic system. Thus one continuous line of thought can be traced through the development of our insight into the mechanical processes of nature... characterized by the sequence... Archimedes, Galileo, Newton, Einstein."

"Descartes's so-called dualism is often taken to represent a fundamental revolution in ideas and the starting point of modern philosophy. ...but in substance his work is... better understood as an attempt to conserve the old truths in the face of new threats. His dualism was in essence an armistice... between the established religion and the emerging science of his time. ...isolating the mind from the physical world... ensured that many of the central doctrines of orthodoxy—immortality of the soul, the freedom of will, and, in general, the "special" status of humankind—were rendered immune to any possible contravention by the scientific investigation of the physical world. ... For men such as Descartes, Malebranche, and Leibniz, solving the mind-body problem was vital to preserving the theological and political order inherited from the Middle Ages... For Spinoza, it was a means of destroying that same order and discovering a new foundation for human worth."

"No scientific discovery is named after its original inventor."

"Lagrange's "" is perhaps his most valuable work and still amply repays careful study. ...the full power of the newly developed analysis was applied to the mechanics of points and rigid bodies. The results of Euler, of D'Alembert, and of the other mathematicians of the Eighteenth Century were assimilated and further developed from a consistent point of view. Full use of Lagrange's own made the unification of the varied principles of statistics and dynamics possible... Newton's geometrical approach was now fully discarded; Lagrange's book was a triumph of pure analysis."

"The development of human thought and achievement, as a whole, has not been, as commonly supposed, a continual upward progression, nor even the equivalent of a continuous series of ascertained results. Thoughts and inventions, which seemed on the verge of practical fruition, have often been reduced to nothingness, even at the most decisive moment, through some combination of untoward circumstances; yes, even the very memory of a pathway broken into the Land of Promise is often obliterated and what seemed accomplished fact has had to be recreated by laborious work covering years, decades and even centuries. Just the simplest, most natural and, in the end, almost self-evident facts are the hardest to evolve and elucidate, just what was most decisive and potent of result has been time and again overlooked by the seeker after truth. ...The gold of historic thought, indeed, is as little to be found in the street as the gold of actual daily strife, and it is by no means the task of the historian of broad general scope to give the initial clew to its discovery. He, indeed, can only reproduce the past with fidelity and exactitude. The intuition of the true investigator and pathfinder of today and tomorrow must find its own way to new guiding principles from the work of yesterday, before yesterday, and the distant past."

"David Hume posed the issue in the following way (as rephrased in the black swan problem by... John Stuart Mill) No amount of observations of white swans can allow the inference that all swans are white, but the observation of a single black swan is sufficient to refute that conclusion."

"Science had shifted, thanks to Bacon, into an emphasis on empirical observation. The problem is that, without a proper method, empirical observations can lead you astray. Hume came to... stress the need for some rigor in the gathering and interpretation of knowledge... epistemology... Hume is the first modern epistemologist... he was an obsessive skeptic and never believed... that a link between two items could be established as being causal."

"[T]he ancients possessed a considerable acquaintance with many operations of technical chemistry... Their methods were probably jealously guarded and handed down by successive members of the crafts as precious secrets. ...But, under the conditions in which their industries were prosecuted, the scientific spirit was not free to develop, for science depends essentially upon free inter-communication of facts ...Moreover, the great intellects of antiquity, for the most part, had little sympathy with the operations of artisans, who, at least among the Greeks and Romans, were, for the most part, slaves. Philosophers taught that industrial work tended to lower the standard of thought. The priests, in most ages, have looked more or less askance at attempts, on the part of the laity, to inquire too closely into the causes of natural phenomena. The investigation of nature in early times was impossible for religious reasons. There was an outcry in Athens when the thunderbolts of Zeus were ascribed to the collision of clouds. Anaxagoras, , Plato, Aristotle, Diagoras, and Protagoras were charged by the priests with blasphemy and driven into exile. Prodikos, who deified the natural forces, as did Empedokles the primal elements, was executed for impiety. Sacerdotalism in Athens had no more sympathy with science than had the Holy Congregation in Italy when it banned the writings of Copernicus, Kepler, and Galileo, and sent Giordano Bruno to the stake. The educated Greeks had no interest in observing or in explaining the phenomena of technical processes. However prone they might be to speculation, they had no inclination to experiment or to engage in the patient accumulation of the knowledge of physical facts. ...The influence of a spurious , which lasted through many centuries and even beyond the time of Boyle, was wholly opposed to the true methods of science, and it was only when philosophy had shaken itself free from that chemistry, as a science, was able to develop."

"Where Francis Bacon had provided the manifesto for experimental science, René Descartes... did the same for scientific theory. And though in the three hundred years since 1650, there have been occasional conflicts between the Baconian and Cartesian tendencies in modern science, their opposition has been creative, and out of it have come many of our most profound insights."

"This subject crosses most cultures and places... It might even be argued that this discipline was the link that brought geometric models of the cosmos together with numerical computation in a synthesis that allowed theory to be converted into prediction: the birth of the exact sciences. All this makes it hard to believe that trigonometry has never been given a proper book-length historical treatment in English."

"One cannot genuinely practice the history of a scientific subject without also living and breathing the science itself."

"Our technology is based entirely on mathematics and physics. ...The unprecedented growth of natural science in the 17th century was followed ineluctably by the rationalism of the 18th, by the deification of reason... Science is the most significant phenomenon of modern times, the principal ingredient of our civilization — alas! ...the most important question for the history of culture is: How did our modern natural science come about? It will be conceded that most historical writings either do not consider this question at all, or else deal with it in a very unsatisfactory manner. For example, which are the histories of Greek culture that mention the names of Theaetetus and of Eudoxus, two of the greatest mathematicians of all times? Who realizes that, from the historical point of view, Newton was the most important figure of the 17th century?"

"Without the stupendous work of Ptolemy, which completed and closed antique astronomy, Kepler's , and hence the mechanics of Newton, would have been impossible. Without the conic sections of Apollonius, which Newton knew thoroughly, his development of the law of gravitation is equally unthinkable. And Newton's integral calculus can be understood only as a continuation of Archimedes' determination of areas and volumes. The history of mechanics as an exact science begins with the law of the lever, the laws of hydrostatics and the determination of mass centers by Archimedes. ...all the developments which converge in the work of Newton, those of mathematics, of mechanics and of astronomy, begin in Greece."

"The treatment of the kinetics of a material system by the method of generalised coordinates was first introduced by Lagrange, and has since his time been greatly developed by the investigations of different mathematicians. Independently of the highly interesting, although purely abstract science of theoretical dynamics which has resulted from these investigations, they have proved of great and continually increasing value in the application of mechanics to thermal, electrical and chemical theories, and the whole range of ."

"The important thing for the progress of physics is not the decision that a theory is true, but the decision that it is worth taking seriously—worth teaching to graduate students, worth writing textbooks about, above all, worth incorporating into one’s own research."

"The effect of these researches has been, a persuasion, that we need not despair of seeing, even in our own time, a renovation of sound philosophy, directed by the light which the History of Science sheds. Such a reform, when its Epoch shall arrive, will not be the work of any single writer, but the result of the intellectual tendencies of the age."

"Our species, from the time of its creation, has been travelling onwards in pursuit of truth; and now that we have reached a lofty and commanding position, with the broad light of day around us, it must be grateful to look back on the line of our past progress;—to review the journey."

"The main object of the work was to present such a survey of the advances already made in physical knowledge, and of the mode in which they have been made, as might serve as a real and firm basis for our speculations concerning the progress of human knowledge, and the processes by which sciences are formed."

"The present generation finds itself the heir of a vast patrimony of science; and it must needs concern us to know the steps by which these possessions were acquired, and the documents by which they are secured to us and our heirs for ever."

"The earlier truths are not expelled but absorbed, not contradicted but extended; and the history of each science, which may thus appear like a succession of revolutions, is, in reality, a series of developements."

"In all modern history, interference with science in the supposed interest of religion, no matter how conscientious such interference may have been, has resulted in the direst evils both to religion and to science, and invariably; and, on the other hand, all untrammelled scientific investigation, no matter how dangerous to religion some of its stages may have seemed for the time to be, has invariably resulted in the highest good both of religion and of science."

"Herein lies the truth of all bibles, and especially of our own. ...they are eminently precious, not as a record of outward fact, but as a mirror of the evolving heart, mind, and soul of man. They are true because they have been developed in accordance with the laws governing the evolution of truth in human history, and because in poem, chronicle, code, legend, myth, apologue, or parable they reflect this development of what is best in the onward march of humanity. To say that they are not true is as if one should say that a flower or a tree or a planet is not true; to scoff at them is to scoff at the law of the universe. In welding together into noble form, whether in the book of Genesis, or in the Psalms, or in the book of Job, or elsewhere, the great conceptions of men acting under earlier inspiration, whether in Egypt, or Chaldea, or India, or Persia, the compilers of our sacred books have given to humanity a possession ever becoming more and more precious; and modern science, in substituting a new heaven and a new earth for the old—the reign of law for the reign of caprice, and the idea of evolution for that of creation..."

"The physical doctrine of the atom has got into a state which is strongly suggestive of the epicycles of astronomy before Copernicus."

"We are indeed a blind race, and the next generation, blind to its own blindness, will be amazed at ours."

"Understanding what M-theory really is—the physics it embodies—would transform our understanding of nature at least as radically as occurred in any of the major scientific upheavals of the past."

"This statement appears to us to be conclusive with respect to the insufficiency of the undulatory theory, in its present state, for explaining all the phenomena of light. But we are not therefore by any means persuaded of the perfect sufficiency of the projectile system: and all the satisfaction that we have derived from an attentive consideration of the accumulated evidence, which has been brought forward, within the last ten years, on both sides of the question, is that of being convinced that much more evidence is still wanting before it can be positively decided. In the progress of scientific investigation, we must frequently travel by rugged paths, and through valleys as well as over mountains. Doubt must necessarily succeed often to apparent certainty, and must again give place to a certainty of a higher order; such is the imperfection of our faculties, that the descent from conviction to hesitation is not uncommonly as salutary, as the more agreeable elevation from uncertainty to demonstration. An example of such alternations may easily be adduced from the history of chemistry. How universally had phlogiston once expelled the aërial acid of Hooke and Mayow. How much more completely had phlogiston given way to oxygen! And how much have some of our best chemists been lately inclined to restore the same phlogiston to its lost honours! although now again they are beginning to apprehend that they have already done too much in its favour. In the mean time, the true science of chemistry, as the most positive dogmatist will not hesitate to allow, has been very rapidly advancing towards ultimate perfection."

"Notwithstanding the broad foundation for mechanics laid by Newton in his Principia, and notwithstanding the indefatigable labors of Clairaut, d'Alembert, the Bernoullis, and Euler, there was near the end of the eighteenth century no comprehensive treatise on the science. Its leading principles and methods were fairly well known, but scattered through many works, and presented from divers points of view. It remained for Lagrange to unite them into one harmonious system. Mechanics had not yet freed itself from the restrictions of geometry, though progress since Newton's time had been constantly toward analytical... methods. The emancipation came with Lagrange's Mécanique Analytique published one hundred and one years after the Principia."

"The history of the rainbow from the age of myth to contemporary optics is an example wrought in miniature of our unfolding penetration of and relation to natural phenomena. ...Yet while engaging in itself, the history of the rainbow hides within it another story far more significant than an external history of science. For the changing images of the rainbow reflect to us momentous changes in the fabric of consciousness itself. The history of light, the rainbow, and more generally the history of science continue to act as a text in which we read the psychogenesis of the mind."

"To conclude, logical positivism was progressive compared with the classical positivism of Ptolemy, Hume, d'Alembert, Compte, John Stuart Mill, and Ernst Mach. It was even more so by comparison with its contemporary rivals—neo-Thomisism, neo-Kantianism, intuitionism, dialectical materialism, phenomenology, and existentialism. However, neo-positivism failed dismally to give a faithful account of science, whether natural or social. It failed because it remained anchored to sense-data and to a phenomenalist metaphysics, overrated the power of induction and underrated that of hypothesis, and denounced realism and materialism as metaphysical nonsense. Although it has never been practiced consistently in the advanced natural sciences and has been criticized by many philosophers, notably Popper (1959 [1935], 1963), logical positivism remains the tacit philosophy of many scientists. Regrettably, the anti-positivism fashionable in the metatheory of social science is often nothing but an excuse for sloppiness and wild speculation."

"Unlike the physicist, the psychologist ... investigates processes that belong to the same order—perception, learning, thinking—as those by which he conducts his investigation."

"The difference between Hayek’s view and that of the logical positivists was that he moved in an idealist direction and they emphasized verification."

"Hayek thought there are two orders through which individuals consider the world: the sensory order and the physical order. The sensory order is what we sense. The physical world is the real world of existence beyond our senses that every sane person who is not a solipsist accepts on faith. According to Hayek, advances in science have rendered any correspondence between the real, physical world and the sensory world almost nonexistent. Instead, the natural, real world expresses itself in mathematical relationships. Hayek’s views tended philosophically to solipsism. While he believed in the existence of a physical world external to mind, he ascribed almost no (if any) properties to it. He was not as opposed to positivism as to logical positivism, and it is important to be clear about these terms. Positivism is simply the idea that there should be some correspondence with the material world extrinsic to one’s physical self that one perceives in order for statements about nature to be valid, to be true. Using this broad definition of positivism, Hayek was a positivist. Logical positivism tries to go a step beyond this position. The logical positivists sought to reduce all experience to sensory experience and to reduce every sensory experience to a conclusive or exact statement. This has proven an unattainable goal."

":...Vienna is the origin of so many schools of its own which were dominant in the 1920s. And one of the most fundamental and influential, in which we all were partially caught, was logical positivism. In fact, Mises’ brother, Richard von Mises, became one of the leading figures. Now he and I all grew up in this Ernst Mach philosophy that ultimately everything must be rationally justified…"

"Logical positivism is a very attractive view for people who do not want to worry about what they cannot observe. It is ultimately a theory about meaning, about the content of a theory. According to the positivists, a theory says no more than its observable consequences. Logical positivism has been killed many times over by philosophers. But no matter how many stakes are driven through its heart, it arises unbidden in the minds of scientists. For if the content of a theory goes beyond what you can observe, then you can never, in principle, be sure that any theory is right. And that means there can be interminable arguments about which theory is right that cannot be settled by observation."

"To recap, I had four numbers to add together. If the total came to under 2, then Einstein’s version of quantum reality was correct and the world is deterministic, rather than probabilistic, with quantum entities existing prior to being observed. But if the total came to over 2, then Niels Bohr was right and there is no objective reality out there in the absence of measurement and the subatomic world is ruled by chance and probability. [...] So, sorry Einstein, victory goes to Bohr instead."

"The discomfort that I feel is associated with the fact that the observed perfect quantum correlations seem to demand something like the ‘genetic’ hypothesis [identical twins, carrying with them identical genes]. For me, it is so reasonable to assume that the photons in those experiments carry with them programs, which have been correlated in advance, telling them how to behave. This is so rational that I think that when Einstein saw that, and the others refused to see it, he was the rational man. The other people, although history has justified them, were burying their heads in the sand. I feel that Einstein’s intellectual superiority over Bohr, in this instance, was enormous; a vast gulf between the man who saw clearly what was needed, and the obscurantist. So for me, it is a pity that Einstein’s idea doesn’t work. The reasonable thing just doesn’t work."

"Bohr was inconsistent, unclear, willfully obscure and right. Einstein was consistent, clear, down-to-earth and wrong."

"The EPR paper came out in 1935 and for at least two decades no one paid much attention to it. However, in 1964, the late John Bell published a paper that changed everything. He showed that Einstein’s idea that the results of quantum mechanics could be reproduced by a theory in which Einstein’s notions of realism were included could be tested in the laboratory. Having spent a good deal of time talking to Bell I can tell you that his heart was with Einstein. He often referred to Bohr as an “obscurantist.” But the experiments were carried out by Alain Aspect and others and showed that Einstein was wrong and Bohr was right. I cannot believe that anyone familiar with this would still agree with Einstein."

"His thought experiment with photon and film had not challenged Heisenberg's principle, but now Einstein did turn his attention there. He began looking for an experiment that would allow a more complete collection of data than the Heisenberg team thought possible. If he could find a technique that allowed the simultaneous discovery of position and momentum or time and energy, he would prove the quantum mechanics had indeed not yet brought us to the the secret of the Old One. This effort led the most famous set-pieces of the Einstein "debate" with Bohr over quantum mechanics. Einstein, Bohr, and Ehrenfest would meet in the hotel dining room for breakfast. Einstein would propose a thought experiment. Bohr would think about it. ... During the day's program at Solvay, Heisenberg and Pauli would analyze the experiment that Einstein had proposed. They would find some point where the uncertainty principle fought back, and over dinner, Bohr wold refute the experimental effort while Ehrenfest looked on."

"The mid-twentieth century “Bohr-Einstein debate” about quantum theory is often misinterpreted as a personal clash between wizards. So counter-intuitive are quantum theory’s predictions that, under the leadership of one of its pioneers, Neils Bohr, a myth grew that there is no underlying reality that explains them. Particles get from A to B without passing through the intervening space, where they have insufficient energy to exist; they briefly “borrow” the energy, because we are “uncertain” about what their energy is. Information gets from A to B without anything passing in between – what Einstein called “spooky action at a distance.” And so on....So, while most accounts say that Bohr won the debate, my view is that Einstein, as usual, was seeking an explanation of reality, while his rivals were advocating nonsense. Everett’s interpretation doesn’t make Einstein a demigod. But it does make him right."

"Einstein was not prepared to let us do what, to him, amounted to pulling the ground from under his feet. Later in life, also, when quantum theory had long since become an integral part of modern physics, Einstein was unable to change his attitude—at best, he was prepared to accept the existence of quantum theory as a temporary expedient. "God does not throw dice" was his unshakable principle, one that he would not allow anybody to challenge. To which Bohr could only counter with: "Nor is it our business to prescribe to God how He should run the world.""

"Their dispute went to the fundamental heart of the design of the cosmos. Was there an objective reality that existed whether or not we could ever observe it? Were there laws that restored strict causality to phenomena that seemed inherently random? Was everything in the universe predetermined?"

"Einstein's thinking is always on the ontological level traditional in physics; trying to describe the realities of Nature. Bohr's thinking is always on the epistemological level, describing not reality but only our information about reality."

"The famous debate between Einstein and Bohr began at the Solvay Council in 1927. The debate was about the interpretation of quantum mechanics, but also addressed the fundamental question of what the purpose and aim of a physical theory should be. Their conflicting positions were based on two diametrically opposed philosophical approaches to the fundamental problems of physics. The many books popularising quantum mechanics quite rightly place the emphasis on the problem of interpretation: they discuss the opposing positions of Einstein’s “realism” and the “Copenhagen interpretation” of which Bohr is seen as the leading protagonist."

"We, of course, were sure that on that particular debate Bohr was right and Einstein was wrong."

"The refutation of Einstein’s criticism does not add any new element to the conception of complementarity, but it is of great importance in laying bare a very deep-lying opposition between Bohr’s general philosophical attitude and the still widespread habits of thought belonging to a glorious but irrevocably bygone age in the evolution of science."

"Albert Einstein, who was in many ways the father of quantum mechanics, had a notorious love-hate relation with the subject. His debates with Niels Bohr—Bohr completely accepting of quantum mechanics and Einstein deeply skeptical— are famous in the history of science. It was generally accepted by most physicists that Bohr won and Einstein lost. My own feeling, I think shared by a growing number of physicists, is that this attitude does not do justice to Einstein’s views. Both Bohr and Einstein were subtle men. Einstein tried very hard to show that quantum mechanics was inconsistent; Bohr, however, was always able to counter his arguments. But in his final attack Einstein pointed to something so deep, so counterintuitive, so troubling, and yet so exciting, that at the beginning of the twenty-first century it has returned to fascinate theoretical physicists. Bohr’s only answer to Einstein’s last great discovery—the discovery of entanglement—was to ignore it."

"To this day, many researchers agree with Bohr's pragmatic attitude. The history books say that Bohr has proved Einstein wrong. But others, including myself, suspect that, in the long run, the Einsteinian view might return: that there is something missing in the Copenhagen interpretation. Einstein's original objections could be overturned, but problems still arise if one tries to formulate the quantum mechanics of the entire universe (where measurements can never be repeated), and if one tries to reconcile the laws of quantum mechanics with those of gravitation. But I am running far ahead in my story (I will return to this point in chapter 28). For a correct description of atoms and molecules, quantum mechanics is a perfect theory."

"The other mistake that is widely attributed to Einstein is that he was on the wrong side in his famous debate with Niels Bohr over quantum mechanics, starting at the Solvay Congress of 1927 and continuing into the 1930s. In brief, Bohr had presided over the formulation of a “Copenhagen interpretation” of quantum mechanics, in which it is only possible to calculate the probabilities of the various possible outcomes of experiments. Einstein rejected the notion that the laws of physics could deal with probabilities, famously decreeing that God does not play dice with the cosmos. But history gave its verdict against Einstein—quantum mechanics went on from success to success, leaving Einstein on the sidelines. All this familiar story is true, but it leaves out an irony. Bohr’s version of quantum mechanics was deeply flawed, but not for the reason Einstein thought. The Copenhagen interpretation describes what happens when an observer makes a measurement, but the observer and the act of measurement are themselves treated classically. This is surely wrong: Physicists and their apparatus must be governed by the same quantum mechanical rules that govern everything else in the universe."

"In the famous Einstein–Bohr debates, Bohr defended quantum mechanics against Einstein's yearning for a more classical theory; but some of us are coming to feel in defending his hard-won ground he compromised too much. Quantum mechanics should be pushed as hard as possible, to the point where it can describe within itself a recognizable caricature of the world as it is experienced, and thus begin to provide its own self-consisted interpretation — or else there should be some definite change in its equations. As yet this task has not been accomplished."

"Einstein’s great friend and intellectual sparring partner Niels Bohr had a nuanced view of truth. Whereas according to Bohr, the opposite of a simple truth is a falsehood, the opposite of a deep truth is another deep truth. In that spirit, let us introduce the concept of a deep falsehood, whose opposite is likewise a deep falsehood. It seems fitting to conclude this essay with an epigram that, paired with the one we started with, gives a nice example:“Naïveté is doing the same thing over and over, and always expecting the same result.”"

"There is something there. But just because your theory is good does not mean that the entities in your theory are "really there", whatever that might mean..."

""The physical world is real." That is supposed to be the fundamental hypothesis. What does "hypothesis" mean here? For me, a hypothesis is a statement, whose truth must be assumed for the moment, but whose meaning must be raised above all ambiguity. The above statement appears to me, however, to be, in itself, meaningless, as if one said: "The physical world is cock-a-doodle-do." It appears to me that the "real" is an intrinsically empty, meaningless category (pigeon hole), whose monstrous importance lies only in the fact that I can do certain things in it and not certain others."

"I believe that the first step in the setting of a “real external world” is the formation of the concept of bodily objects and of bodily objects of various kinds. Out of the multitude of our sense experiences we take, mentally and arbitrarily, certain repeatedly occurring complexes of sense impression (partly in conjunction with sense impressions which are interpreted as signs for sense experiences of others), and we attribute to them a meaning—the meaning of the bodily object. Considered logically this concept is not identical with the totality of sense impressions referred to; but it is an arbitrary creation of the human (or animal) mind. On the other hand, the concept owes its meaning and its justification exclusively to the totality of the sense impressions which we associate with it."

"Physical concepts are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world. In our endeavor to understand reality we are somewhat like a man trying to understand the mechanism of a closed watch. He sees the face and the moving hands, even hears its ticking, but he has no way of opening the case. If he is ingenious he may form some picture of a mechanism which could be responsible for all the things he observes, but he may never be quite sure his picture is the only one which could explain his observations. He will never be able to compare his picture with the real mechanism and he cannot even imagine the possibility or the meaning of such a comparison. But he certainly believes that, as his knowledge increases, his picture of reality will become simpler and simpler and will explain a wider and wider range of his sensuous impressions. He may also believe in the existence of the ideal limit of knowledge and that it is approached by the human mind. He may call this ideal limit the objective truth."

"It will be difficult. But the difficulty really is psychological and exists in the perpetual torment that results from your saying to yourself, 'But how can it be like that?' which is a reflection of uncontrolled but utterly vain desire to see it in terms of something familiar. I will not describe it in terms of an analogy with something familiar; I will simply describe it. There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics. So do not take the lecture too seriously, feeling that you really have to understand in terms of some model what I am going to describe, but just relax and enjoy it. I am going to tell you what nature behaves like. If you will simply admit that maybe she does behave like this, you will find her a delightful, entrancing thing. Do not keep saying to yourself, if you can possibly avoid it, 'But how can it be like that?' because you will get 'down the drain', into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that."

"I claim that the success of current scientific theories is no miracle. It is not even surprising to the scientific (Darwinist) mind. For any scientific theory is born into a life of fierce competition, a jungle red in tooth and claw. Only the successful theories survive—the ones which in fact latched onto the actual regularities in nature."

"The most common misunderstanding about science is that scientists seek and find truth. They don't — they make and test models."

"These lectures have shown very clearly the difference between Roger and me. He's a Platonist and I'm a positivist. He's worried that Schrödinger's cat is in a quantum state, where it is half alive and half dead. He feels that can't correspond to reality. But that doesn't bother me. I don't demand that a theory correspond to reality because I don't know what it is. Reality is not a quality you can test with litmus paper. All I'm concerned with is that the theory should predict the results of measurements. Quantum theory does this very successfully. It predicts that the result of an observation is either that the cat is alive or that it is dead. It is like you can't be slightly pregnant: you either are or you aren't."

"A scientific theory is usually felt to be better than its predecessors not only in the sense that it is a better instrument for discovering and solving puzzles but also because it is somehow a better representation of what nature is really like. One often hears that successive theories grow ever closer to, or approximate more and more closely to, the truth. Apparently generalizations like that refer not to the puzzle-solutions and the concrete predictions derived from a theory but rather to its ontology, to the match, that is, between the entities with which the theory populates nature and what is “really there.” Perhaps there is some other way of salvaging the notion of ‘truth’ for application to whole theories, but this one will not do. There is, I think, no theory-independent way to reconstruct phrases like ‘really there’; the notion of a match between the ontology of a theory and its “real” counterpart in nature now seems to me illusive in principle. Besides, as a historian, I am impressed with the implausability of the view. I do not doubt, for example, that Newton’s mechanics improves on Aristotle’s and that Einstein’s improves on Newton’s as instruments for puzzle-solving. But I can see in their succession no coherent direction of ontological development. On the contrary, in some important respects, though by no means in all, Einstein’s general theory of relativity is closer to Aristotle’s than either of them is to Newton’s."

"Origin of knowledge. - Through immense periods of time, the intellect produced nothing but errors; some of them turned out to be useful and species-preserving; those who hit upon or inherited them fought their fight for themselves and their progeny with greater luck. Such erroneous articles of faith, which were passed on by inheritance further and further, and finally almost became part of the basic endowment of the species, are for example: that there are enduring things; that there are identical things; that there are things, kinds of material, bodies; that a thing is what it appears to be; that our will is free; that what is good for me is also good in and for itself. Only very late did the deniers and doubters of such propositions emerge; only very late did truth emerge as the weakest form of knowledge. It seemed that one was unable to live with it; that our organism was geared for its opposite: all its higher functions, the perceptions of sense and generally every kind of sensation, worked with those basic errors that had been incorporated since time immemorial. Further, even in the realm of knowledge those propositions became the norms according to which one determined 'true' and 'untrue' - down to the most remote areas of pure logic. Thus the strength of knowledge lies not in its degree of truth, but in its age, its embeddedness, its character as a condition of life."

"From among the various conceptual schemes best suited to these various pursuits, one—the phenomenalistic—claims epistemological priority. Viewed from within the phenomenalistic conceptual scheme, the ontologies of physical objects and mathematical objects are myths. The quality of myth, however, is relative; relative, in this case, to the epistemological point of view. This point of view is one among various, corresponding to one among our various interests and purposes."

"There is a strange and wonderful reality out there, but until we devise an experiment that teaches us more than we presently know, it's better to embrace reality as we can measure it than to impose an additional structure driven by our own biases. Until we do that, we're superficially philosophizing about a matter where scientific intervention is required. Until we devise that key experiment, we'll all remain in the dark."

"The debate between scientific realists and anti-realists is one of the classics of philosophy of science, comparable to a soccer match between Brazil and Argentina."

"Hawking gives a good description of how scientists come to the conclusion that something is real: we construct intellectual models that, within some range of phenomena, and to some degree of approximation, agree with observation. But he calls this “model-dependent reality,” and suggests that this is all there is to reality. Questions about the nature of reality have puzzled scientists and philosophers for millennia. Like most people, I think that there is something real out there, entirely independent of us and our models, as the Earth is independent of our maps. But this is because I can’t help believing in an objective reality, not because I have good arguments for it. I am in no position to argue that Hawking’s antirealism is wrong. But I do insist that neither quantum mechanics nor anything else in physics settles the question."

"An anarchist is like an undercover agent who plays the game of Reason in order to undercut the authority of Reason (Truth, Honesty, Justice, and so on)."

"Some hold that fundamental ideas have changed so often within science—especially within physics—that we should always expect our current views to turn out to be wrong. Sometimes this argument is called the “pessimistic meta-induction.” The prefix “meta” is misleading here, because the argument is not an induction about inductions; it’s more like an induction about explanatory inferences. So let’s call it “the pessimistic induction from the history of science.” The pessimists give long lists of previously posited theoretical entities like phlogiston and caloric that we now think do not exist (Laudan 1981). Optimists reply with long lists of theoretical entities that once were questionable but which we now think definitely do exist—like atoms, germs, and genes."

"The pessimistic meta-induction seems to have some force in regard to fundamental physics: there, the change is much more rapid, and very little remains of past theories. … Non-fundamental concepts—such as cell or season—can survive significant shifts in fundamental theories, but obviously fundamental concepts like force or particle find it much more difficult to do so. … I think there is a view in the vicinity that is worth taking seriously: that we should be realists about non-fundamental science and at least somewhat skeptical of fundamental science."

"Alkimia Speculativa... treats of the generation of things from their elements, and of all inanimate things—as of the elements and liquids (humores) simple and compound; common stones, gems, and marbles; gold, and other metals; sulphur, salts, pigments, lapis lazuli, minium, and other colours; oils, bitumen, and very many other things—of which we find nothing in the books of Aristotle; nor are the natural philosophers or any of the Latins acquainted with these things. And being ignorant of them, they can know nothing of what follows in physics, that is, of the generation of animate things—as vegetables, animals, and man—because knowing not what is prior, they must remain ignorant of what is posterior. For the generation of men, and of brutes, and of plants, is from elemental and liquid substances, and is of like manner with the generation of inanimate things. Wherefore, through ignorance of this science, neither can natural philosophy... be known, nor the theory, and therefore neither the practice, of medicine; not merely because natural philosophy and theoretical medicine are necessary for the practice, but because all simple medicines are derived from inanimate things by this science."

"The word chemistry, in Greek should be wrote χημια, and in Latin and English chemia and chemistry; not as usual, chymia and chymistry. The first author in whom the word is found is Plutarch, who lived under the Emperors ', ', and '. That philosopher, in his treatise of ' and ', takes occasion to observe that Egypt, in the sacred dialect of the country, was called by the same name as the black of the eye viz., χημια—by which he seems to intimate that the word chemia in the Egyptian language signified black, and that the country, Egypt, might take its denomination from the blackness of the soil. ...Instead of black, some will have it originally denote secret, or occult; and hence derive it from the Hebrew chaman, or '—a mystery, whose radix is cham. And, accordingly, Plutarch observes that Egypt, in the same sacred dialect, is sometimes wrote in Greek χαμια—chamia; whence the word is easily deduced further from Cham, eldest son of Noah, by whom Egypt was first peopled after the deluge, and from whom, in the Scripture style, it is called the land of Cham, or Chem. Now, that chaman, or haman, properly signifies secret appears from the same Plutarch, who, mentioning an ancient author named Menethes Sibonita, who had asserted that Amman and Hammon were used to denote the god of Egypt, Plutarch takes this occasion to observe that in the Egyptian language anything secret or occult was called by the same name, αμμον—Hammon... Lastly, the learned Bochart, keeping to the same sense of the word, chooses to derive it from the Arabic chema, or kema—to hide; adding that there is an Arabic book of secrets called by the same name Kemi."

"Chemistry as an earnest and respectable science is often said to date from 1661, when Robert Boyle of Oxford published The Sceptical Chymist — the first work to distinguish between chemists and alchemists — but it was a slow and often erratic transition. Into the eighteenth century scholars could feel oddly comfortable in both camps — like the German Johann Becher, who produced sober and unexceptionable work on mineralogy called Physica Subterranea, but who also was certain that, given the right materials, he could make himself invisible."

"We must not forget that when was discovered no one knew that it would prove useful in hospitals. The work was one of pure science. And this is a proof that scientific work must not be considered from the point of view of the direct usefulness of it. It must be done for itself, for the beauty of science, and then there is always the chance that a scientific discovery may become like the radium a benefit for humanity."

"By convention (νόμῳ) sweet is sweet, by convention bitter is bitter, by convention hot is hot, by convention cold is cold, by convention color is color. But in reality there are atoms and the void. That is, the objects of sense are supposed to be real and it is customary to regard them as such, but in truth they are not. Only the atoms and the void are real."

"Even though Mendeleev always denied that electrons exist, they later turned out to be vital for ordering the elements in his table."

"I need only remind you of Davy's great researches: nitrous oxide; electric conduction and decomposition—resulting, on the one hand, in the separation of potassium and sodium, the decomposition of the earths following as a necessary consequence, and on the other in the electro-chemical theory; iodine and chlorine—resulting in the extension and confirmation of the word element, the discovery of the so-called hydrogen acids, and the important modification of the French theory of the constitution of acids; the investigation of gaseous explosion and of flame, and the invention of the safety lamp. These are the contributions to science which stand out more prominently in connection with Davy. But over and above all this is the peculiar manner of his discoveries. He was no patient plodder. He did not elaborate his work in minute detail. He dashed it off in broad masses; but just on that account there has never been anyone to follow up his investigations. Davy's mantle fell on no one, not even on Faraday."

"The laws of thermodynamics, as empirically determined, express the approximate and probable behavior of systems of a great number of particles, or, more precisely, they express the laws of mechanics for such systems as they appear to beings who have not the fineness of perception to enable them to appreciate quantities of the order of magnitude of those which relate to single particles, and who cannot repeat their experiments often enough to obtain any but the most probable results."

"We avoid the gravest difficulties when, giving up the attempt to frame hypotheses concerning the constitution of matter, we pursue statistical inquiries as a branch of rational mechanics."

"The distinction would only come to Mendeleev halfway through writing his Principles of Chemistry. ...chemical practice and not chemical theory had provided his initial organizing principle... Up to this point [Chapter 20], Mendeleev had only treated four elements in any detail: oxygen, carbon, nitrogen, and hydrogen—the so-called "organogens." Mendeleev began this chapter as usual by purifying the central substance, sodium chloride, from sources such as seawater. A discussion of sodium and chlorine followed in the next few chapters, and finally the halogens appeared... that were closely related to chlorine... and the alkali metals (the sodium family) form the first chapter of volume 2. ...he had dealt with only 8 elements, relegating 55... to the second volume. ...Mendeleev's earlier system of pedalogically useful organization—using laboratory practices... could no longer sustain the burden of exposition. He needed a new system... and he hit upon the idea of using a numerical marker for each element. Atomic weight seemed the most likely candidate for a system that would (a) account for all remaining elements; (b) do so in limited space; and (c) maintain some pedagogical merit. His solution, the periodic system, remains one of the most useful tools in chemistry."

"Why were Priestley, Boyle and Black able to see the question clearly enough to begin trying to answer it? ...because they had new tools. The air pump designed by Otto von Guericke and Boyle (...in collaboration with his assistant Robert Hooke...) were essential to Priestley's lab in Leeds. ...In a way, the air pump had enabled the entire field of pneumatic chemistry in the seventeenth century."

"In 1774 he thought he had obtained ... in 1775 he saw the gas as dephlogisticated air... If we refuse the palm to Priestley, we cannot award it to Lavoisier for the work of 1775... Lavoisier insisted that oxygen was an atomic "principle of acidity"... formed only when that "principle" united with "caloric"... Ignoring Scheele, we can safely say that oxygen had not been discovered before 1774, and we would probably say that it had been discovered by 1777 or shortly thereafter. But... any attempt to date the discovery must inevitably be arbitrary because discovering a new sort of phenomenon is necessarily a complex event, one which involves recognizing both that something is and what it is."

"In writing a textbook of general chemistry, Mendeleev devoted separate chapters to families of elements with similar properties, including the alkali metals, the alkaline earth metals, and the halogens. Reflecting on the properties of these and other elements, he proposed in 1869 a primitive version of today's periodic table. Indeed, he predicted detailed properties for three such elements (scandium, gallium, and germanium). By 1886 all of these elements had been discovered and found to have properties very similar to those he had predicted."

"[C]hemistry has always been as much about the making of products as it has been about discovering and scientifically explaining natural knowledge. It has always contained both craft and scientific components. In contemporary research in the history of chemistry, the science of chemistry is being recognized in its full extent."

"The law of conservation of mass was first put into definite form by Lavoisier, in the eighties of the eighteenth century. In considering the fermentation of fruit-juices, wherein carbonic acid gas and alcohol are produced, Lavoisier said:—"We must evidently have a complete knowledge of the analyses and the nature of the substances which can be fermented; for nothing is created, either in the operations of art, or in those of nature, and it may be laid down as a principle that, in every operation there is an equal quantity of matter before and after the operation; ...there is nothing but certain changes, certain modifications. The whole art of experimenting in chemistry rests on this principle; in all experiments one is obliged to assume an actual equality between the principles [that is, elements] of the substances examined and those obtained by the analysis of these substances. Thus, inasmuch as grape-juice yields carbonic acid gas and alcohol, I can affirm that grape juice=carbonic acid gas+alcohol.""

"The extension of Black's method by the physicist Lavoisier led to the downfall of the purely qualitative theory of phlogiston, and gave to chemistry the true methods of investigation, and its first great quantitative law—the law of conservation of matter."

"On the one hand, the student has been informed by some writers that the only certain way lies in the use of the entropy-function and the thermodynamic potentials; on the other hand, he is told with equal authority that the method used by the original investigators has been the consideration of cyclic processes, and that the former method is nothing but a mathematical (perhaps unnecessary) refinement of the results obtained by the latter. These extreme attitudes appear to me to be unfortunate, and more especially when one observes the physical clearness introduced by the use of cyclic processes, but at the same time remembers that most of the results obtained by separate investigators using cyclic processes had, with a great many more, previously been found by J. Willard Gibbs by means of a purely analytical method."

"There exists in Egypt a wonderful method of dyeing. The white cloth is stained in various places, not with dye stuffs, but with substances which have the property of absorbing (fixing) colours, these applications are not visible upon the cloth; but when they are dipped into a hot caldron of the dye they are drawn out an instant after dyed. The remarkable circumstance is, that though there be only one dye in the vat, yet different colours appear upon the cloth; nor can the colour be afterwards removed."

"Pliny the Elder, ' (AD 77) as quoted by Thomas Thomson, The History of Chemistry (1830) Vol. 1, and as on p. 93 of the (1835) 2 volume edition, where he adds, "It is evident that these substances applied were different which served to fix the dye upon the cloth...""

"It will be seen that my apparatus for experiments on air is in fact nothing more than that of Dr. Hales, Dr. Brownrigg, and Mr. Cavendish, diversified and made a little more simple."

"It was in consequence of living for some time in the neighbourhood of a public brewery, a little after Midsummer in 1767, that I was induced to make experiments on fixed air..."

"Dimitri was writing a textbook and wanted to organize the elements properly. So he wrote each element onto its own card to help him sort them out. Dimitri enjoyed playing cards, especially patience, and one evening he dosed off while working. He had a dream in which each of the cards lined up in rows, just like a game of patience. When he woke, he realized that he should put the elements in order of atomic mass."

"I have... hinted at the probability that Boyle himself was involved only in a very limited way in 'his' experimental manipulations. The device which became known as the machina Boyleana [air pump] was almost certainly constructed for him by remunerated assistants Ralph Greatorex and Robert Hooke, and even the extent of Boyle's rule in its evolving design remains unclear. The glass J-shaped tube that yielded his law of pressures and volumes was again almost certainly made for him and had to be manipulated by him in collaboration with assistants, if not solely by them. The furnaces in his laboratory, and the alembics in which long-term distillations were performed, were probably tended by assistants."

"The emphasis on the role of 'spirits' in chemical processes helps to explain why the alchemists placed so much importance on . For, by distillation, one could drive off the 'spiritual' part of a body and collect it separately in a pure form. In this way the ancient techniques of the perfumiers acquired a new theoretical significance. The oils and perfumes driven off when rose-petals were boiled in a closed vessel appeared to to embody the very soul (or essence or attar) of the original plant. This is in fact how phrases like 'essential oils' and 'vanilla essence' originated."

"[M]etals remained the alchemists' chief concern... they seemed in their own way alive, whereas the calces (s) from which they were manufactured crumbled to dust and looked like cinders. Theory at once suggested a natural analogy. The metal was formed from the calx by the incorporation of or spirit; and this theory of metal-formation long remained in favour, being revived around 1700 as the 'phlogiston' theory. The central problem about metals was to identify the volitile constituents which combined with the calces to form the finished metal. For a long time, the status of quicksilver was ambiguous... resembling much more the volitile reagents which corrode metallic surfaces: mercury, in fact, forms an amalgam with other metals, and is even capable of dissolving gold... So the Alchemy of Avicenna classed mercury as a 'spirit' rather than a 'body'..."

"It is a maxim universally admitted in geometry, and indeed in every branch of knowledge, that, in the progress of investigation, we should proceed from known facts to what is unknown. ...In this manner, from a series of sensations, observations, and analyses, a successive train of ideas arises, so linked together, that an attentive observer may trace back to a certain point the order and connection of the whole sum of human knowledge."

"We may lay it down as an incontestible axiom, that, in all the operations of art and nature, nothing is created; an equal quantity of matter exists both before and after the experiment; the quality and quantity of the elements remain precisely the same; and nothing takes place beyond changes and modifications in the combination of these elements. Upon this principle the whole art of performing chemical experiments depends: We must always suppose an exact equality between the elements of the body examined and those of the products of its analysis."

"Chemistry is a French science. It was founded Lavoisier, of immortal memory."

"For ages, it had been nothing but a collection of obscure receipts, often fallacious, used by the Alchemists, and afterwards by the Iatrochemists."

"Vainly had a great mind, George Ernest Stahl, endeavoured, at the commencement of the eighteenth century, to give it a scientific foundation. His system could not stand the test of facts or the searching criticism of Lavoisier."

"Lavoisier... was at once the author of a new theory and the creator of the true method in chemistry; and the superiority of the method gave wings to the theory. Sprung from exact observation of the phenomena of combustion, this theory was able to embrace all important facts known at that epoch. It had within itself both exactness and scope; it has become a system."

"[A] part of the science remained beyond... reach... which was more especially applicable to inorganic compounds. Organic chemistry was at that time limited to the qualitative description of principles extracted from products of vegetable and animal origin. The genius of discovery had indeed amassed a quantity of precious materials; but the science, which was to co-ordinate them, was not yet born. The very elements of this co-ordination... could be furnished only by the study of the metamorphoses of organic compounds."

"To discover the atomic constitution of organic compounds, and thereby to explain their properties, and establish their relations, is the object of Organic Chemistry... attained by determining the nature and number of the constituent atoms of organic compounds, and by studying their modes of formation and transformation. This great work was not really begun till about... 1830; but from that time it has been carried on with vigour and success."

"[S]ince the time of Lavoisier, the wealth of the science has been increased a hundredfold. Hence, the frame in which that great genius enclosed his system has become too narrow."

"Is it... astonishing that theories suggested by the study of organic compounds, and at first restricted within [that] domain... have taken wing, and striven to clear the bounds which separate organic from mineral chemistry? ...[T]hey now embrace the whole field of the science; and, thanks to them... there is but one chemistry."

"So great a result is not the work of one day or the conquest of a revolution; it is the result of slow and continued progress. But if we... carry our ideas back to the starting-point, we must avow that the progress is immense. Compared with the science of that time, the science of the present day appears to us not only enlarged, but transformed and regenerated."

"Is it complete, as regards its doctrines; and are the new paths... made altogether plain? We do not think so. But the greatness of the advance permits us to affirm that the roads are good. We may then halt for a moment, and, casting our eyes over the distance already traversed, mark with certainty the point at which we have arrived."

"This History has been written because of a conviction, from my own experience and experience with my students, that one of the best aids to an intelligent comprehension of the science of chemistry is the study of the long struggle, the failures, and the triumphs of the men who have made this science for us."

"Free use has been made of all the chief authorities; the historical works of Kopp, Berthelot, Hoefer, Thomson, Ernst v. Meyer, Ladenburg, Rodwell, Muir, Wurtz, Hartmann, Gmelin, Karmarsch, and Siebert, besides the original works of nearly all the chemists mentioned for the past century and a half, have been consulted."

"The ovum from which chemistry has been slowly evolved seems to have been sorcery and magic."

"The word χημεία occurs first in the writings of , a Greek lexicographer of the eleventh century. It is there defined as the "preparing of gold and silver." This is manifestly a Greek rendering of the name Chema or Chemi, which is of Egyptian origin, and all attempts at deriving it from χεω, to fuse, or χνμα a liquid, are without import."

"Plutarch tells us that Chemia was a name given Egypt on account of the black soil, and that this term further meant the black of the eye, symbolizing that which was obscure and hidden."

"The Coptic word khems or chems is closely related to this, and also signifies obscure, occult, and with this is connected the Arabic word chema, to hide."

"It is therefore the occult or hidden science, the black art."

"Two difficulties meet one in studying the early history of the science. One is... mysticism... and the other is the custom among the early writers of ascribing their discoveries, books, etc., to fabulous names or ancient heroes and gods. This latter had two objects, the first being to shield the true author in time of persecution, and the second to gain a certain amount of credit and reputation... by the use of the names of such celebrities as Moses, Solomon, Alexander, or Cleopatra. This tendency is especially noticeable among the writers of the Middle Ages, and also the early Greek authors, and is not peculiar to authors of alchemical treatises."

"No original manuscript of the earliest writers on chemistry or alchemy has been discovered. Our knowledge must be gleaned from the pages of those writing upon other subjects, or must come from fragments handed down to us through several copyists."

"The reason generally assigned for this absence of early records is that burned all writings of the Egyptians bearing upon alchemy, because, as he said, these taught the art of making gold and silver; and, by destroying them, he took away from the Egyptians the power of enriching themselves and rebelling against the Romans."

"[T]he Chinese... had... knowledge of metals, alloys, colors, and salts for a long time, and that they manufactured gun powder and porcelain before they were known in Europe."

"In... India... knowledge of the extraction of metals, the making of steel, the preparation of colors, and similar technical operations, dates back to the most remote antiquity. They also theorized as to the elements and their number. Their synonym for death was, "man returns to the five elements.""

"The almost universal tradition among alchemists is that their art was first cultivated among the Egyptians, and that , the Egyptian god of arts and sciences, was its founder. The finding of papyri of a chemical nature in the tombs... lead us to give credence to this tradition... Clement of Alexandria tells us that the knowledge... was restricted to the priests, who were forbidden to communicate it... Plutarch also mentions the strict secrecy observed, and the cloaking... under the guise of fables."

"[T]here is a similarity easily detected between the hieroglyphics and the alchemical signs. The phraseology in the early treatises is similar to that in the priestly writings."

"[N]ote the important part played by the number four with the alchemists as well as with the Egyptian priests. There are the four bases or elements, the tetrasomy of ; the four zones, four funeral deities, four cardinal points, four winds, four colors, etc."

"The ns, as masters of occult sciences, played an important part at Rome. In much earlier times, the Bible mentions them as the depositaries of all wisdom and science... They were rivals of the Egyptians in knowledge, and were especially famous as astrologers. Many industrial arts were brought to as high perfection in as in Egypt; for instance, the processes of glass-making, of dyeing, and of working in metals. Those Chaldeans who settled in Rome in later years came from Syria and . Tacitus makes mention of them. They were much sought after by the fashionable as the representatives of Eastern religions and mystic doctrines."

"Ostanes, the Mede, was one of the celebrated early alchemists. Several writers have recorded for us the existence of a book called The Book of the Divine Prescriptions, which seems to have been the most famous writing of these Persian sages."

"The belief in some wonderful connection between planets and metals is due to these ns. The signs of the heavenly bodies became the symbols for the metals. These planets influenced a supposed growth of the metals, and were esteemed all-powerful in regulating human life and fate. Many of these notions are to be attributed to the Alexandrian epoch."

"Observations of the changes which are constantly happening in the sky, and on the earth, must have prompted men long ago to ask whether there are any limits to the changes of things around them. And this question must have become more urgent as working in metals, making colours and dyes, preparing new kinds of food and drink, producing substances with smells and tastes unlike those of familiar objects, and other pursuits like these, made men acquainted with transformations which seemed to penetrate to the very foundations of things."

"Some of the Greek philosophers who lived four or five hundred years before Christ formed a theory of the transformations of matter, which is essentially the theory held by naturalists to-day. ...Those investigators attempted to connect all the differences which are observed between the qualities of things with differences of size, shape, position, and movement of atoms... unchangeable, indestructible, and impenetrable particles ...not one of them can be destroyed, nor can one be created; when a substance ceases to exist and another is formed, the process is not a destruction of matter, it is a re-arrangement of atoms."

"The first principle in nature is asserted by Lucretius [Concerning the Nature of Things] to be that " Nothing is ever gotten out of nothing.""

"We now know that many compounds exist which are formed by the union of the same quantities by weight of the same elements, and, nevertheless, differ in properties; modern chemistry explains this fact by saying that the properties of a substance depend, not only on the kind of atoms which compose the minute particles of a compound, and the number of atoms of each kind, but also on the mode of arrangement of the atoms. The same doctrine was taught by Lucretius, two thousand years ago. " It often makes a great difference," he said, " with what things, and in what positions the same first beginnings are held in union, and what motions they mutually impart and receive.""

"Lucretius pictured a solid substance as a vast number of atoms squeezed closely together, a liquid as composed of not so many atoms less tightly packed, and a gas as a comparatively small number of atoms with considerable freedom of motion. Essentially the same picture is presented by the molecular theory of to-day."

"Another objector urges—"You say the atoms are always moving, yet the things we look at, which you assert to be vast numbers of moving atoms, are often motionless." ...Lucretius answers by an analogy. " And herein you need not wonder at this, that... since they are themselves beyond what you can see, they must withdraw from sight their motion as well; and the more so, that the things which we can see do yet often conceal their motions when a great distance off.""

"More than two thousand years passed before investigators began to make accurate measurements of the quantities of the substances which take part in those changes wherein certain things seem to be destroyed and other totally different things to be produced; until accurate knowledge had been obtained of the quantities of the definite substances which interact in the transformations of matter, the atomic theory could not do more than draw the outlines of a picture of material changes. A scientific theory has been described as "the likening of our imaginings to what we actually observe." So long as we observe only in the rough, only in a broad and general way, our imaginings must also be rough, broad, and general."

"The atomic theory was used by the great physicists of the later Renaissance, by Galileo, Gassendi, Newton and others. ... John Dalton, while trying ...to form a mental presentation of the atmosphere in terms of the theory of atoms, rediscovered the possibility of differences between the sizes of atoms, applied this idea to the facts concerning the quantitative compositions of compounds which had been established by others, developed a method for determining the relative weights of atoms of different kinds, and started chemistry on the course which it has followed so successfully."

"[M]any chemical facts, products, and processes have been known from a period considerably earlier than any of which we have a historic record. As a true science... chemistry is only between one and two hundred years old... but... it has been known and practised as an art continuously since prehistoric times. The skilled, and often royal or priestly, artisans handed down its secrets in the shape of workshop traditions, from the earliest ages till the present day..."

"The origin of the science of chemistry must... be sought in the art of alchemy. ...[I]n the course of their labours they gained much definite information regarding the properties of metals and other substances, devised the necessary apparatus and processes for chemical operations, and laid a foundation upon which later investigators have built up the modern science."

"[T]he Alchemical Period... may with propriety be called "The Ancient History of Chemistry.""

"The application of the term [alchemy] has frequently but wrongfully been restricted to the pretended arts of making gold and silver, and the more profitable arts of adulterating and of imitating gold. It had, however, a wider application, and ought to be regarded as including all the arts known in ancient times which dealt with things now comprehended in the science of chemistry."

"The use of the expression "chemist" to indicate a druggist reminds us of another branch of alchemy, the art of making drugs which received much attention in Ancient Egypt, and probably in other eastern countries, and was combined with the art of preparing poisons and their antidotes."

"The ancient Egyptians... had a profound knowledge of the art of making, tinting, and working glass."

"The arts and industries of dyeing, painting, and staining were known and practised in eastern lands in very ancient times. ...[T]he dyeing of skins and garments... is mentioned in most writings of antiquity. The colours used in early Egyptian art remain bright and clear. ...Remains found in Chaldea include coloured articles, as well as articles made of metal."

"We are apt to suppose that the use of s is of modern origin, but that is not so. Not only did the Hebrews and the Greeks employ antiseptics in their religious rites, but in Egypt a very high degree of skill must have been attained in their preparation and use, before the body of King Rameses... and hundreds of others could have been preserved for between three and four thousand years so perfectly..."

"The development of the paraffin and other hydrocarbon industries during the present generation may make us fancy that this is a modern discovery; but it is the fact that the fire on the Hebrew altar fed by the Jewish priests was our familiar petroleum and was called r or nephi, a Hebrew word signifying purification..."

"[T]he first period [prehistory to 500 B.C.] into which the history of chemistry naturally divides itself is that during which a number of chemical facts were known, but not understood or explained. These facts were not correlated, nor was the subject studied with scientific purpose and method, consequently during this period chemistry was not a science."

"The Greeks were no chemists. The bent of their mind was not towards natural science; few observations or experiments were made by them, and they preferred to argue from general principles to particulars, rather than from particular observations to general principles."

"Davy held that if the battery is strong enough any compound may be decomposed, and that chemical affinity is merely a form of electric attraction. He vigorously put his theory into practice..."

"Berthollet's conclusion that chlorine is oxymuriatic acid was universally accepted until Gay-Lussac and Thénard in 1809 endeavoured to decompose the gas and failed. They concluded that it contained water because it yielded water when passed over litharge. Their researches read to the Institute in 1809 led Davy to investigate muriatic acid (hydrochloric acid) gas, which in 1808 he had shown to be decomposed by potassium, with evolution of hydrogen. In 1810 he proved that chlorine is an element, and that muriatic acid gas is a compound of chlorine and hydrogen. He thus overturned the oxygen-acid theory, and demonstrated that muriates are compounds of metals with chlorine. He pointed to the fact that some acids, such as sulphuretted hydrogen, contain no oxygen, and argued that muriatic acid gas was one of these, chlorine in it taking the place of oxygen. ...The conclusions of Davy were at first doubted, but when iodine and bromine were also discovered, Gay-Lussac and his followers adopted Davy's views. The latter worked out fluorine, and proved that hydrofluoric acid (HF) contains no oxygen. Berzelius also opposed Davy until the discovery of iodine, but embraced the latter's opinion in 1820."

"The fantastic 12-digit agreement between the theoretical predictions of QED and the experimental results is a miracle. It would be good for physicists to acknowledge the unsatisfactory mathematical structure of this prediction. It starts from a mathematically undefined Feynman Integral, proceeds by making many very complicated manipulations, and ends up with a formal series that Dyson showed to be divergent! Physicists think of it as an asymptotic expansion, but they have no mathematical proof of this. I often joke that this agreement of theory and experiment is a new proof of the existence of God and that she loves physicists!"

"I claim that the success of current scientific theories is no miracle. It is not even surprising to the scientific (Darwinist) mind. For any scientific theory is born into a life of fierce competition, a jungle red in tooth and claw. Only the successful theories survive—the ones which in fact latched onto the actual regularities in nature."

"Realism is not a dirty word. If you wonder why all scientists, philosophers, and ordinary people, with rare exceptions, have been and are unabashed realists, let me tell you why. No scientific conjecture has been more overwhelmingly confirmed. No hypothesis offers a simpler explanation of why the Andromeda galaxy spirals in every photograph, why all electrons are identical, why the laws of physics are the same in Tokyo as in London or on Mars, why they were there before life evolved and will be there if all life perishes, why all persons can close their eyes and feel eight corners, six faces and twelve edges on a cube, and why your bedroom looks the same when you wake up in the morning."

"Not merely trainee and professional members of the medical profession commit the base-rate fallacy. Even very eminent scientists do, as we have seen. And all the philosophers who use the No-Miracles argument do so as well."

"The positive argument for realism is that it is the only philosophy that doesn't make the success of science a miracle."

"The main reason for believing scientific theories (at least the bestverified ones) is that they explain the coherence of our experience. Let us be precise: here ‘experience’ refers to all our observations, including the results of laboratory experiments whose goal is to test quantitatively (sometimes to incredible precision) the predictions of scientific theories. … This agreement between theory and experiment, when combined with thousands of other similar though less spectacular ones, would be a miracle if science said nothing true – or at least approximately true – about the world. The experimental confirmations of the best-established scientific theories, taken together, are evidence that we really have acquired an objective (albeit approximate and incomplete) knowledge of the natural world."

"From causes which appear similar we expect similar effects. This is the sum of all our experimental conclusions. Now it seems evident that, if this conclusion were formed by reason, it would be as perfect at first, and upon one instance, as after ever so long a course of experience. But the case is far otherwise. Nothing so like as eggs; yet no one, on account of this appearing similarity, expects the same taste and relish in all of them. It is only after a long course of uniform experiments in any kind, that we attain a firm reliance and security with regard to a particular event. Now where is that process of reasoning which, from one instance, draws a conclusion, so different from that which it infers from a hundred instances that are nowise different from that single one? This question I propose as much for the sake of information, as with an intention of raising difficulties. I cannot find, I cannot imagine any such reasoning."

"Domestic animals expect food when they see the person who usually feeds them. We know that all these rather crude expectations of uniformity are liable to be misleading. The man who has fed the chicken every day throughout its life at last wrings its neck instead, showing that more refined views as to the uniformity of nature would have been useful to the chicken."

"The riddle of induction can be put thus: What rational basis is there for any of our beliefs about the unobserved? The theory of personal probability touches on the domain of the riddle and can even be construed as giving a partial answer. The theory prescribes, presumably compellingly, exactly how a set of beliefs should change in the light of what is observed. It can help you say, "My opinions today are the rational consequence of what they were yesterday and of what I have seen since yesterday." In principle, yesterday's opinions can be traced to the day before, but even given a coherent demigod able to trace his present opinions back to those with which he was born and to what he has experienced since, the theory of personal probability does not pretend to say with what system of opinions he ought to have been born. It leaves him, just as Hume would say, without rational foundation for his beliefs of today. Can there be any such foundation? The theory as such is silent, but I am led by study of it to doubt that there is a rational basis for what we believe about the unobserved. In fact, Hume's arguments, and modern variants of them such as Goodman's discussion of 'bleen' and 'grue', appeal to me as correct and realistic. That all my beliefs are but my personal opinions, no matter how well some of them may coincide with opinions of others, seems to me not a paradox but a truism. The grandiose image of a demigod tracing his beliefs back to the cradle only to find an impasse there seems a valid metaphor. If there is rational basis for beliefs going beyond mere coherency, then there are some specific opinions that a rational baby demigod must have. Put that way, the notion of any such basis seems to me quite counterintuitive."

"The borderlines between genuine science and pseudoscience may be fuzzy, but this should be even more of a call for careful distinctions, based on systematic facts and sound reasoning. To try a modicum of turtle blood here and a little aspirin there is not the hallmark of wisdom and even-mindedness. It is a dangerous gateway to superstition and irrationality."

"What is found in biology is mechanisms, mechanisms built with chemical components and that are often modified by other, later, mechanisms added to the earlier ones. While is a useful tool in the physical sciences, it can be a very dangerous implement in biology."

"A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended its area of applicability."

"Men see with arrogant eyes which organize everything seen with reference to themselves and their own interests. ...Western philosophy and science have for the most part been committed to the Simplicity Theory of Truth: the simplest theory that accounts for the data is the true theory. (Theories are simplest which postulate the fewest entities, require the fewest hypotheses, generate predictions by the fewest calculations, etc.) ...If someone believes that the world is made for him to have dominion over and he is made to exploit it, he must believe that he and the world are so made that he can, at least in principle, achieve and maintain dominion over everything. But you can’t put things to use if you don’t know how they work. So he must believe that he can, at least in principle, understand everything. If the world exists for man, it must be usably intelligible, which means it must be simple enough for him to understand. A usable universe is an intelligible universe is a simple universe. ...And so it goes with the philosophy and the science of The Arrogant Eye."

"Nobody knows how many universes there are. Theory places no limit: any and all possibilities in unlimited number of combinations of "natural" laws, each sheaf appropriate to its own universe. But this is just theory and Occam's Razor is much too dull."

"The principle of simplicity is the central theme of Ockham’s approach, so much so that this principle has come to be known as “Ockham’s Razor.” Ockham uses the razor to eliminate unnecessary hypotheses."

"Numquam ponenda est pluralitas sine necessitate."

"There never was a sounder logical maxim of scientific procedure than Ockham's razor: Entia non sunt multiplicanda praeter necessitatem. That is to say; before you try a complicated hypothesis, you should make quite sure that no simplification of it will explain the facts equally well. No matter if it takes fifty generations of arduous experimentation to explode the simpler hypothesis, and no matter how incredible it may seem that that simpler hypothesis should suffice, still fifty generations are nothing in the life of science, which has all time before it; and in the long run, say in some thousands of generations, time will be economized by proceeding in an orderly manner, and by making it an invariable rule to try the simpler hypothesis first. Indeed, one can never be sure that the simpler hypothesis is not the true one, after all, until its cause has been fought out to the bitter end. But you will mark the limitation of my approval of Ockham's razor. It is a sound maxim of scientific procedure. If the question be what one ought to believe, the logic of the situation must take other factors into account. Speaking strictly, belief is out of place in pure theoretical science, which has nothing nearer to it than the establishment of doctrines, and only the provisional establishment of them, at that. Compared with living belief it is nothing but a ghost. If the captain of a vessel on a lee shore in a terrific storm finds himself in a critical position in which he must instantly either put his wheel to port acting on one hypothesis, or put his wheel to starboard acting on the contrary hypothesis, and his vessel will infallibly be dashed to pieces if he decides the question wrongly, Ockham's razor is not worth the stout belief of any common seaman. For stout belief may happen to save the ship, while Entia non sunt multiplicanda praeter necessitatem would be only a stupid way of spelling Shipwreck. Now in matters of real practical concern we are all in something like the situation of that sea-captain."

"Structural realism—in its metaphysical version, championed by the philosopher of science James Ladyman—is the deepest explanation I know, because it serves as a kind of meta-explanation, one that explains the nature of reality and the nature of scientific explanations."

"This reality crisis has grown so dire that Stephen Hawking has called for a kind of philosophical surrender, a white flag he terms "model-dependent realism", which basically says that while our theoretical models offer possible descriptions of the world, we'll simply never know the true reality that lies beneath. Perhaps there is no reality at all. But structural realism offers a way out. An explanation. A reality. The only catch is that it's not made of physical objects. Then again, our theories never said it was. Electrons aren't real, but the mathematical structure of quantum field theory is. Gauge forces aren't real, but the symmetry groups that describe them are. The dimensions, geometries and even strings described by any given string theory aren't real—what's real are the mathematical maps that transform one string theory into another."

"Weirdly, although the beauty of physical theories is embodied in rigid mathematical structures based on simple underlying principles, the structures that have this sort of beauty tend to survive even when the underlying principles are found to be wrong. A good example is Dirac’s theory of the electron. Dirac in 1928 was trying to rework Schrödinger’s version of quantum mechanics in terms of particle waves so that it would be consistent with the special theory of relativity. This effort led Dirac to the conclusions that the electron must have a certain spin, and that the universe is filled with unobservable electrons of negative energy, whose absence at a particular point would be seen in the laboratory as the presence of an electron with the opposite charge, that is, an antiparticle of the electron. His theory gained an enormous prestige from the 1932 discovery in cosmic rays of precisely such an antiparticle of the electron, the particle now called the positron. Dirac’s theory was a key ingredient in the version of quantum electrodynamics that was developed and applied with great success in the 1930s and 1940s. But we know today that Dirac’s point of view was largely wrong. […] Yet the mathematics of Dirac’s theory has survived as an essential part of quantum field theory; it must be taught in every graduate course in advanced quantum mechanics. The formal structure of Dirac’s theory has thus survived the death of the principles of relativistic wave mechanics that Dirac followed in being led to his theory. So the mathematical structures that physicists develop in obedience to physical principles have an odd kind of portability. They can be carried over from one conceptual environment to another and serve many different purposes, like the clever bones in your shoulders that in another animal would be the joint between the wing and the body of a bird or the flipper and body of a dolphin. We are led to these beautiful structures by physical principles, but the beauty sometimes survives when the principles themselves do not."

"It is important to keep straight what does and what does not change in scientific revolutions, a distinction that is not made in Structure. There is a "hard" part of modern physical theories ("hard" meaning not difficult, but durable, like bones in paleontology or potsherds in archeology) that usually consists of the equations themselves, together with some understandings about what the symbols mean operationally and about the sorts of phenomena to which they apply. Then there is a "soft" part; it is the vision of reality that we use to explain to ourselves why the equations work. The soft part does change; we no longer believe in Maxwell's ether, and we know that there is more to nature than Newton's particles and forces. The changes in the soft part of scientific theories also produce changes in our understanding of the conditions under which the hard part is a good approximation. But after our theories reach their mature forms, their hard parts represent permanent accomplishments. If you have bought one of those T-shirts with Maxwell's equations on the front, you may have to worry about its going out of style, but not about its becoming false. We will go on teaching Maxwellian electrodynamics as long as there are scientists. I can't see any sense in which the increase in scope and accuracy of the hard parts of our theories is not a cumulative approach to truth."

"δῶς μοι πᾶ στῶ καὶ τὰν γᾶν κινάσω."

"One needs occasionally to stand aside from the hum and rush of human interests and passions to hear the voices of God. And it not unfrequently happens that the All-loving gives a great push to certain souls to thrust them out, as it were, from the distracting current for awhile to promote their discipline and growth, or to enrich them by communion and reflection. And similarly it may be woman's privilege from her peculiar coigne of vantage as a quiet observer, to whisper just the needed suggestion or the almost forgotten truth. The colored woman, then, should not be ignored because her bark is resting in the silent waters of the sheltered cove. She is watching the movements of the contestants none the less and is all the better qualified, perhaps, to weigh and judge and advise because not herself in the excitement of the race."

"Make Christianity your own, and it will show you a point outside the world, and by means of this you will move heaven and earth."

"Soweit es sich hier um „Paria"-Intellektualismus handelt, ... beruht dessen Intensität darauf, daß die außerhalb oder am unteren Ende der sozialen Hierarchie stehenden Schichten gewissermaßen auf dem archimedischen Punkt gegenüber den gesellschaftlichen Konventionen, sowohl was die äußere Ordnung wie was die üblichen Meinungen angeht, stehen. Sie sind daher einer durch jene Konvention nicht gebundenen originären Stellungnahme zum „Sinn" des Kosmos und eines starken, durch materielle Rücksicht nicht gehemmten, ethischen und religiösen Pathos fähig."

"There seems to be a vast landscape of possible universes. ... We live in one in which life is possible, but if the universe were only slightly different, beings like us could not exist. What are we to make of this fine-tuning? Is it evident that the universe, after all, was designed by a benevolent creator? Or does science offer a different explanation?"

"The old cosmological constant problem is to understand why the is so small; the new problem is to understand why it is comparable to the present mass density. ... does not help with either; anthropic considerations offer a possibility of solving both. In theories with a that takes random initial values, the anthropic principle may apply to the cosmological constant, but probably to nothing else."

"Once one starts to admit anthropic interpretations of fine-tuning problems like the cosmological constant, it is clear that such a proposal might be made for other fine-tuning problems, such as the problem of the Higgs boson mass. Certainly, we would not be here if the Higgs boson mass, and hence also the and and and masses, were greatly bigger. If they were near the , for example, any collection of more than a few elementary particles would collapse into a Black Hole. More generally, if the elementary particle masses were scaled up by a factor N, the number of elementary particles in a star or planet would scale down like N–3, and for very modest N the stars would stop shining."