Immanuel Kant

"The concept of space, therefore, is a pure intuition, being a singular concept, not made up by sensations, but itself the fundamental form of all external sensation."

"The sensuous may be exceedingly distinct, while intellectual concepts are extremely confused. The former we observe in the prototype of sensuous knowledge geometry; the latter, in the organon of all intellectual concepts, metaphysics. It is evident how much toil the latter is expending to dispel the fogs of confusion darkening the common intellect, though not always with the happy success of the former science."

"The public use of a man's reason must be free at all times, and this alone can bring enlightenment among men..."

"If it were right to overstep a little the limits of apodictic certainty befitting metaphysics, it would seem worth while to trace out some things pertaining not merely to the laws but even to the causes of sensuous intuition, which are only intellectually knowable. Of course the human mind is not affected by external things, and the world does not lie open to its insight infinitely, except as far as itself together with all other things is sustained by the same infinite power of one. Hence it does not perceive external things but by the presence of the same common sustaining cause; and hence space, which is the universal and necessary condition of the joint presence of everything known sensuously, may be called the phenomenal omnipresence, for the cause of the universe is not present to all things and everything, as being in their places, but their places, that is the relations of the substances, are possible, because it is intimately present to all. Furthermore, since the possibility of the changes and successions of all things whose principle as far as sensuously known resides in the concept of time, supposes the continuous existence of the subject whose opposite states succeed; that whose states are in flux, lasting not, however, unless sustained by another; the concept of time as one infinite and immutable in which all things are and last, is the phenomenal eternity of the general cause} But it seems more cautious to hug the shore of the cognitions granted to us by the mediocrity of our intellect than to be carried out upon the high seas of such mystic investigations, like Malebranche, whose opinion that we see all things in God is pretty nearly what has here been expounded."

"Phenomena of the external sense are examined and set forth in physics; those of the internal sense in empirical psychology. Pure mathematics considers space in geometry and time in pure mechanics. To these is to be added a certain concept, intellectual to be sure in itself, but whose becoming actual in the concrete requires the auxiliary notions of time and space in the successive addition and simultaneous juxtaposition of separate units, which is the concept of number treated in arithmetic."

"It is difficult for the isolated individual to work himself out of the immaturity which has become almost natural for him. He has even become fond of it and for the time being is incapable of employing his own intelligence, because he has never been allowed to make the attempt. Statutes and formulas, these mechanical tools of a serviceable use, or rather misuse, of his natural faculties, are the ankle-chains of a continuous immaturity. Whoever threw it off would make an uncertain jump over the smallest trench because he is not accustomed to such free movement. Therefore there are only a few who have pursued a firm path and have succeeded in escaping from immaturity by their own cultivation of the mind."

"The guardians who have kindly undertaken the supervision will see to it that by far the largest part of mankind, including the entire "beautiful sex," should consider the step into maturity, not only as difficult but as very dangerous. After having made their domestic animals dumb and having carefully prevented these quiet creatures from daring to take any step beyond the lead-strings to which they have fastened them, these guardians then show them the danger which threatens them, should they attempt to walk alone."

"Nature, therefore, is subject with absolute precision to all the precepts of geometry as to all the properties of space there demonstrated, this being the subjective condition, not hypothetically but intuitively given, of every phenomenon in which nature can ever be revealed to the senses."

"Several actual worlds without one another are not, therefore, impossible by the very concept, as Wolf hastily concluded from the notion of a complex or multiplicity which he deemed sufficient to a whole, as such, but only on condition that there exist but one necessary cause of all things. If several are admitted, several worlds without one another will be possible in the strictest metaphysical sense."

"Morality is thus the relation of actions to the autonomy of the will, that is, to a possible giving of universal law through its maxims. An action that can coexist with the autonomy of the will is permitted; one that does not accord with it is forbidden. A will whose maxims necessarily harmonize with the laws of autonomy is a holy, absolutely good will. The dependence upon the principle of autonomy of a will that is not absolutely good (moral necessitation) is obligation. This, accordingly, cannot be attributed to a holy being. The objective of an action from obligation is called duty."

"Even if there never have been actions arising from such pure sources, what is at issue here is not whether this or that happened; that, instead, reason by itself and independently of all appearances commands what ought to happen; that, accordingly, actions of which the world has perhaps so far given no example, and whose very practicability might be very much doubted by one who bases everything on experience, are still inflexibly commanded by reason … because … duty … lies, prior to all experience, in the idea of a reason determing the will by means of apriori grounds."

"Through laziness and cowardice a large part of mankind, even after nature has freed them from alien guidance, gladly remain immature. It is because of laziness and cowardice that it is so easy for others to usurp the role of guardians. It is so comfortable to be a minor!"

"Freedom is the alone unoriginated birthright of man, and belongs to him by force of his humanity; and is independence on the will and co-action of every other in so far as this consists with every other person’s freedom."

"A spurious axiom of the first class is: Whatever is, is somewhere and sometime."

"A whole from necessary substances is impossible. The whole, therefore, of substances is a whole of contingent things, and the world consists essentially of only contingent things."

"The mind intent upon resolving as well as compounding the concept of a composite demands and presumes boundaries in which it may acquiesce in the former as well as in the latter direction."

"Let the letters a b c denote the three angular points of a rectilineal triangle. If the point did move continuously over the lines ab, bc, ca, that is, over the perimeter of the figure, it would be necessary for it to move at the point b in the direction ab, and also at the same point b in the direction bc. These motions being diverse, they cannot be simultaneous. There-fore, the moment of presence of the movable point at vertex b, considered as moving in the direction ab, is different from the moment of presence of the movable point at the same vertex b, considered as moving in the same direction bc. But between two moments there is time; therefore, the movable point is present at point b for some time, that is, it rests. Therefore it does not move continuously, which is contrary to the assumption. The same demonstration is valid for motion over any right lines including an assignable angle. Hence a body does not change its direction in continuous motion except by following a line no part of which is straight, that is, a curve, as Leibnitz maintained."

"Nature has willed that man should, by himself, produce everything that goes beyond the mechanical ordering of his animal existence, and that he should partake of no other happiness or perfection than that which he himself, independently of instinct, has created by his own reason."

"Reason in a creature is a faculty of widening the rules and purposes of the use of all its powers far beyond natural instinct; it acknowledges no limits to its projects. Reason itself does not work instinctively, but requires trial, practice, and instruction in order gradually to progress from one level of insight to another. Therefore a single man would have to live excessively long in order to learn to make full use of all his natural capacities. Since Nature has set only a short period for his life, she needs a perhaps unreckonable series of generations, each of which passes its own enlightenment to its successor in order finally to bring the seeds of enlightenment to that degree of development in our race which is completely suitable to Nature’s purpose. This point of time must be, at least as an ideal, the goal of man’s efforts, for otherwise his natural capacities would have to be counted as for the most part vain and aimless. This would destroy all practical principles, and Nature, whose wisdom must serve as the fundamental principle in judging all her other offspring, would thereby make man alone a contemptible plaything."

"The sham cause in physical influence consists in rashly assuming that the commerce of substance and transitive forces is sufficiently knowable from their mere existence. Hence it is not so much a system as rather the neglect of all philosophical system as a superfluity in the argument. Freeing the concept from this defect, we shall have a species of commerce alone deserving to be called real, and from which the whole constituting the world merits being called real, and not ideal or imaginary."

"Out of the crooked timber of humanity, no straight thing was ever made."

"The body is a temple."

"I freely admit that the remembrance of David Hume was the very thing that many years ago first interrupted my dogmatic slumber and gave a completely different direction to my researches in the field of speculative philosophy."

"It is absurd to excite reason against the primary postulates of pure time, as, for example, continuity, etc., since they follow from laws prior and superior to which nothing is found, and since reason herself in the use of the principle of contradiction cannot dispense with the support of this concept, so primitive and original is it."

"The wish to talk to God is absurd. We cannot talk to one we cannot comprehend — and we cannot comprehend God; we can only believe in Him. The uses of prayer are thus only subjective."

"Moral Teleology supplies the deficiency in physical Teleology, and first establishes a Theology; because the latter, if it did not borrow from the former without being observed, but were to proceed consistently, could only found a Demonology, which is incapable of any definite concept."

"Religion is too important a matter to its devotees to be a subject of ridicule. If they indulge in absurdities, they are to be pitied rather than ridiculed."

"The third of this kind of principles is : matter neither originates nor perishes; all the changes in the world concern form only ; a postulate which on the recommendation of common sense has spread through all philosophical schools, not because it is to be taken as having been found so, or as having been demonstrated by arguments a priori, but because if we were to admit that matter itself is fleeting and transitory, nothing at all that is stable and lasting would be left any longer to serve for the explication of phenomena according to universal and perpetual laws, and hence nothing at all would be left for the exercise of the intellect."

"I come now to another part of my system, and because it suggests a lofty idea of the plan of creation, it appears to me as the most seductive. The sequence of ideas that led us to it is very simple and natural. They are as follows: let us imagine a system of stars gathered together in a common plane, like those of the Milky Way, but situated so far away from us that even with the telescope we cannot distinguish the stars composing it; let us assume that its distance, compared to that separating us from the stars of the Milky Way, is the same proportion as the Milky Way is to the distance from the earth to the sun; such a stellar world will appear to the observer, who contemplates it at so enormous a distance, only as a little spot feebly illumined and subtending a very small angle; its shape will be circular, if its plane is perpendicular to the line of sight, elliptical, if it is seen obliquely. The faintness of its light, its form, and its appreciable diameter will obviously distinguish such a phenomenon from the isolated stars around it. We do not need to seek far in the observations of astronomers to meet with such phenomena. They have been seen by various observers, who have wondered at their strange appearance, have speculated about them, and have suggested some times the most amazing explanations, sometimes theories which were more rational, but which had no more foundation than the former. We refer to the nebulæ, or, more precisely, to a particular kind of celestial body which M. de Maupertius describes as follows: "These are small luminous patches, only slightly more brilliant than the dark background of the sky; they have this in common, that their shapes are more or less open elipses; and their light is far more feeble than that of any other objects to be perceived in the heavens." ...It is much more natural and reasonable to assume that a nebula is not a unique and solitary sun, but a system of numerous suns, which appear crowded, because of their distance, into a space so limited that their light, which would be imperceptible were each of them isolated, suffices, owing to their enormous numbers, to give a pale and uniform luster. Their analogy with our own system of stars; their form, which is precisely what it should be according to our theory; the faintness of their light, which denotes an infinite distance; all are in admirable accord and lead us to consider these elliptical spots as systems of the same order as our own—in a word, to be Milky Ways similar to the one whose constitution we have explained. And if these hypotheses, in which analogy and observation consistently lend mutual support, have the same merit as formal demonstrations, we must consider the existence of such systems as demonstrated... We see that scattered through space out to infinite distances, there exist similar systems of stars [nebulous stars, nebulæ], and that creation, in the whole extent of its infinite grandeur, is everywhere organized into systems whose members are in relation with one another.... A vast field lies open to discoveries, and observations alone will give the key."

"# Constitutional freedom, as the right of every citizen to have to obey no other law than that to which he has given his consent or approval;"

"The spurious axioms of the third kind from conditions proper to the subject whence they are transferred rashly to the object are plentiful, not, as in those of the Second Class, because the only way to the intellectual concept lies through the sensuous data, but because only by aid of the latter can the concept be applied to that which is given by experience, that is, can we know whether something is contained under a certain intellectual concept or not. To this class belongs the threadbare one of the schools: whatever exists contingently does at some time not exist. This spurious principle springs from the poverty of the intellect, having insight frequently into the nominal, rarely into the real, marks of contingency or necessity."

"The force of the word World, as commonly used, of itself falls in with us. For no one will attribute accidents to the World as parts, but as determinations, states; hence the so-called world of the ego, unrestrained by the single substance and its accidents, is not very appositely called a World, unless, perhaps, an imaginary one."

"Beneficence is a duty. He who often practices this, and sees his beneficent purpose succeed, comes at last really to love him whom he has benefited. When, therefore, it is said, "Thou shalt love thy neighbor as thyself," this does not mean, "Thou shalt first of all love, and by means of love (in the next place) do him good"; but: "Do good to thy neighbour, and this beneficence will produce in thee the love of men (as a settled habit of inclination to beneficence).""

"# Civil equality, as the right of the citizen to recognize no one as a superior among the people in relation to himself...; and"

"...happiness is not an ideal of reason but of imagination, resting solely on empirical grounds."

"Since the narrower or wider community of the peoples of the earth has developed so far that a violation of rights in one place is felt throughout the world, the idea of a cosmopolitan right is not fantastical, high-flown or exaggerated notion. It is a complement to the unwritten code of the civil and international law, necessary for the public rights of mankind in general and thus for the realization of perpetual peace."

"# Political independence, as the right to owe his existence and continuance in society not to the arbitrary will of another, but to his own rights and powers as a member of the commonwealth."

"By a lie a man throws away and, as it were, annihilates his dignity as a man. A man who himself does not believe what he tells another … has even less worth than if he were a mere thing. … makes himself a mere deceptive appearance of man, not man himself."

"Men will not understand … that when they fulfil their duties to men, they fulfil thereby God's commandments; that they are consequently always in the service of God, as long as their actions are moral, and that it is absolutely impossible to serve God otherwise."

"Space is employed as the type even of the concept of time itself, representing it by a line, and its limits — moments — by points. Time, on the other had, approaches more to a universal and rational concept, comprising under its relations all things whatsoever, to wit, space itself, and besides, those accidents which are not comprehended in the relations of space, such as the thoughts of the soul. Again, time, besides this, though it certainly does not dictate the laws of reason, yet constitutes the principal conditions tinder favor of which the mind compares its notions according to the laws of reason. Thus, I cannot judge what is impossible except by predicating a and not-a of the same subject at the same time."

"Have patience awhile; slanders are not long-lived. Truth is the child of time; erelong she shall appear to vindicate thee."

"Tibet... this is the highest country. No doubt it was inhabited before any other and could even have been the site of all creation and all science. The culture of the Indians, as is known is almost certainly came from Tibet, just as all our arts like agriculture, numbers, the game of chess, etc., seem to have come from India."

"As everybody likes to be honoured, so people imagine that God also wants to be honoured. They forget that the fulfilment of duty towards men is the only honour adequate to him. Thus is formed the conception of a religion of worship, instead of a merely moral religion. … Apart from moral conduct, all that man thinks himself able to do in order to become acceptable to God is mere superstition and religious folly. If once a man has come to the idea of a service which is not purely moral, but is supposed to be agreeable to God himself, or capable of propitiating him, there is little difference between the several ways of serving him. For all these ways are of equal value. … Whether the devotee accomplishes his statutory walk to the church, or whether he undertakes a pilgrimage to the sanctuaries of Loretto and Palestine, whether he repeats his prayer-formulas with his lips, or like the Tibetan, uses a prayer-wheel … is quite indifferent. As the illusion of thinking that a man can justify himself before God in any way by acts of worship is religious superstition, so the illusion that he can obtain this justification by the so-called intercourse with God is religious mysticism (Schwärmerei). Such superstition leads inevitably to sacerdotalism (Pfaffenthum) which will always be found where the essence is sought not in principles of morality, but in statutory commandments, rules of faith and observances."

"[Religion should be] .... successively freed from all statutes based on history, and one purely moral religion rule over all, in order that God might be all in all. The veil must fall. The leading-string of sacred tradition with all its appendices becomes by degrees useless, and at last a fetter … The humiliating difference between laymen and clergymen must disappear, and equality spring from true liberty. All this, however, must not be expected from an exterior revolution, which acts violently, and depends upon fortune In the principle of pure moral religion, which is a sort of divine revelation constantly taking place in the soul of man, must be sought the ground for a passage to the new order of things, which will be accomplished by slow and successive reforms."

"an intellectual concept abstracts from everything sensuous, it is not abstracted from sensuous things, and perhaps would be more correctly called abstracting than abstract. Intellectual concepts it is more cautious, therefore, to call pure ideas, and concepts given only empirically, abstract ideas."

"Es ist so bequem, unmündig zu sein. Habe ich ein Buch, das für mich Verstand hat, einen Seelsorger, der für mich Gewissen hat, einen Arzt, der für mich die Diät beurtheilt u. s. w., so brauche ich mich ja nicht selbst zu bemühen. Ich habe nicht nöthig zu denken, wenn ich nur bezahlen kann."

"The method of the science not being practiced much nowadays, except what logic prescribes to all sciences generally, that fitted for the peculiar nature of metaphysics being simply ignored, it is no wonder that those who everlastingly turn the Sisyphean stone of this inquiry do not seem so far to have made much progress. Though here I neither can nor will expatiate upon so important and extensive a subject, I shall briefly shadow forth what constitutes no despicable part of this method, namely, the infection between sensuous and intellectual cognition, not only as creeping in on those incautious in the application of principles, but even producing spurious principles under the appearance of axioms."

"Now the maximum of perfection is called ideal, by Plato, Idea — for instance, his Idea of a Republic — and is the principle of all that is contained under the general notion of any perfection, inasmuch as the lesser grades are not thought determinable but by limiting the maximum. But God, the Ideal of perfection, and hence the principle of cognition, is also, as existing really, the principle of the creation of all perfection."

"Percepts and phenomena which precedes the logical use of the intellect is called appearance, while the reflex knowledge originating from several appearances compared by the intellect is called experience."

"That all our knowledge begins with experience there can be no doubt. For how is it possible that the faculty of cognition should be awakened into exercise otherwise than by means of objects which affect our senses, and partly of them selves produce representations, partly rouse our powers of understanding into activity, to compare, to connect, or to separate these, and so to convert the raw material of our sensuous impressions into a knowledge of objects, which is called experience? In respect of time, therefore, no knowledge of ours is antecedent to experience, but begins with it. But though all our knowledge begins with experience, it by no means follows, that all arises out of experience. For, on the contrary, it is quite possible that our empirical knowledge is a compound of that which we receive through impressions, and that which the faculty of cognition supplies from itself (sensuous impressions giving merely the occasion)... It is, therefore, a question which requires close investigation, and is not to be answered at first sight,—whether there exists a knowledge altogether independent of experience, and even of all sensuous impressions? Knowledge of this kind is called à priori, in contradistinction to empirical knowledge which has its sources à posteriori, that is, in experience."