All Quotes

"Some subjects are so serious that one can only joke about them."

"Truth and clarity are complementary."

"It is not enough to be wrong, one must also be polite."

"Never express yourself more clearly than you are able to think."

"Oh, what idiots we all have been. This is just as it must be."

"I go into the Upanishads to ask questions."

"No, no, you are not thinking, you are just being logical."

"I am absolutely prepared to talk about the spiritual life of an electronic computer: to state that it is reflecting or is in a bad mood... The question whether the machine really feels or ponders, or whether it merely looks as though it did, is of course absolutely meaningingless."

"I feel very much like Dirac: the idea of a personal God is foreign to me. But we ought to remember that religion uses language in quite a different way from science. The language of religion is more closely related to the language of poetry than to the language of science. True, we are inclined to think that science deals with information about objective facts, and poetry with subjective feelings. Hence we conclude that if religion does indeed deal with objective truths, it ought to adopt the same criteria of truth as science. But I myself find the division of the world into an objective and a subjective side much too arbitrary. The fact that religions through the ages have spoken in images, parables, and paradoxes means simply that there are no other ways of grasping the reality to which they refer. But that does not mean that it is not a genuine reality. And splitting this reality into an objective and a subjective side won't get us very far."

"I consider those developments in physics during the last decades which have shown how problematical such concepts as "objective" and "subjective" are, a great liberation of thought. The whole thing started with the theory of relativity. In the past, the statement that two events are simultaneous was considered an objective assertion, one that could be communicated quite simply and that was open to verification by any observer. Today we know that 'simultaneity' contains a subjective element, inasmuch as two events that appear simultaneous to an observer at rest are not necessarily simultaneous to an observer in motion. However, the relativistic description is also objective inasmuch as every observer can deduce by calculation what the other observer will perceive or has perceived. For all that, we have come a long way from the classical ideal of objective descriptions. In quantum mechanics the departure from this ideal has been even more radical. We can still use the objectifying language of classical physics to make statements about observable facts. For instance, we can say that a photographic plate has been blackened, or that cloud droplets have formed. But we can say nothing about the atoms themselves. And what predictions we base on such findings depend on the way we pose our experimental question, and here the observer has freedom of choice. Naturally, it still makes no difference whether the observer is a man, an animal, or a piece of apparatus, but it is no longer possible to make predictions without reference to the observer or the means of observation. To that extent, every physical process may be said to have objective and subjective features. The objective world of nineteenth-century science was, as we know today, an ideal, limiting case, but not the whole reality. Admittedly, even in our future encounters with reality we shall have to distinguish between the objective and the subjective side, to make a division between the two. But the location of the separation may depend on the way things are looked at; to a certain extent it can be chosen at will. Hence I can quite understand why we cannot speak about the content of religion in an objectifying language. The fact that different religions try to express this content in quite distinct spiritual forms is no real objection. Perhaps we ought to look upon these different forms as complementary descriptions which, though they exclude one another, are needed to convey the rich possibilities flowing from man's relationship with the central order."

"No more useful inquiry can be proposed than that which seeks to determine the nature and the scope of human knowledge. ... This investigation should be undertaken once at least in his life by anyone who has the slightest regard for truth, since in pursuing it the true instruments of knowledge and the whole method of inquiry come to light. But nothing seems to me more futile than the conduct of those who boldly dispute about the secrets of nature ... without yet having ever asked even whether human reason is adequate to the solution of these problems."

"In mathematics we can take our inner distance from the content of our statements. In the final analysis mathematics is a mental game that we can play or not play as we choose. Religion, on the other hand, deals with ourselves, with our life and death; its promises are meant to govern our actions and thus, at least indirectly, our very existence. We cannot just look at them impassively from the outside. Moreover, our attitude to religious questions cannot be separated from our attitude to society. Even if religion arose as the spiritual structure of a particular human society, it is arguable whether it has remained the strongest social molding force through history, or whether society, once formed, develops new spiritual structures and adapts them to its particular level of knowledge. Nowadays, the individual seems to be able to choose the spiritual framework of his thoughts and actions quite freely, and this freedom reflects the fact that the boundaries between the various cultures and societies are beginning to become more fluid. But even when an individual tries to attain the greatest possible degree of independence, he will still be swayed by the existing spiritual structures — consciously or unconsciously. For he, too, must be able to speak of life and death and the human condition to other members of the society in which he's chosen to live; he must educate his children according to the norms of that society, fit into its life. Epistemological sophistries cannot possibly help him attain these ends. Here, too, the relationship between critical thought about the spiritual content of a given religion and action based on the deliberate acceptance of that content is complementary. And such acceptance, if consciously arrived at, fills the individual with strength of purpose, helps him to overcome doubts and, if he has to suffer, provides him with the kind of solace that only a sense of being sheltered under an all-embracing roof can grant. In that sense, religion helps to make social life more harmonious; its most important task is to remind us, in the language of pictures and parables, of the wider framework within which our life is set."

"Prediction is very difficult, especially about the future."

"Stop telling God what to do with his dice."

"Of course not ... but I am told it works even if you don't believe in it."

"Everything we call real is made of things that cannot be regarded as real."

"We pretend that if I get result +1 here, immediately the photon there is in the state |x>, but if I find -1, immediately the other photon assume[s] another state of polarization... [T]his image is not acceptable for Einstein because it seems as [though] something is going . ...It is by this ...reasoning that Einstein said... "If you want to make sense of this correlation at a distance, you have to accept that before they arrive at the measuring apparatus, the particles have already a property determining the outcome." ...Bohr disagreed immediately. ...I don't know anybody who finds Bohr's reply understandable. It's not a joke, what I'm going to say, although it sounds [like] a joke. Bohr is so cautious in his wording that he makes it almost impossible to understand... Bohr insisted on complementarity, and at one point he declared... that "Clarity and truth are complementary," and he made all efforts to be as true as possible."

"Bohr seemed to think that he had solved this question. I could not find his solution in his writings. But there was no doubt that he was convinced that he had solved the problem and, in so doing, had not only contributed to atomic physics, but to epistemology, to philosophy, to humanity in general. And there are astonishing passages in his writings in which he is sort of patronizing to the ancient Far Eastern philosophers, almost saying that he had solved the problems that had defeated them. It's an extraordinary thing for me—the character of Bohr—absolutely puzzling. I like to speak of two Bohrs: one is a very pragmatic fellow who insists that the apparatus is classical, and the other is a very arrogant, pontificating man who makes enormous claims for what he has done."

"One of the favorite maxims of my father was the distinction between the two sorts of truths, profound truths recognized by the fact that the opposite is also a profound truth, in contrast to trivialities where opposites are obviously absurd."

"If quantum theory has any philosophical importance at all, it lies in the fact that it demonstrates for a single, sharply defined science the necessity of dual aspects and complementary considerations. Niels Bohr has discussed this question with respect to many applications in physiology, psychology, and philosophy in general."

"Not often in life has a human being caused me such joy by his mere presence as you did."

"It is practically impossible to describe Niels Bohr to a person who has never worked with him. Probably his most characteristic property was the slowness of his thinking and comprehension. When, in the late twenties and early thirties, the author of this book was one of the "Bohr boys" working in his Institute in Copenhagen on a Carlsberg (the best beer in the world!) fellowship, he had many a chance to observe it. In the evening, when a handful of Bohr's students were "working" in the Paa Blegdamsvejen Institute, discussing the latest problems of the quantum theory, or playing Ping-pong on the library table with coffee cups placed on it to make the game more difficult, Bohr would appear, complaining that he was very tired, and would like to "do something." To "do something" inevitably meant to go to the movies, and the only movies Bohr liked were those called The Gun Fight at the Lazy Gee Ranch or The Lone Ranger and a Sioux Girl. But it was hard to go with Bohr to the movies. He could not follow the plot, and was constantly asking us, to the great annoyance of the rest of the audience, questions like this: "Is that the sister of that cowboy who shot the Indian who tried to steal a herd of cattle belonging to her brother-in-law?" The same slowness of reaction was apparent at scientific meetings. Many a time, a visiting young physicist (most physicists visiting Copenhagen were young) would deliver a brilliant talk about his recent calculations on some intricate problem of the quantum theory. Everybody in the audience would understand the argument quite clearly, but Bohr wouldn't. So everybody would start to explain to Bohr the simple point he had missed, and in the resulting turmoil everybody would stop understanding anything. Finally, after a considerable period of time, Bohr would begin to understand, and it would turn out that what he understood about the problem presented by the visitor was quite different from what the visitor meant, and was correct, while the visitor's interpretation was wrong."

"I remember discussions with Bohr which went through many hours till very late at night and ended almost in despair; and when at the end of the discussion I went alone for a walk in the neighbouring park I repeated to myself again and again the question: Can nature possibly be so absurd as it seemed to us in these atomic experiments?"

"The first thing Bohr said to me was that it would only then be profitable to work with him if I understood that he was a dilettante. The only way I knew to react to this unexpected statement was with a polite smile of disbelief. But evidently Bohr was serious. He explained how he had to approach every new question from a starting point of total ignorance. It is perhaps better to say that Bohr's strength lay in his formidable intuition and insight rather than erudition."

"When asked whether the algorism of quantum mechanics could be considered as somehow mirroring an underlying quantum world, Bohr would answer, "There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature." Bohr felt that every step in the development of physics has strengthened the view that the problem of establishing an unambiguous description of nature has only one solution. He regarded all attempts to replace our elementary concepts or to introduce a new logic to account for the peculiarities of quantum phenomena as not merely unnecessary but also incompatible with our most fundamental conditions, since we are suspended in a unique language."

"[Bohr was] a marvelous physicist, one of the greatest of all time, but he was a miserable philosopher, and one couldn't talk to him. He was talking all the time, allowing practically only one or two words to you and then at once cutting in."

"A big, athletic man, a terrible writer and famous mumbler, Bohr was, after Einstein, the greatest physicist of the era, remarkable not only for his intuitive brilliance but for a kindness that extended equally to his friends and to humanity."

""You can talk about people like Buddha, Jesus, Moses, Confucius, but the thing that convinced me that such people existed were the conversations with Bohr," Dr. Wheeler said."

"Niels Bohr distinguished two kinds of truths. An ordinary truth is a statement whose opposite is a falsehood. A profound truth is a statement whose opposite is also a profound truth."

"Logic is the most useful tool of all the arts. Without it no science can be fully known. It is not worn out by repeated use, after the manner of material tools, but rather admits of continual growth through the diligent exercise of any other science. For just as a mechanic who lacks a complete knowledge of his tool gains a fuller [knowledge] by using it, so one who is educated in the firm principles of logic, while he painstakingly devotes his labor to the other sciences, acquires at the same time a greater skill at this art."

"The head of Christians does not, as a rule, have power to punish secular wrongs with a capital penalty and other bodily penalties and it is for thus punishing such wrongs that temporal power and riches are chiefly necessary; such punishment is granted chiefly to the secular power. The pope therefore, can, as a rule, correct wrongdoers only with a spiritual penalty. It is not, therefore, necessary that he should excel in temporal power or abound in temporal riches, but it is enough that Christians should willingly obey him."

"Numquam ponenda est pluralitas sine necessitate"

"Frustra fit per plura, quod potest fieri per pauciora."

"Intuitive cognition is such that when some things are cognized, of which one inheres in the other, or one is spatially distant from the other, or exists in some relation to the other, immediately in virtue of that non-propositional cognition of those things, it is known if the thing inheres or does not inhere, if it is spatially distant or not, and the same for other true contingent propositions, unless that cognition is flawed or there is some impediment."

"It is on account of theology alone that any assertion whatsoever should be called catholic or heretical. For only an assertion which is consonant with theology is truly catholic, and only one which is known to be opposed to theology is known to be heretical. For if some assertion were found to be opposed to decrees of the highest pontiffs, or also of general councils or also to laws of the emperors, nevertheless, if it were not in conflict with theology, even if it could be considered false, erroneous or unjust, it should not be counted as a heresy."

"The Holy Spirit through blessed John the evangelist makes a terrible threat against those who add anything to or take anything from divine scripture when he says in the last chapter of Revelations [22:18–9], "If any man shall add to these things, God shall add unto him the plagues which are in this book. And if any man shall take away from the words of the book of this prophecy, God shall take his part out of the book of life and out of the holy city, and from these things that are written in this book." We clearly gather from all these that nothing should be added to sacred scripture nor anything removed from it. To decide by way of teaching, therefore, which assertion should be considered catholic, which heretical, chiefly pertains to theologians, the experts on divine scripture. You see that I have set out opposing assertions in response to your question and I have touched on quite strong arguments in support of each position. Therefore consider now which seems the more probable to you."

"Purely philosophical assertions which do not pertain to theology should not be solemnly condemned or forbidden by anyone, because in connection with such [assertions] anyone at all ought to be free to say freely what pleases him."

"Entia non sunt multiplicanda praeter necessitatem."

"Mais apud me omnia fiunt Mathematicè in Natura"

"Le bon sens est la chose du monde la mieux partagée : car chacun pense en être si bien pourvu, que ceux même qui sont les plus difficiles à contenter en toute autre chose, n'ont point coutume d'en désirer plus qu'ils en ont."

"Je pense, donc je suis."

"I thought fit to... explain in detail in the same book the peculiarity of a certain method, by which it will be possible... to investigate some of the problems in mathematics by means of mechanics. This procedure is... no less useful even for the proof of the theorems themselves; for certain things first became clear to me by a mechanical method, although they had to be demonstrated by geometry afterwards... But it is of course easier, when we have previously acquired, by the method, some knowledge of the questions, to supply the proof than it is to find it without any previous knowledge."

"Historically, Ockham has been cast as the outstanding opponent of Thomas Aquinas (1224–1274): Aquinas perfected the great "medieval synthesis" of faith and reason and was canonized by the Catholic Church; Ockham destroyed the synthesis and was condemned by the Catholic Church. Although it is true that Aquinas and Ockham disagreed on most issues, Aquinas had many other critics, and Ockham did not criticize Aquinas any more than he did others. It is fair enough, however, to say that Ockham was a major force of change at the end of the Middle Ages. He was a courageous man with an uncommonly sharp mind. His philosophy was radical in his day and continues to provide insight into current philosophical debates. 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. In metaphysics, Ockham champions nominalism, the view that universal essences, such as humanity or whiteness, are nothing more than concepts in the mind. He develops an Aristotelian ontology, admitting only individual substances and qualities. In epistemology, Ockham defends direct realist empiricism, according to which human beings perceive objects through "intuitive cognition," without the help of any innate ideas. These perceptions give rise to all of our abstract concepts and provide knowledge of the world. In logic, Ockham presents a version of supposition theory to support his commitment to mental language. Supposition theory had various purposes in medieval logic, one of which was to explain how words bear meaning. Theologically, Ockham is a fideist, maintaining that belief in God is a matter of faith rather than knowledge. Against the mainstream, he insists that theology is not a science and rejects all the alleged proofs of the existence of God."

"From the middle of the Nineteenth Century, nearly every modern book on Logic has contained the words: Entia non sunt multiplicanda, præter necessitatem: quoted as if they were the words of William of Ockham. But nobody gives a particular reference to any work of the Singular and Invincible Doctor ... my own fruitless inquisition for the formula, in those works of Ockham which have been printed, has led me to disbelieve that he ever used it to express his Critique of Entities."

"In his controversial writings William of Ockham appears as the advocate of secular absolutism. He denies the right of the popes to exercise temporal power, or to interfere in any way whatever in the affairs of the Empire. ... In philosophy William advocated a reform of Scholasticism both in method and in content. The aim of this reformation movement in general was simplification. This aim he formulated in the celebrated "Law of Parsimony", commonly called "Ockham's Razor": "Entia non sunt multiplicanda sine necessitate". With this tendency towards simplification was united a very marked tendency towards skepticism a distrust, namely, of the ability of the human mind to reach certitude in the most important problems of philosophy. ... Ockham's attitude towards the established order in the Church and towards the recognized system of philosophy in the academic world of his day was one of protest. He has, indeed, been called "the first Protestant". Nevertheless, he recognized in his polemical writings the authority of the Church in spiritual matters, and did not diminish that authority in any respect. Similarly, although he rejected the rational demonstration of several truths which are fundamental in the Christian system of theology, he held firmly to the same truths as matters of faith."

"No doubt you know that Galileo had been convicted not long ago by the Inquisition, and that his opinion on the movement of the Earth had been condemned as heresy. Now I will tell you that all things I explain in my treatise, among which is also that same opinion about the movement of the Earth, all depend on one another, and are based upon certain evident truths. Nevertheless, I will not for the world stand up against the authority of the Church. ...I have the desire to live in peace and to continue on the road on which I have started."

"What I have given in the second book on the nature and properties of curved lines, and the method of examining them, is, it seems to me, as far beyond the treatment in the ordinary geometry, as the rhetoric of Cicero is beyond the a, b, c of children."

"M. Desargues puts me under obligations on account of the pains that it has pleased him to have in me, in that he shows that he is sorry that I do not wish to study more in geometry, but I have resolved to quit only abstract geometry, that is to say, the consideration of questions which serve only to exercise the mind, and this, in order to study another kind of geometry, which has for its object the explanation of the phenomena of nature... You know that all my physics is nothing else than geometry."

"Mr. Clerselier has written me that you are expecting from him my Meditations... in order to present them to the queen of the land. ...If I had only been as wise as they say the savages persuaded themselves that the monkeys were, I never would have become known as a maker of books: Since it is said that they imagined that the monkeys could indeed speak, if they wanted to, but that they chose not to so lest they be forced to work. And since I had not the same prudence to abstain from writing, I now have neither as much liesure nor as much peace as I would have had if I had kept quiet. But since the mistake has already been made, and since I am now known by an infinity of people at the academy, who look askance at my writings and scour them for means of harming me, I do have great hope of being known to persons of great merit, whose power and virtue could protect me."

"Me tenant comme je suis, un pied dans un pays et l'autre en un autre, je trouve ma condition très heureuse, en ce qu'elle est libre."