So act that your principle of action might safely be made a law for the whole world.

Immanuel Kant (22 April 172412 February 1804), born Emanuel Kant, was a German philosopher.


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.
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.
Men will not understand … that when they fulfil their duties to men, they fulfil thereby God's commandments...
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.
By a lie a man throws away and, as it were, annihilates his dignity as a man.
  • 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.
    • A lecture at Königsberg (1775), as quoted in A New Dictionary of Quotations on Historical Principles from Ancient and Modern Sources (1946) by H. L. Mencken, p. 955
  • 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.
    • A lecture at Königsberg (1775), as quoted in A New Dictionary of Quotations on Historical Principles from Ancient and Modern Sources (1946) by H. L. Mencken, p. 1017
  • The body is a temple.
    • A lecture at Königsberg (1775), as quoted in A New Dictionary of Quotations on Historical Principles from Ancient and Modern Sources (1946) by H. L. Mencken, p. 1043
  • Out of the crooked timber of humanity, no straight thing was ever made.
    • Idea for a General History with a Cosmopolitan Purpose (1784), Proposition 6.
    • Variant translations: Out of timber so crooked as that from which man is made nothing entirely straight can be built.
    • From such crooked wood as that which man is made of, nothing straight can be fashioned.
    • Never a straight thing was made from the crooked timber of man.
  • Happiness is not an ideal of reason but of imagination.
    • Fundamental Principles of the Metaphysics of Ethics (1785)
  • 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.
    • Perpetual Peace: A Philosophical Sketch (1795)
  • 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)."
    • Metaphysical Elements of Ethics (1780). Translated by Thomas Kingsmill Abbott, translation available at From section "Preliminary Notions of the Susceptibility of the Mind for Notions of Duty Generally", Part C ("Of love to men")
  • There are three juridical attributes that inseparably belong to the citizen by right. These are:
    1. 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;
    2. Civil equality, as the right of the citizen to recognize no one as a superior among the people in relation to himself...; and
    3. 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.
    • Science of Right (1797)
  • 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.
    • As quoted in German Thought, From The Seven Years' War To Goethe's Death : Six Lectures (1880) by Karl Hillebrand, p. 207
  • 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.
    • As quoted in German Thought, From The Seven Years' War To Goethe's Death : Six Lectures (1880) by Karl Hillebrand, p. 208
  • [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.
    • As quoted in German Thought, From The Seven Years' War To Goethe's Death : Six Lectures (1880) by Karl Hillebrand, p. 208
  • Have patience awhile; slanders are not long-lived. Truth is the child of time; erelong she shall appear to vindicate thee.
    • As quoted in Gems of Thought (1888) edited by Charles Northend
  • The death of dogma is the birth of morality.
    • As quoted in Faith Or Fact (1897) by Henry Moorehouse Taber, p. 86
  • 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.
    • Doctrine of Virtue as translated by Mary J. Gregor (1964), p. 93

An Original Theory or New Hypothesis of the Universe (1750)

  • 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.

Kant's Inaugural Dissertation (1770)

Kant's Inaugural Dissertation Of 1770 Translated Into English With An Introduction And Discussion By William J. Eckoef, Ph.D. Professor of Philosophy and Pedagogy in the University of Colorado May, 1894
  • De Mundi Sensibilis atque Intelligibilis Forma et Principiis
  • Dissertation on the Form and Principles of the Sensible and the Intelligible World

Section I On The Idea Of A World In General

  • As the analysis of a substantial composite terminates only in a part which is not a whole, that is, in a simple part, so synthesis terminates only in a whole which is not a part, that is, the world.
  • 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.
  • 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.

Section II On The Distinction Between The Sensible And The Intelligible Generally

  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

Section III On The Principles Of The Form Of The Sensible World

  • 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.
  • Those who assert the objective reality of time either conceive of it as a continuous flow in what exists, without, however, any existing thing, as is done especially by the English philosophers, an absurd fiction, or as something real abstracted from the succession of inner states, as it has been put by Leibnitz and his followers.
  • 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.
  • Of Space
  • The concept of space is not abstracted from external sensations.
  • 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.
  • 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.
  • Corollary
  • 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.

Section IV On The Principle Of The Form Of The Intelligible World

  • The question of the principle of the form of the intelligible world turns, therefore, upon making apparent in what manner it is possible for several substances to be in mutual commerce, and for this reason to pertain to the same whole, which is called world. We do not here consider the world, let it be understood, as to matter, that is, as to the nature of the substances of which it consists, whether they be material or immaterial, but as to form, that is to say, how among several things taken separately a connection, and among them all, totality can have place.
  • 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.
  • 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.
  • 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.
  • Scholium
  • 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.

Section V On The Method Respecting The Sensuous And The Intellectual In Metaphysics

  • The use of the intellect in the sciences whose primitive concepts as well as axioms are given by sensuous intuition is only logical, that is, by it we only subordinate cognitions to one another according to their relative universality conformably to the principle of contradiction, phenomena to more general phenomena, and consequences of pure intuition to intuitive axioms. But in pure philosophy, such as metaphysics, in which the use of the intellect in respect to principles is real, that is to say, where the primary concept of things and relations and the very axioms are given originally by the pure intellect itself, and not being intuitions do not enjoy immunity from error, the method precedes the whole science, and whatever is attempted before its precepts are thoroughly discussed and firmly established is looked upon as rashly conceived and to be rejected among vain instances of mental playfulness.
  • 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.
  • A spurious axiom of the first class is: Whatever is, is somewhere and sometime.
  • they cudgel their brains with absurd questions, such as, for instance, why God did not make the world many centuries earlier. They persuade themselves that it is easy to conceive, to be sure, how God may discern what is present, that is, what is actual in the time in which he is, but how He may foresee what is future, that is, what is actual in the time in which He is not yet, they deem an intellectual difficulty; as if the existence of the Necessary Being descended through all the moments of an imaginary time, and, having already exhausted a part of His duration, saw before Him the eternity He was yet to live simultaneously with the present events of the world. All these difficulties upon proper insight into the notion of time vanish like smoke.
  • The prejudices of the second species, since they impose upon the intellect by the sensual conditions restricting the mind if it wishes in certain cases to attain to what is intellectual, lurk more deeply. One of them is that which affects knowledge of quantity, the other that affecting knowledge of qualities generally. The former is: every actual multiplicity can be given numerically, and hence, every infinite quantity; the latter, whatever is impossible contradicts itself. In either of them the concept of time, it is true, does not enter into the very notion of the predicate, nor is it attributed as a qualification to the subject. But yet it serves as a means for forming an idea of the predicate, and thus, being a condition, affects the intellectual concept of the subject to the extent that the latter is only attained by its aid.
  • 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.
  • To these spurious principles must be added some others of great affinity with them… First, that by which we assume that everything in the universe is done according to the order of nature, which principle by Epicurus was proclaimed without any restriction, and by all other philosophers unanimously with extremely rare exceptions, not to be admitted but from supreme necessity.
  • The second is the partiality for unity proper to the philosophical mind, whence this wide-spread canon has flown forth: principles are not to be multiplied beyond supreme necessity, to which we give in our adhesion, not because we have insight into causal unity in the world either by reason or experience, but as seeking it by an impulse of the intellect which seems to itself to have by thus much advanced in the explication of phenomena, by as much as it is granted to it to descend from the same principle to a greater number of consequences,
  • 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.

Prolegomena to Any Future Metaphysics (1783)

  • 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.
    • Variant translation: I freely admit: it was David Hume's remark that first, many years ago, interrupted my dogmatic slumber and gave a completely different direction to my enquiries in the field of speculative philosophy.

What is Enlightenment? (1784)

translation by Lewis White Beck is available on Wikisource
There will always be some people who think for themselves, even among the self-appointed guardians of the great mass who, after having thrown off the yoke of immaturity themselves, will spread about them the spirit of a reasonable estimate of their own value and of the need for every man to think for himself.
  • Aufklärung ist der Ausgang des Menschen aus seiner selbst verschuldeten Unmündigkeit. Unmündigkeit ist das Unvermögen, sich seines Verstandes ohne Leitung eines anderen zu bedienen. Selbstverschuldet ist diese Unmündigkeit, wenn die Ursache derselben nicht am Mangel des Verstandes, sondern der Entschließung und des Mutes liegt, sich seiner ohne Leitung eines anderen zu bedienen. Sapere aude! Habe Mut dich deines eigenen Verstandes zu bedienen! ist also der Wahlspruch der Aufklärung.
    • Enlightenment is man’s leaving his self-caused immaturity. Immaturity is the incapacity to use one's intelligence without the guidance of another. Such immaturity is self-caused if it is not caused by lack of intelligence, but by lack of determination and courage to use one's intelligence without being guided by another. Sapere Aude! Have the courage to use your own intelligence! is therefore the motto of the enlightenment.
  • 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.
    • It is so easy to be immature. If I have a book to serve as my understanding, a pastor to serve as my conscience, a physician to determine my diet for me, and so on, I need not exert myself at all. I need not think, if only I can pay: others will readily undertake the irksome work for me.
  • 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!
  • 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.
  • 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.
  • There will always be some people who think for themselves, even among the self-appointed guardians of the great mass who, after having thrown off the yoke of immaturity themselves, will spread about them the spirit of a reasonable estimate of their own value and of the need for every man to think for himself.
  • A public can only arrive at enlightenment slowly. Through revolution, the abandonment of personal despotism may be engendered and the end of profit-seeking and domineering oppression may occur, but never a true reform of the state of mind. Instead, new prejudices, just like the old ones, will serve as the guiding reins of the great, unthinking mass.
    All that is required for this enlightenment is freedom; and particularly the least harmful of all that may be called freedom, namely, the freedom for man to make public use of his reason in all matters. But I hear people clamor on all sides: Don't argue! The officer says: Don't argue, drill! The tax collector: Don't argue, pay! The pastor: Don't argue, believe!
  • The public use of a man's reason must be free at all times, and this alone can bring enlightenment among men...

Idea for a Universal History from a Cosmopolitan Point of View (1784)

Idea for a Universal History from a Cosmopolitan Point of View (1784) as translated in ''On History (1963) by Lewis White Beck; also translated as Idea for a General History with a Cosmopolitan Purpose

  • Whatever concept one may hold, from a metaphysical point of view, concerning the freedom of the will, certainly its appearances, which are human actions, like every other natural event are determined by universal laws. However obscure their causes, history, which is concerned with narrating these appearances, permits us to hope that if we attend to the play of freedom of the human will in the large, we may be able to discern a regular movement in it, and that what seems complex and chaotic in the single individual may be seen from the standpoint of the human race as a whole to be a steady and progressive though slow evolution of its original endowment.
    • Introduction
  • Since men in their endeavors behave, on the whole, not just instinctively, like the brutes, nor yet like rational citizens of the world according to some agreed-on plan, no history of man conceived according to a plan seems to be possible, as it might be possible to have such a history of bees or beavers. One cannot suppress a certain indignation when one sees men’s actions on the great world-stage and finds, beside the wisdom that appears here and there among individuals, everything in the large woven together from folly, childish vanity, even from childish malice and destructiveness. In the end, one does not know what to think of the human race, so conceited in its gifts.
    • Introduction
  • All natural capacities of a creature are destined to evolve completely to their natural end.
    • First Thesis
    • Variant translations:
    • All natural capacities of a creature are destined sooner or later to be developed completely and in conformity with their end.
    • All natural capacities of a creature are destined to develop themselves completely and to their purpose.
  • In man (as the only rational creature on earth) those natural capacities which are directed to the use of his reason are to be fully developed only in the race, not in the individual.
    • Second Thesis
  • 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.
    • Second Thesis
    • Paraphrased variant: Reason does not work instinctively, but requires trial, practice, and instruction in order to gradually progress from one level of insight to another.
  • 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.
    • Third Thesis
  • Nature does nothing in vain, and in the use of means to her goals she is not prodigal. Her giving to man reason and the freedom of the will which depends upon it is clear indication of her purpose. Man accordingly was not to be guided by instinct, not nurtured and instructed with ready-made knowledge; rather, he should bring forth everything out of his own resources.
    • Third Thesis
  • The means employed by Nature to bring about the development of all the capacities of men is their antagonism in society, so far as this is, in the end, the cause of a lawful order among men.
    • Fourth Thesis
  • The greatest problem for the human race, to the solution of which Nature drives man, is the achievement of a universal civic society which administers law among men.
    • Fifth Thesis
  • This problem is the most difficult and the last to be solved by mankind.
    • Sixth Thesis
  • The master is himself an animal, and needs a master. Let him begin it as he will, it is not to be seen how he can procure a magistracy which can maintain public justice and which is itself just, whether it be a single person or a group of several elected persons. For each of them will always abuse his freedom if he has none above him to exercise force in accord with the laws. The highest master should be just in himself, and yet a man. This task is therefore the hardest of all; indeed, its complete solution is impossible, for from such crooked wood as man is made of, nothing perfectly straight can be built. That it is the last problem to be solved follows also from this: it requires that there be a correct conception of a possible constitution, great experience gained in many paths of life, and — far beyond these — a good will ready to accept such a constitution. Three such things are very hard, and if they are ever to be found together, it will be very late and after many vain attempts.
    • Sixth Thesis
    • Variant translations:
    • Out of the crooked timber of humanity, no straight thing was ever made.
    • Out of timber so crooked as that from which man is made nothing entirely straight can be built.
    • From such crooked wood as that which man is made of, nothing straight can be fashioned.
  • The problem of establishing a perfect civic constitution is dependent upon the problem of a lawful external relation among states and cannot be solved without a solution of the latter problem.
    • Seventh Thesis
  • What is the use of working toward a lawful civic constitution among individuals, i.e., toward the creation of a commonwealth? The same unsociability which drives man to this causes any single commonwealth to stand in unrestricted freedom in relation to others; consequently, each of them must expect from another precisely the evil which oppressed the individuals and forced them to enter into a lawful civic state. The friction among men, the inevitable antagonism, which is a mark of even the largest societies and political bodies, is used by Nature as a means to establish a condition of quiet and security. Through war, through the taxing and never-ending accumulation of armament, through the want which any state, even in peacetime, must suffer internally, Nature forces them to make at first inadequate and tentative attempts; finally, after devastations, revolutions, and even complete exhaustion, she brings them to that which reason could have told them at the beginning and with far less sad experience, to wit, to step from the lawless condition of savages into a league of nations. In a league of nations, even the smallest state could expect security and justice, not from its own power and by its own decrees, but only from this great league of nations … from a united power acting according to decisions reached under the laws of their united will.
    • Seventh Thesis
  • All wars are accordingly so many attempts (not in the intention of man, but in the intention of Nature) to establish new relations among states, and through the destruction or at least the dismemberment of all of them to create new political bodies, which, again, either internally or externally, cannot maintain themselves and which must thus suffer like revolutions; until finally, through the best possible civic constitution and common agreement and legislation in external affairs, a state is created which, like a civic commonwealth, can maintain itself automatically.
    • Seventh Thesis
  • Is it reasonable to assume a purposiveness in all the parts of nature and to deny it to the whole?
    • Seventh Thesis
  • To a high degree we are, through art and science, cultured. We are civilized — perhaps too much for our own good — in all sorts of social grace and decorum. But to consider ourselves as having reached morality — for that, much is lacking. The ideal of morality belongs to culture; its use for some simulacrum of morality in the love of honor and outward decorum constitutes mere civilization. So long as states waste their forces in vain and violent self-expansion, and thereby constantly thwart the slow efforts to improve the minds of their citizens by even withdrawing all support from them, nothing in the way of a moral order is to be expected. For such an end, a long internal working of each political body toward the education of its citizens is required. Everything good that is not based on a morally good disposition, however, is nothing but pretense and glittering misery. In such a condition the human species will no doubt remain until, in the way I have described, it works its way out of the chaotic conditions of its international relations.
    • Seventh Thesis
  • The history of mankind can be seen, in the large, as the realization of Nature’s secret plan to bring forth a perfectly constituted state as the only condition in which the capacities of mankind can be fully developed, and also bring forth that external relation among states which is perfectly adequate to this end.
    • Eighth Thesis
  • Everyone can see that philosophy can have her belief in a millennium, but her millennarianism is not Utopian, since the Idea can help, though only from afar, to bring the millennium to pass. The only question is: Does Nature reveal anything of a path to this end? And I say: She reveals something, but very little. This great revolution seems to require so long for its completion that the short period during which humanity has been following this course permits us to determine its path and the relation of the parts to the whole with as little certainty as we can determine, from all previous astronomical observation, the path of the sun and his host of satellites among the fixed stars. Yet, on the fundamental premise of the systematic structure of the cosmos and from the little that has been observed, we can confidently infer the reality of such a revolution.
    Moreover, human nature is so constituted that we cannot be indifferent to the most remote epoch our race may come to, if only we may expect it with certainty. Such indifference is even less possible for us, since it seems that our own intelligent action may hasten this happy time for our posterity. For that reason, even faint indications of approach to it are very important to us.
    • Eighth Thesis
  • A philosophical attempt to work out a universal history according to a natural plan directed to achieving the civic union of the human race must be regarded as possible and, indeed, as contributing to this end of Nature.
    • Ninth Thesis

Groundwork of the Metaphysics of Morals (1785)

German: Grundlegung zur Metaphysik der Sitten

  • A metaphysics of morals is therefore indispensably necessary, not merely because of a motive to speculation — for investigating the source of the practical basic principles that lie a priori in our reason — but also because morals themselves remain subject to all sorts of corruption as long as we are without that clue and supreme norm by which to appraise them correctly...
  • Ich soll niemals anders verfahren als so, dass ich auch wollen könne, meine Maxime solle ein allgemeines Gesetz werden.
    • I ought never to act except in such a way that I could also will that my maxim should become a universal law.
      • Kant's supreme moral principle or "categorical imperative"; Variant translations:
        Act only on that maxim which you can at the same time will that it should become a universal law.
        Act as if the maxim of thy action were to become by thy will a universal law of nature.
        So act that your principle of action might safely be made a law for the whole world.
        May you live your life as if the maxim of your actions were to become universal law.
        Live your life as though your every act were to become a universal law.
        Do not feel forced to act, as you're only willing to act according to your own universal laws. And that's good. For only willfull acts are universal. And that's your maxim.
  • I do not, therefore, need any penetrating acuteness to see what I have to do in order that my volition be morally good. Inexperienced in the course of the world, incapable of being prepared for whatever might come to pass in it, I ask myself only: can you also will that your maxim become a universal law?
  • 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.
  • 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.
  • Im Reiche der Zwecke hat alles entweder einen Preis oder eine Würde. Was einen Preis hat, an dessen Stelle kann auch etwas anderes als Äquivalent gesetzt werden; was dagegen über allen Preis erhaben ist, mithin kein Äquivalent verstattet, das hat eine Würde.
    • In the kingdom of ends everything has either a price or a dignity. What has a price can be replaced by something else as its equivalent; what on the other hand is raised above all price and therefore admits of no equivalent has a dignity.
      • 434:32, M. Gregor, trans. (Cambridge: 1998), p. 42
  • Die menschliche Vernunft hat hier, wie allerwärts in ihrem reinen Gebrauche, so lange es ihr an Kritik fehlt, vorher alle mögliche unrechte Wege versucht, ehe es ihr gelingt, den einzigen wahren zu treffen.
    • Here as elsewhere human reason in its pure use, so long as it was not critically examined, has first tried all possible wrong ways before it succeeded in finding the one true way.

Metaphysical Foundations of Natural Science (1786)

  • I maintain that in every special natural doctrine only so much science proper is to be met with as mathematics; for... science proper, especially of nature, requires a pure portion, lying at the foundation of the empirical, and based upon à priori knowledge of natural things. ...the conception should be constructed. But the cognition of the reason through construction of conceptions is mathematical. A pure philosophy of nature in general, namely, one that only investigates what constitutes a nature in general, may thus be possible without mathematics; but a pure doctrine of nature respecting determinate natural things (corporeal doctrine and mental doctrine), is only possible by means of mathematics; and as in every natural doctrine only so much science proper is to be met with therein as there is cognition à priori, a doctrine of nature can only contain so much science proper as there is in it of applied mathematics.
  • All natural philosophers, who wished to proceed mathematically in their work, have hence invariably (although unknown to themselves) made use of metaphysical principles, and must make use of such, it matters not how energetically they may otherwise repudiate any claim of metaphysics on their science.
    • Preface, Tr. Bax (1883)
  • All true metaphysics is taken from the essential nature of the thinking faculty itself, and therefore in nowise invented, since it is not borrowed from experience, but contains the pure operations of thought, that is, conceptions and principles à priori, which the manifold of empirical presentations first of all brings into legitimate connection, by which it can become empirical knowledge, i.e. experience. ...mathematical physicists were thus quite unable to dispense with such metaphysical principles...
    • Preface, Tr. Bax (1883)
  • Natural science is throughout either a pure or an applied doctrine of motion.
    • Preface, Tr. Bax (1883)
  • I have in this treatise followed the mathematical method, if not with all strictness, at least imitatively, not in order, by a display of profundity, to procure a better reception for it, but because I believe such a system to be quite capable of it, and that perfection may in time be obtained by a cleverer hand, if stimulated by this sketch, mathematical investigators of nature should find it not unimportant to treat the metaphysical portion, which anyway cannot be got rid of, as a special fundamental department of general physics, and to bring it into unison with the mathematical doctrine of motion.
    • Preface, Tr. Bax (1883)
  • Newton... (after having remarked that geometry only requires two of the mechanical actions which it postulates, namely, to describe a straight line and a circle) says: geometry is proud of being able to achieve so much while taking so little from extraneous sources. One might say of metaphysics, on the other hand: it stands astonished, that with so much offered it by pure mathematics it can effect so little. In the meantime, this little is something which mathematics indispensably requires in its application to natural science, which, inasmuch as it must here necessarily borrow from metaphysics, need not be ashamed to allow itself to be seen in company with the latter.
    • Preface, Tr. Bax (1883) citing Isaac Newton's Principia

Critique of Pure Reason (1781; 1787)

  • Human reason has this peculiar fate that in one species of its knowledge it is burdened by questions which, as prescribed by the very nature of reason itself, it is not able to ignore, but which, as transcending all its powers, it is also not able to answer.
    • Preface, A vii
  • Mathematics, from the earliest times to which the history of human reason can reach, has followed, among that wonderful people of the Greeks, the safe way of science. But it must not be supposed that it was as easy for mathematics as for logic, in which reason is concerned with itself alone, to find, or rather to make for itself that royal road. I believe, on the contrary, that there was a long period of tentative work (chiefly still among the Egyptians), and that the change is to be ascribed to a revolution, produced by the happy thought of a single man, whose experiments pointed unmistakably to the path that had to be followed, and opened and traced out for the most distant times the safe way of a science. The history of that intellectual revolution, which was far more important than the passage round the celebrated Cape of Good Hope, and the name of its fortunate author, have not been preserved to us. ... A new light flashed on the first man who demonstrated the properties of the isosceles triangle (whether his name was Thales or any other name), for he found that he had not to investigate what he saw hi the figure, or the mere concepts of that figure, and thus to learn its properties; but that he had to produce (by construction) what he had himself, according to concepts a priori, placed into that figure and represented in it, so that, in order to know anything with certainty a priori, he must not attribute to that figure anything beyond what necessarily follows from what he has himself placed into it, in accordance with the concept.
  • Abbot Terrasson tells us that if the size of a book were measured not by the number of its pages but by the time required to understand it, then we could say about many books that they would be much shorter were they not so short.
    • A xix
  • 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.
    • Preface to 2nd edition, Tr. F. Max Müller (1905)
  • I have therefore found it necessary to deny knowledge in order to make room for faith.
Ich musste das Wissen aufheben, um zum Glauben Platz zu bekommen.
  • Preface to 2nd edition, B xxx
  • Criticism alone can sever the root of materialism, fatalism, atheism, free-thinking, fanaticism, and superstition, which can be injurious universally; as well as of idealism and skepticism, which are dangerous chiefly to the Schools, and hardly allow of being handed on to the public.
    • B xxxiv
  • The light dove, cleaving the air in her free flight, and feeling its resistance, might imagine that its flight would be still easier in empty space.
    • B 8
  • All thought must, directly or indirectly, by way of certain characters, relate ultimately to intuitions, and therefore, with us, to sensibility, because in no other way can an object be given to us.
    • B 33
  • Thoughts without content are empty, intuitions without concepts are blind. The understanding can intuit nothing, the senses can think nothing. Only through their unison can knowledge arise.
    • A 51, B 75
  • Psychologists have hitherto failed to realize that imagination is a necessary ingredient of perception itself.
    • A 120
  • All our knowledge falls with the bounds of experience.
    • A 146, B 185
  • It is therefore correct to say that the senses do not err — not because they always judge rightly, but because they do not judge at all.
    • A 293, B 350
  • This proof can at most, therefore, demonstrate the existence of an architect of the world, whose efforts are limited by the capabilities of the material with which he works, but not of a creator of the world, to whom all things are subject.
    • A 627, B 655 (Physico-Theological Proof Impossible)
  • Philosophical knowledge is the knowledge gained by reason from concepts; mathematical knowledge is the knowledge gained by reason from the construction of concepts.
    • A 713, B 741
  • It is precisely in knowing its limits that philosophy consists.
    • A 727, B 755
  • I have no knowledge of myself as I am, but merely as I appear to myself.
    • B 158
  • A plant, an animal, the regular order of nature — probably also the disposition of the whole universe — give manifest evidence that they are possible only by means of and according to ideas; that, indeed, no one creature, under the individual conditions of its existence, perfectly harmonizes with the idea of the most perfect of its kind — just as little as man with the idea of humanity, which nevertheless he bears in his soul as the archetypal standard of his actions; that, notwithstanding, these ideas are in the highest sense individually, unchangeably, and completely determined, and are the original causes of things; and that the totality of connected objects in the universe is alone fully adequate to that idea.
    • B 374
  • Metaphysics has as the proper object of its enquiries three ideas only: God, freedom, and immortality.
    • B 395
  • All human knowledge begins with intuitions, proceeds from thence to concepts, and ends with ideas.
    • B 730; Variant translation: All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.
  • For it is extremely absurd to expect to be enlightened by reason, and yet to prescribe to her beforehand on which side she must incline.
    • A 747, B 775; as translated by F. Max Mueller
  • All the interests of my reason, speculative as well as practical, combine in the three following questions: 1. What can I know? 2. What ought I to do? 3. What may I hope?
    • B 832-833
  • 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.
    • Introduction I. Of the Difference Between Pure and Empirical Knowledge

Critique of Practical Reason (1788)

Two things fill the mind with ever-increasing wonder and awe, the more often and the more intensely the mind of thought is drawn to them: the starry heavens above me and the moral law within me.
Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.
  • The inscrutable wisdom through which we exist is not less worthy of veneration in respect to what it denies us than in respect to what it has granted.
  • Two things fill the mind with ever-increasing wonder and awe, the more often and the more intensely the mind of thought is drawn to them: the starry heavens above me and the moral law within me.
    • Variant translations:
      • Two things fill the mind with ever new and increasing admiration and awe, the oftener and more steadily we reflect on them: the starry heavens above me and the moral law within me.
        • Translated by Lewis White Beck
      • Two things fill the heart with renewed and increasing awe and reverence the more often and the more steadily that they are meditated on: the starry skies above me and the moral law inside me.
  • Two things fill the mind with ever new and increasing admiration and awe, the oftener and the more steadily we reflect on them: the starry heavens above and the moral law within. I have not to search for them and conjecture them as though they were veiled in darkness or were in the transcendent region beyond my horizon; I see them before me and connect them directly with the consciousness of my existence. The former begins from the place I occupy in the external world of sense, and enlarges my connection therein to an unbounded extent with worlds upon worlds and systems of systems, and moreover into limitless times of their periodic motion, its beginning and continuance. The second begins from my invisible self, my personality, and exhibits me in a world which has true infinity, but which is traceable only by the understanding, and with which I discern that I am not in a merely contingent but in a universal and necessary connection, as I am also thereby with all those visible worlds. The former view of a countless multitude of worlds annihilates as it were my importance as an animal creature, which after it has been for a short time provided with vital power, one knows not how, must again give back the matter of which it was formed to the planet it inhabits (a mere speck in the universe). The second, on the contrary, infinitely elevates my worth as an intelligence by my personality, in which the moral law reveals to me a life independent of animality and even of the whole sensible world, at least so far as may be inferred from the destination assigned to my existence by this law, a destination not restricted to conditions and limits of this life, but reaching into the infinite.
    • Translated by Thomas Kingsmill Abbott
  • Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.

Critique of Judgment (1790)

  • it is absurd … to hope that maybe another Newton may some day arise, to make intelligible to us even the genesis of but a blade of grass ("Dialectic of Teleological Judgment" §75)

Religion within the Limits of Reason Alone (1793)

Full text in German
Full Text in English 1838 translation
  • That religion in which I must know in advance that something is a divine command in order to recognize it as my duty, is the revealed religion (or the one standing in need of a revelation); in contrast, that religion in which I must first know that something is my duty before I can accept it as a divine injunction is the natural religion. … When religion is classified not with reference to its first origin and its inner possibility (here it is divided into natural and revealed religion) but with respect to its characteristics which make it capable of being shared widely with others, it can be of two kinds: either the natural religion, of which (once it has arisen) everyone can be convinced through his own reason, or a learned religion, of which one can convince others only through the agency of learning (in and through which they must be guided). … A religion, accordingly, can be natural, and at the same time revealed, when it is so constituted that men could and ought to have discovered it of themselves merely through the use of their reason, although they would not have come upon it so early, or over so wide an area, as is required. Hence a revelation thereof at a given time and in a given place might well be wise and very advantageous to the human race, in that, when once the religion thus introduced is here, and has been made known publicly, everyone can henceforth by himself and with his own reason convince himself of its truth. In this event the religion is objectively a natural religion, though subjectively one that has been revealed.
    • Book IV, Part 1
  • There is needed, no doubt, a body of servants (ministerium) of the invisible church, but not officials (officiales), in other words, teachers but not dignitaries, because in the rational religion of every individual there does not yet exist a church as a universal union (omnitudo collectiva).
    • Book IV, Part 1, Section 1, “The Christian religion as a natural religion”
  • Let us suppose there was a teacher of whom an historical record (or, at least, a widespread belief which is not basically disputable) reports that he was the first to expound publicly a pure and searching religion, comprehensible to the whole world. … Suppose that all he did was done even in the face of a dominant ecclesiastical faith which was onerous and not conducive to moral ends (a faith whose perfunctory worship can serve as a type of all the other faiths, at bottom merely statutory, which were current in the world at the time). Suppose, further, we find that he had made this universal religion of reason the highest and indispensable condition of every religious faith whatsoever … and this without further adding to this faith burdensome new ordinances or wishing to transform acts which he had initiated into peculiar holy practices, required in themselves as being constituent elements of religion. After this description one will not fail to recognize the person who can be referenced, not indeed as the founder of the religion which, free from every dogma, is engraved in all men’s hearts (for it does not have its origin in an arbitrary will), but as the founder of the first true church.
    • Book IV, Part 1, Section 1, “The Christian religion as a natural religion”
  • He [Jesus] claims that not the observance of outer civil or statutory churchly duties but the pure moral disposition of the heart alone can make man well-pleasing to God (Matthew V, 20-48); … that injury done one’s neighbor can be repaired only through satisfaction rendered to the neighbor himself, not through acts of divine worship (V, 24). Thus, he says, does he intend to do full justice to the Jewish law (V, 17); whence it is obvious that not scriptural scholarship but the pure religion of reason must be the law’s interpreter, for taken according to the letter, it allowed the very opposite of all this. Furthermore, he does not leave unnoticed, in his designations of the strait gate and the narrow way, the misconstruction of the law which men allow themselves in order to evade their true moral duty, holding themselves immune through having fulfilled their churchly duty (VII, 13). He further requires of these pure dispositions that they manifest themselves also in works (VII, 16) and, on the other hand, denies the insidious hope of those who imagine that, through invocation and praise of the Supreme Lawgiver in the person of His envoy, they will make up for their lack of good works and ingratiate themselves into favor (VII, 21). Regarding these works he declares that they ought to be performed publicly, as an example for imitation (V, 16), and in a cheerful mood, not as actions extorted from slaves (VI, 16); and that thus, from a small beginning in the sharing and spreading of such dispositions, religion, like a grain of seed in good soil, or a ferment of goodness, would gradually, through its inner power, grow into a kingdom of God (XIII, 31-33).
    • Book IV, Part 1, Section 1, “The Christian religion as a natural religion”
  • He [Jesus] combines all duties (1) in one universal rule (which includes within itself both the inner and the outer moral relations of men), namely: Perform your duty for no motive other than unconditioned esteem for duty itself, i.e., love God (the Legislator of all duties) above all else; and (2) in a particular rule, that, namely, which concerns man’s external relation to other men as universal duty: Love every one as yourself, i.e., further his welfare from good-will that is immediate and not derived from motives of self-advantage. These commands are not mere laws of virtue but precepts of holiness which we ought to pursue, and the very pursuit of them is called virtue. Accordingly he destroys the hope of all who intend to wait upon this moral goodness quite passively, with their hands in their laps, as though it were a heavenly gift which descends from on high. He who leaves unused the natural predisposition to goodness which lies in human nature (like a talent entrusted to him) in lazy confidence that a higher moral influence will no doubt supply the moral character and completeness which he lacks, is confronted with the threat that even the good which, by virtue of his natural predisposition, he may have done, will not be allowed to stand him in stead because of this neglect (XXV, 29).
    • Book IV, Part 1, Section 1, “The Christian religion as a natural religion”
  • When the man governed by self-interest, the god of this world, does not renounce it but merely refines it by the use of reason and extends it beyond the constricting boundary of the present, he is represented (Luke XVI, 3-9) as one who, in his very person [as servant], defrauds his master [self- interest] and wins from him sacrifices in behalf of “duty.”
    • Book IV, Part 1, Section 2, “The Christian religion as a natural religion”
  • Christianity possesses the great advantage over Judaism of being represented as coming from the mouth of the first Teacher not as a statutory but as a moral religion, and as thus entering into the closest relation with reason so that, through reason, it was able of itself, without historical learning, to be spread at all times and among all peoples with the greatest trustworthiness.
    • Book IV, Part 1, Section 1, “The Christian religion as a learned religion”
  • Alles, was ausser dem guten Lebenswandel der Mensch noch thun zu können vermeint, um Gott wohlgefällig zu werden, ist blosser Religionswahn und Afterdienst Gottes.
    • Whatever, over and above good life-conduct, man fancies that he can do to become well-pleasing to God is mere religious delusion.
      • Book IV, Part 2, Section 2
  • Die Verehrung mächtiger unsichtbarer Wesen, welche dem hülflosen Menschen durch die natürliche, auf dem Bewusstsein seines Unvermögens gegründete Furcht abgenöthigt wurde, …
    • The veneration of mighty invisible beings, which was extorted from helpless man through natural fear rooted in the sense of his impotence …
      • Book IV, Part 2, Section 3
  • Von einem tungusischen Schaman, bis zu dem Kirche und Staat zugleich regierenden europäischen Prälaten … ist zwar ein mächtiger Abstand in der Manier, aber nicht im Prinzip, zu glauben; denn was dieses betrifft, so gehören sie insgesammt zu einer und derselben Klasse, derer nämlich, die in dem, was an sich keinen bessern Menschen ausmacht (im Glauben gewisser statutarischer Sätze, oder Begehen gewisser willkürlicher Observanzen), ihren Gottesdienst setzen. Diejenigen allein, die ihn lediglich in der Gesinnung eines guten Lebenswandels zu finden gemeint sind, unterscheiden sich von jenen durch den Ueberschritt zu einem ganz andern und über das erste weit erhabenen Prinzip.
    • We can indeed recognize a tremendous difference in manner, but not in principle, between a shaman of the Tunguses and a European prelate: … for, as regards principle, they both belong to one and the same class, namely, the class of those who let their worship of God consist in what in itself can never make man better (in faith in certain statutory dogmas or celebration of certain arbitrary observances). Only those who mean to find the service of God solely in the disposition to good life-conduct distinguish themselves from those others, by virtue of having passed over to a wholly different principle.
      • Book IV, Part 2, Section 3
  • The question here is not, “How conscience ought to be guided? For Conscience is its own General and Leader; it is therefore enough that each man have one. What we want to know is, how conscience can be her own Ariadne, and disentangle herself from the mazes even of the most raveled and complicated casuistical theology. Here is an ethical proposition that stands in need of no proof: No Action May At Any Time Be Hazarded On The Uncertainty That Perchance It May Not Be Wrong (Quod dubitas, ne feceris! Pliny - which you doubt, then neither do) Hence the Consciousness, that Any Action I am about to perform is Right, is in itself a most immediate and imperative duty. What actions are right, - what wrong – is a matter for the understanding, not for conscience. p. 251
    • Book IV, Part 2, Section 4
  • Although individuals who have begun to awake to freedom of cogitation, after having long unconsciously slumbered under the yoke of a belief (e.g. Protestants), do straightway deem themselves ennobled, in proportion to their articles of belief are scanty; yet, singularly enough, they whose understandings still lie dormant, cling to a very different principle of safety. “Better Believe Too Much Than Believe Too Little,” is here the adage; for whatever is done beyond and above what is duty, cannot in any event harm, but may perchance to good. Upon this delusive dream, which would make dishonesty the very spirit and soul of religious confession, is based on the well-known argumentum a tuto, which obtains a more easy and extended currency, because religion compensates for every fault, and hence also for dishonesty in adopting it. If, says the sciolist, what I profess to believe concerning the Godhead is correct, then I have precisely hit the very truth. Should, on the other hand, the articles contain an error, still, as there is nothing in them morally improper, then have I merely assented to something superfluous and unnecessary, by all which I have no doubt molested, but certainly not incriminated myself. The peril arising out of the improbity of his profession – The Lesson of Conscience-necessarily undergone, when what is declared in the presence of God to be certain, which mankind must nevertheless know not to be so constituted as to admit of being affirmed with unconditioned certainty, are all overlooked by this dishonest maxim, And Indeed Pass With The Hypocrite For Nothing. The genuine safety-principle of true religion is contrariwise as follows. Whatever is a mean or condition of future bliss, unknown to naked reason, and promulgated singly by revelation, can strike root in my conviction, just like any other history; and so far forth as it does not militate against morality, cannot be absolutely false. Besides leaving this point totally undecided, I may unquestionably trust, that whatever of salutary there may lie in a document, will stand me in good stead, provided I do not by my moral short-coming make myself unworthy of it. In this maxim, there is a real moral safety, viz. That conscience be not violated; and more cannot be demanded from mankind. There is, moreover, an utmost danger and insecurity in that lauded stratagem of expediency, whereby we think astutely to evade any disadvantageous sequents that may spring from unbelieving nonconformity. Thus tampering with either party, we destroy our credit with both.
    • Book IV, Part 2, Section 4
    • Immanuel Kant, Religion Within the Boundary of Pure Reason 1793 translated by James W Semple, Advocate ,Edinburgh 1838 p. 255-257

Eternal Peace (1795)

Eternal Peace : And Other International Essays (1914), as translated by William Hastie
  • The universal and lasting establishment of peace constitutes not merely a part, but the whole final purpose and end of the science of right as viewed within the limits of reason.
  • …sogar daß ihm auch wohl Philosophen, als einer gewissen Veredelung der Menschheit, eine Lobrede halten, uneingedenk des Ausspruchs jenes Griechen: »Der Krieg ist darin schlimm, daß er mehr böse Leute macht, als er deren wegnimmt«.
    • Even philosophers will praise war as ennobling mankind, forgetting the Greek who said: War is bad in that it begets more evil than it kills.
      • As quoted in Philosophical Perspectives on Peace: An Anthology of Classical and Modern Sources (1987) by Howard P. Kainz, p. 81

Metaphysics of Morals (1797)

Die Metaphysik der Sitten (1797) Translated as Introduction to the Metaphysics of Morals and aslo in two parts as The Metaphysical Principles of Right and Metaphysical Principles of Virtue
  • Even if a civil society were to be dissolved by the consent of all its members (e.g., if a people inhabiting an island decided to separate and disperse throughout the world), the last murderer remaining in prison would first have to be executed, so that each has done to him what his deeds deserve and blood guilt does not cling to the people for not having insisted upon this punishment; for otherwise the people can be regarded as collaborators in his public violation of justice.
    • Kt6:333
  • Der kategorische Imperativ, der überhaupt nur aussagt, was Verbindlichkeit sei, ist: handle nach einer Maxime, welche zugleich als ein allgemeines Gesetz gelten kann.
    • There is … only a single categorical imperative and it is this: Act only on that maxim through which you can at the same time will that it should become a universal law.
      • Ch. 11
  • Human freedom is realised in the adoption of humanity as an end in itself, for the one thing that no-one can be compelled to do by another is to adopt a particular end.
    • Part Two : Metaphysical Principles of Virtue
  • Only the descent into the hell of self-knowledge can pave the way to godliness.
    • [N]ur die Höllenfahrt des Selbsterkenntnisses bahnt den Weg zur Vergötterung ...
    • Ak 6:441

On a Supposed Right to Tell Lies from Benevolent Motives (1797)

  • For instance, if you have by a lie hindered a man who is even now planning a murder, you are legally responsible for all the consequences. But if you have strictly adhered to the truth, public justice can find no fault with you, be the unforeseen consequence what it may. It is possible that whilst you have honestly answered Yes to the murderer’s question, whether his intended victim is in the house, the latter may have gone out unobserved, and so not have come in the way of the murderer, and the deed therefore have not been done; whereas, if you lied and said he was not in the house, and he had really gone out (though unknown to you) so that the murderer met him as he went, and executed his purpose on him, then you might with justice be accused as the cause of his death. For, if you had spoken the truth as well as you knew it, perhaps the murderer while seeking for his enemy in the house might have been caught by neighbours coming up and the deed been prevented.

Anthropology from a Pragmatic Point of View (1798)

Book deriving from lectures he delivered annually between 1772/73 and 1795/96, see Anthropology from a Pragmatic Point of View and Introduction to Kant's Anthropology (by Michel Foucault)
  • The Palestinians living among us have, for the most part, earned a not unfounded reputation for being cheaters, because of their spirit of usury since their exile. Certainly, it seems strange to conceive of a nation of cheaters; but it is just as odd to think of a nation of merchants, the great majority of whom, bound by an ancient superstition that is recognized by the State they live in, seek no civil dignity and try to make up for this loss by the advantage of duping the people among whom they find refuge, and even one another. The situation could not be otherwise, given a whole nation of merchants, as non-productive members of society (for example, the Jews in Poland).
  • What vexations there are in the external customs which are thought to belong to religion, but which in reality are related to ecclesiastical form! The merits of piety have been set up in such away that the ritual is of no use at all except for the simple submission of the believers to ceremonies and observances, expiations and mortifications (the more the better). But such compulsory services, which are mechanically easy (because no vicious inclination is thus sacrificed), must be found morally very difficult and burdensome to the rational man. When, therefore, the great moral teacher said, 'My commandments are not difficult,' he did not mean that they require only limited exercise of strength in order to be fulfilled. As a matter of fact, as commandments which require pure dispositions of the heart, they are the hardest that can be given. Yet, for a rational man, they are nevertheless infinitely easier to keep than the commandments involving activity which accomplishes nothing... [since] the mechanically easy feels like lifting hundredweights to the rational man when he sees that all the energy spent is wasted.
  • Habit... makes the endurance of evil easy (which, under the name of patience, is falsely honored as a virtue), because sensations of the same type, when continued without alteration for a long time, draw our attention away from the senses so that we are scarcely conscious of them at all. On the other hand, habit also makes the consciousness and the remembrance of good that has been received more difficult, which then gradually leads to ingratitude (a real vice). [...] Acquired habit deprives good actions of their moral value because it undermines mental freedom and, moreover, it leads to thoughtless repetitions of the same acts (monotony), and thus becomes ridiculous.
    • Kant, Immanuel (1996), pages 34-35
  • Collectively, the more civilized men are, the more they are actors. They assume the appearance of attachment, of esteem for others, of modesty, and of disinterestedness, without ever deceiving anyone, because everyone understands that nothing sincere is meant. Persons are familiar with this, and it is even a good thing that this is so in this world, for when men play these roles, virtues are gradually established, whose appearance had up until now only been affected. These virtues ultimately will become part of the actor's disposition. To deceive the deceiver in ourselves, or the tendency to deceive, is a fresh return to obedience[.]
    • Kant, Immanuel (1996), page 37
  • Young man! Deny yourself satisfaction (of amusement, of debauchery, of love, etc.), not with the Stoical intention of complete abstinence, but with the refined Epicurean intention of having in view an ever-growing pleasure. This stinginess with the cash of your vital urge makes you definitely richer through the postponement of pleasure, even if you should, for the most part, renounce the indulgence of it until the end of your life. The awareness of having pleasure under your control is, like everything idealistic, more fruitful and more abundant than everything that satisfies the sense through indulgence because it is thereby simultaneously consumed and consequently lost from the aggregate of totality.
    • Kant, Immanuel (1996), page 54.
  • [T]o require that a so-called layman should not use his own reason in religious matters, particularly since religion is to be appreciated as moral, but instead follow the appointed clergyman and thus someone else's reason, is an unjust demand because as to morals every man must account for all his doings. The clergyman will not and even cannot assume such a responsibility.
    • Kant, Immanuel (1996), pages 94-95
  • The guidelines for achieving wisdom consist of three leading maxims: 1) Think for yourself; 2) (in communication with other people) Put yourself in the place of the other person; 3) Always think by remaining faithful to your own self.
    • Kant, Immanuel (1996), page 95
  • A mind of slow apprehension is therefore not necessarily a weak mind. The one who is alert with abstractions is not always profound, he is more often very superficial.
    • Kant, Immanuel (1996), page 99
  • Through failures one becomes intelligent; but the one who has trained himself in this subject so that he can make others wise through their own failures, has used his intelligence. Ignorance is not stupidity.
    • Kant, Immanuel (1996), page 100
  • The deceiver is really the fool.
    • Kant, Immanuel (1996), page 101
  • [W]hat alone has value is the use to which life is put and the end to which it is directed. The value of life has to be created by man, it cannot be obtained through luck but only through wisdom. He who is anxiously concerned over losing his life will never enjoy life.
    • Kant, Immanuel (1996), pages 141
  • Money is the password, and all doors, which are closed to the man of lesser means, fly open to those whom Plutus favors. The invention of money, which has no other usefulness (or at least it should not have any) except for the commercial exchange of the products of man's industry, now serves all that is physically good among men. Especially after money was represented by metal, it has produced avarice which, finally, without indulgence, but by its mere possession, and even with the resolution (of the stingy) not to spend it, still contains a power which people believe can sufficiently compensate for the lack of any other power.
    • Kant, Immanuel (1996), pages 181-182
  • [T]his species works intentionally on its own destruction (by war). This, however, does not keep the rational creatures of such a constantly advancing culture, even in the midst of war, from promising to mankind in coming centuries an unequivocal prospect of bliss which will never end.
    • Kant, Immanuel (1996), page 185
  • The man of principles has character. Of him we know definitely what to expect. He does not act on the basis of his instinct, but on the basis of his will. Therefore, without being redundant one can classify characteristics according to a person's faculty of desire (what is practical), as a) his nature, or natural talent, b) his temperament, or disposition, and c) his general character, or mode of thinking.
    • Kant, Immanuel (1996), page 195
  • All... good and useful properties of character have a price in exchange for others which have just as much use. Talent has a market price, since the sovereign or estate-owner can use a talented person in all sorts of ways. Temperament has a fancy price,22 since one can converse well with such a person; he is a pleasant companion. But, character has an inner value[,] and it is above all price.
    • Kant, Immanuel (1996), page 203
  • Nature made women mature early and had them demand gentle and polite treatment from men, so that they would find themselves imperceptibly fettered by a child due to their own magnanimity; and they would find themselves brought, if not quite to morality itself, then at least to that which cloaks it, moral behavior, which is the preparation and introduction to morality.
    • Kant, Immanuel (1996), pages 219-220
  • The woman wants to dominate, the man wants to be dominated[.]
    • Kant, Immanuel (1996), page 220
  • England and France, the two most civilized nations on earth, who are in contrast to each other because of their different characters, are, perhaps chiefly for that reason, in constant feud with one another. Also, England and France, because of their inborn characters, of which the acquired and artificial character is only the result, are probably the only nations who can be assumed to have a particular and, as long as both national characters are not blended by the force of war, unalterable characteristics. That French has become the universal language of conversation, especially in the feminine world, and that English is the most widely used language of commerce among tradesmen, probably reflects the difference in their continental and insular geographic situation.
    • Kant, Immanuel (1996), page 226
  • [T]he first characteristic of the human species is man's ability, as a rational being, to establish character for himself, as well as for the society into which nature has placed him. This ability, however, presupposes an already favorable natural predisposition and an inclination to the good in man, because the evil is really without character (since it is at odds with itself, and since it does not tolerate any lasting principle within itself)
    • Kant, Immanuel (1996), page 246

The Educational Theory of Immanuel Kant (1904)

Quotes of Kant as translated in The Educational Theory of Immanuel Kant (1904) by Edward Franklin Buchner
  • The child must be brought up free (that he allow others to be free). He must learn to endure the restraint to which freedom subjects itself for its own preservation (experience no subordination to his command). Thus he must be disciplined. This precedes instruction. Training must continue without interruption. He must learn to do without things and to be cheerful about it. He must not be obliged to dissimulate, he must acquire immediate horror of lies, must learn so to respect the rights of men that they become an insurmountable wall for him. His instruction must be more negative. He must not learn religion before he knows morality. He must be refined, but not spoiled (pampered). He must learn to speak frankly, and must assume no false shame. Before adolescence he must not learn fine manners ; thoroughness is the chief thing. Thus he is crude longer, but earlier useful and capable.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 3
  • Good and strong will. Mechanism must precede science (learning). Also in morals and religion? Too much discipline makes one narrow and kills proficiency. Politeness belongs, not to discipline, but to polish, and thus comes last.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 9
  • There must be a seed of every good thing in the character of men, otherwise no one can bring it out. Lacking that, analogous motives, honor, etc., are substituted. Parents are in the habit of looking out for the inclinations, for the talents and dexterity, perhaps for the disposition of their children, and not at all for their heart or character.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 13
  • Character means that the person derives his rules of conduct from himself and from the dignity of humanity. Character is the common ruling principle in man in the use of his talents and attributes. Thus it is the nature of his will, and is good or bad. A man who acts without settled principles, with no uniformity, has no character. A man may have a good heart and yet no character, because he is dependent upon impulses and does not act according to maxims. Firmness and unity of principle are essential to character.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 14
  • The more one presupposes that his own power will suffice him to realize what he desires the more practical is that desire. When I treat a man contemptuously, I can inspire him with no practical desire to appreciate my grounds of truth. When I treat any one as worthless, I can inspire him with no desire to do right.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 15
  • The evil effect of science upon men is principally this, that by far the greatest number of those who wish to display a knowledge of it accomplish no improvement at all of the understanding, but only a perversity of it, not to mention that it serves most of them as a tool of vanity.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 52
  • Man's greatest concern is to know how he shall properly fill his place in the universe and correctly understand what he must be in order to be a man.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 53
  • I am an investigator by inclination. I feel a great thirst for knowledge and an impatient eagerness to advance, also satisfaction at each progressive step. There was a time when I thought that all this could constitute the honor of humanity, and I despised the mob, which knows nothing about it. Rousseau set me straight. This dazzling excellence vanishes; I learn to honor men, and would consider myself much less useful than common laborers if I did not believe that this consideration could give all the others a value, to establish the rights of humanity.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 55
  • In the metaphysical elements of aesthetics the various nonmoral feelings are to be made use of; in the elements of moral metaphysics the various moral feelings of men, according to the differences in sex, age, education, and government, of races and climates, are to be employed.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 58
  • In the natural state no concept of God can arise, and the false one which one makes for himself is harmful. Hence the theory of natural religion can be true only where there is no science; therefore it cannot bind all men together.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 60
  • Man has his own inclinations and a natural will which, in his actions, by means of his free choice, he follows and directs. There can be nothing more dreadful than that the actions of one man should be subject to the will of another; hence no abhorrence can be more natural than that which a man has for slavery. And it is for this reason that a child cries and becomes embittered when he must do what others wish, when no one has taken the trouble to make it agreeable to him. He wants to be a man soon, so that he can do as he himself likes.
    • Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 62

Lectures on Ethics (1924)

Lectures on Ethics (original title: Eine Vorlesung Kants über Ethik, 1924), trans. Peter Heath, Cambridge: Cambridge University Press, 1997, 2001.
  • Suicide evokes revulsion with horror, because everything in nature seeks to preserve itself: a damaged tree, a living body, an animal; and in man, then, is freedom, which is the highest degree of life, and constitutes the worth of it, to become now a principium for self-destruction? This is the most horrifying thing imaginable. For anyone who has already got so far as to be master, at any time, over his own life, is also master over the life of anyone else; for him, the door stands open to every crime, and before he can be seized he is ready to spirit himself away out of the world. So suicide evokes horror, in that a man thereby puts himself below the beasts. We regard a suicide as a carcase, whereas we feel pity for one who meets his end through fate.
    • Part II, p. 146
  • A person who already displays … cruelty to animals is also no less hardened towards men. We can already know the human heart, even in regard to animals.
    • Part II, p. 212
  • The more we devote ourselves to observing animals and their behaviour, the more we love them, on seeing how gready they care for their young; in such a context, we cannot even contemplate cruelty to a wolf. Leibnitz put the grub he had been observing back on the tree with its leaf, lest he should be guilty of doing any harm to it. It upsets a man to destroy such a creature for no reason, and this tenderness is subsequendy transferred to man.
    • Part II, pp. 212-213
  • Thus our duties to animals are indirectly duties to humanity.
    • Part II, p. 213


  • Experience without theory is blind, but theory without experience is mere intellectual play.
    • This is declared to be "an old Kantian maxim" in General Systems Vol. 7-8 (1962)‎, p. 11, by the Society for the Advancement of General Systems Theory, but may simply be a paraphrase or summation of Kantian ideas.
    • Kant's treatment of the transcendental logic in the First Critique contains a portion, of which this quote may be an ambiguously worded paraphrase. Kant, claiming that both reason and the senses are essential to the formation of our understanding of the world, writes: "Without sensibility no object would be given to us, and without understanding none would be thought. Thoughts without content are empty, intuitions without concepts are blind (A51/B75)".


  • Do what is right, though the world may perish.
    • This is quoted as Kant in Building Academic Language: Essential Practices for Content Classrooms, Grades 5-12 (2007) by Jeff Zwiers, p. 202, but apparently derives from Kant's arguments in support of the far older Latin proverb Fiat iustitia, pereat mundus — "Do what is right though the world should perish." which was the subject of an essay: "Kant on the Maxim 'Do What Is Right Though the World Should Perish'" by Sissela Bok, in Argumentation 2 (February 1988). There was also a similar latin proverb Fiat iustitia ruat caelum — Let justice be done though the heavens fall.
  • To be is to do.
    • This is usually cited as an ancient maxim, sometimes attributed to Socrates
  • If the truth shall kill them, let them die.

Quotes about Kant

Alphabetized by author
  • If ... the ability to tell right from wrong should turn out to have anything to do with the ability to think, then we must be able to "demand" its exercise from every sane person, no matter how erudite or ignorant, intelligent or stupid, he may happen to be. Kant—in this respect almost alone among the philosophers—was much bothered by the common opinion that philosophy is only for the few, precisely because of its moral implications.
  • The innocent sounding First Thesis, taken seriously, forces us to move our attention away from the individual toward humanity. Since there are no limits to the application of reason, and reason does not work instinctively, but requires "trial, practice, and instruction in order to gradually progress from one level of insight to another," individual human beings do not live long enough to learn the full use of reason. However, we find nature setting a short period for individual lives, but producing a series of generations in which each passes its own accomplishments onto its successor. The only way to make the capability of reasoning consistent with the First Thesis is to assume that rationality is to be fully developed only in the race, not in the individual.
  • The new philosophy of science will prove to be a critical philosophy more subtle and more synthetic than was Kantian philosophy in respect to Newtonian science. Relativistic criticism does not limit itself to a revolution of means of explanation. It is more profoundly revolutionary. It is more génial.
  • Through Kant’s philosophical works, the concept of criticism took on an almost magical meaning for the younger generation [of Germans in the Romantic movement]. To be critical meant to raise thought so far above all constraint that, through the perception of the falseness of constraints, knowledge of the truth takes flight as if by magic.
    • Walter Benjamin, "Der Begriff der Kunstkritik in der deutschen Romantik," Gesammelte Schriften, Volume I.1, p. 51, as quoted in Mark Lilla, “The Riddle of Walter Benjamin” New York Review of Books (25 May 1995)
  • Clearness and vividness in writing often turn on mere specificity. To say that Major André was hanged is clear and definite; to say that he as killed is less definite, because you do not know in what way he was killed; to say that he died is still more indefinite because you do not even know whether his death was due to violence or to natural causes. If we were to use this statement as a varying symbol by which to rank writers for clearness, we might, I think, get something like the following: Swift, Macauley, and Shaw would say that André was hanged. Bradley would say that he was killed. Bosanquet would say that he died. Kant would say that his mortal existence achieved its termination. Hegel would say that a finite determination of infinity had been further determined by its own negation.
    • Bran Blanshard, On Philosophical Style, Manchester University Press, 1954, pp. 30-31.
  • An idealist, Kant separated the phenomenal world from a world of "things in themselves." He believed that science could offer only mechanical explanations, but he affirmed that in areas where such explanations were inadequate, scientific knowledge needed to be supplemented by considering nature as being purposeful.
  • Kant's attitude toward Newton's absolute space is somewhat confused. At times he defends the absoluteness... At other times he presents his own arguments in favor of the relativity of space and motion. ...At any rate the problem of the absoluteness of space and time in classical science refers not to the essence of space and time ( a problem which would degenerate into one of metaphysics, hence would be meaningless to the scientists), but solely to a discussion of those conceptions which are demanded of the world of experience. Hence we may realise that a man ignorant of mechanics is in no position to pass an opinion one way or the other. And Kant's knowledge of Newtonian mechanics was extremely poor, to say the least.
    Thus in his Allgemeine Naturgeschichte und Theorie des Himmels [General History of Nature and Theory of the Heavens], we find him giving incorrect formulæ for the most elementary facts concerning falling bodies. Then again, basing his arguments on what he claims to be the laws of dynamics, he tells us of a nebula which would set itself into rotation owing to its outer parts falling towards the centre and rebounding sideways against the inner parts. But this hypothesis is in flagrant opposition to the principles of dynamics, and had Kant spoken of a man pulling himself up by the bootstraps he would have given expression to no greater absurdity. Whereas this latter statement would violate the principle of action and reaction, Kant's violates the principle of the constancy of the angular momentum of an isolated dynamical system.
    • A. D'Abro, The Evolution of Scientific Thought from Newton to Einstein (1927) footnote, p. 417-418
  • Kant does in fact suggest that some cultures may be more adept than others at teaching their members to use the freedom that is their natural gift. But the social and political spheres can have nothing to do with the giving of this gift in the first place. Kant writes that in the social and political spheres, the goal is to balance competing inclinations through a system of competing coercions; the effect of society and politics on individuals is therefore entirely heteronomous.
    • Will Dudley, Hegel, Nietzsche, and Philosophy: Thinking Freedom (2002), Note 11 to Introduction
  • The great achievement of Kant is to have shown, once for all, that the external world is known to us only as sensation; and that the mind is no mere helpless tabula rasa, the inactive victim of sensation, but a positive agent, selecting and reconstructing experience as experience arrives. We can make subtractions from this accomplishment without injuring its essential greatness… There is something of a severe Scotch Calvinism in this opposition of duty to happiness; Kant continues Luther and the Stoic Reformation:, as Voltaire continues Montaigne and·the Epicurean Renaissance. He represented a stern reaction against the egoism and hedonism in which Helvetius and Holbach had formulated the life of their reckless era, very much as Luther had reacted against the luxury and laxity of Mediterranean Italy. But after a century of reaction against the absolutism of Kant’s ethics, we find ourselves again in a welter of urban sensualism and immorality, of ruthless individualism untempered with democratic conscience or aristocratic honor; and perhaps the day will soon come when a disintegrating civilization will welcome again the Kantian call to duty… After a century of struggle between the idealism of Kant, variously reformed, and the materialism of the Enlightenment, variously redressed, the victory seems to lie with Kant. Philosophy will never again be so naive as in her earlier and simpler days; she must always be different hereafter, and profounder, because Kant lived.
    • Will Durant, Story of Philosophy
  • Where Kant primarily influenced Hayek was in ontology and metaphysics—Hayek’s comprehensive and total view of the world and of life experience—as a number of writers and philosophers, including Tibor Machan, maintain. Machan remarks that Hayek’s “conception of how we are aware of reality manifests his basically Kantian framework.” Hayek, following in a long line of Germanic and idealist philosophers, adopted a view of reality as “the relation between the physical and the sensory world,” in the tradition of Kant, a tradition that, Hayek held, “goes back to Galileo Galilei, who in 1623 had written: ‘I think that these tastes, odors, colors, etc. are nothing else than mere names, but hold their residence solely in the sensitive body, so that, if the animal were removed, any such quality would be abolished and annihilated.’”
    • Alan Ebenstein, Hayek's Journey: The Mind of Friedrich Hayek (2003), Ch. 2. German and Viennese Intellectual Thought
  • The very fact that the totality of our sense experiences is such that by means of thinking (operations with concepts, and the creation and use of definite functional relations between them, and the coordination of sense experiences to these concepts) it can be put in order, this fact is one which leaves us in awe, but which we shall never understand. One may say " the eternal mystery of the world is its comprehensibility." It is one of the great realizations of Immanuel Kant that the setting up of a real external world would be senseless without this comprehensibility.
  • All that is necessary is the statement of a set of rules, since without such rules the acquisition of knowledge in the desired sense would be impossible. One may compare these rules with the rules of a game in which, while the rules themselves are arbitrary, it is their rigidity alone which makes the game possible. However, the fixation will never be final. It will have validity only for a special field of application (i.e. there are no final categories in the sense of Kant).
  • Kant is a sort of highway with lots and lots of milestones. Then all the little dogs come and each deposits his contribution at the milestones.
    • Albert Einstein, quoted in Ilse Rosenthal-Schneider, Reality and Scientific Truth: Discussions With Einstein, Von Laue, and Planck (1980)
  • I am almost amazed that you consider a professional philosopher capable of no confusion in concepts and definitions. Such things are nowhere more at home than among philosophers who are not mathematicians, and Wolff was no mathematician, even though he made cheap compen- diums. Look around among the philosophers of today, among Schelling, Hegel, Nees von Esenbeck, and their like; doesn't your hair stand on end at their definitions? Read in the history of ancient philosophy what kinds of definitions the men of that day, Plato and others, gave (I except Aristotle). But even in Kant it is often not much better; in my opinion his distinction between analytic and synthetic theorems is such a one that either peters out in a triviality or is false.
    • Carl Friedrich Gauss, as quoted in Carl Friedrich Gauss: Titan of Science (2004) by Guy Waldo Dunnington. p. 362
  • In an order so extended as to transcend the comprehension and possible guidance of any single mind, a unified will can indeed hardly determine the welfare of its several members in terms of some particular conception of justice, or according to an agreed scale. Nor is this due merely to the problems of anthropomorphism. [...] The insight that general rules must prevail for spontaneity to flourish, as reaped by Hume and Kant, has never been refuted, merely neglected or forgotten.
  • Then there's philosophy -- supposed to tackle everything. Does it? All any philosopher ever comes out with is exactly what be walked in with -- except for those self-deluded who prove their assumptions by their conclusions, in a circle. Like Kant.
  • [I]t looks in the first moment as though his central concept of the "synthetic judgements a priori" had been completely annihilated by the discoveries of our century. The theory of relativity has... revealed entirely new features of space and time, of which nothing is seen in Kant's a priori forms of pure intuition. The law of causality is no longer applied in quantum theory and the law of conservation of matter is no longer true for the elementary particles. Obviously Kant could not have foreseen the new discoveries, but since he was convinced that his concepts would be "the basis of any future metaphysics that can be called science" it is interesting to see where his arguments have been wrong.
  • With Kant, then, external reality thus drops almost totally out of the picture, and we are trapped inescapably in subjectivity—and that is why Kant is a landmark. Once reason is in principle severed from reality, one then enters a different philosophical universe altogether.
    This interpretive point about Kant is crucial and controversial. An analogy may help drive the point home. Suppose a thinker argued the following: 'I am an advocate of freedom for women. Options and the power to choose among them are crucial to our human dignity. And I am wholeheartedly an advocate of women’s human dignity. But we must understand that a scope of a woman’s choice is confined to the kitchen. Beyond the kitchen’s door she must not attempt to exercise choice. Within the kitchen, however, she has a whole feast of choices—whether to cook or clean, whether to cook rice or potatoes, whether to decorate in blue or yellow. She is sovereign and autonomous. And the mark of a good woman is a well-organized and tidy kitchen.' No one would mistake such a 'thinker for an advocate of woman’s freedom. Anyone would point 'out that there is a whole world beyond the kitchen and that 'freedom is essentially about exercising choice about defining and 'creating one’s place in the world as a whole. The key point about Kant, to draw the analogy crudely, is that he prohibits knowledge of anything outside our skulls. He gives reason lots to do within the skull, and he does advocate a well-organized and tidy mind, but this hardly makes him a champion of reason. The point for any advocate of reason is that there is a whole world outside our skulls, and reason is essentially about knowing it. Kant’s contemporary Moses Mendelssohn was thus prescient in identifying Kant as 'the all-destroyer.'
    • Stephen Hicks, Explaining Postmodernism: Skepticism and Socialism from Rousseau to Foucault, Tempe AZ: Scholargy Press, p. 41-42
  • The brightest object known was the sun. Therefore, the stars were assumed to be like the sun, and distances could be estimated from their apparent faintness. In this way, the conception of a stellar system, isolated in space, was formulated as early as 1750. The author was Thomas Wright... But Wright's speculations went beyond the Milky Way. A single stellar system, isolated in the universe, did not satisfy his philosophical mind. He imagined other, similar systems and, as visible evidence of their existence, referred to the mysterious clouds called "nebulæ." Five years later, Immanuel Kant developed Wright's conception in a form that endured, essentially unchanged, for the following century and a half. Some of Kant's remarks concerning the theory furnish an excellent example or reasonable speculation based on the principle of uniformity. ...The theory, which came to be known as the theory of island universes, found a permanent place in the body of philosophical speculation. ...Toward the end of the nineteenth century... the accumulation of observational data brought into prominence the problem of the status of the nebulæ and, with it, the theory of the island universes as a possible solution.
  • Immanuel Kant was a real pissant who was very rarely stable.
  • Each sensory system first analyzes and deconstructs, then restructures the raw, incoming information to its own built-in connections and rules—shades of Immanuel Kant.
  • Unlike vision, touch, or smell, which are prewired and based on Kantian a priori knowledge, the spatial map presents us with a new type of representation, one based on a combination of a priori knowledge and learning.
  • Kant's critical philosophy is the most elaborate fit of panic in the history of the Earth.
    • Nick Land, The Thirst for Annihilation (1992), p. 1
  • Kant truly says "it is the fate of human reason in speculation to build as rapidly as possible, and only when the edifice is completed to examine the solidity of its foundations." And the source of such carelessness he finds in this, that knowledge often consisting in the analysis of our conceptions, we are led to pay exclusive attention to them, rather than to their origin.
  • Kant (Immanuel), Royal Professor of Morals and Metaphysics in the University of Konigsberg, is considered by his admirers as the greatest philosopher that Germany ever produced. Were we to form an estimate of his merits from the different views that have been given in English of his celebrated system, we certainly should not consider him as entitled to that character; for those views are obscured by new and uncouth terms, and are altogether wrapt up in a style which approaches nearer to jargon than to the luminous composition of a man who thinks with clearness and precision. We readily admit, that it is very difficult to translate a novel system of metaphysics from one language into another; for the translator, to perform his task properly, must be not only a complete master of both languages, but also a profound metaphysician; and not one of the translators or abridgers of the works of Kant into our language appears to us possessed of both these qualities. Despairing, from our scanty knowledge of the German language, of performing ourselves what so many others have failed to perform, we have applied for assistance to an illustrious Frenchman, who has resided many years in Germany, who is master of both languages, who is a profound metaphysician, and whose name, were we at liberty to publish it, would reflect luster upon our Work. From him we have reason to expect a clear and comprehensive view of the Critical Philosophy, as Kant terms his system; but should we be disappointed of our expectation, we shall, under that title, lay before our readers a specimen of the system from the different views of it which have been published in our own tongue.
    • Colin Macfarquhar, George Gleig A. Bell and C. Macfarquhar, Lemma "KANT (Immanuel)," in: Encyclopædia Britannica: Or, A Dictionary of Arts, Sciences, and Miscellaneous Literature, Volume 2, Part 1 (1801), p. 49.
  • What is the attraction of Kuhn’s account of science? It has its roots far back in time, with the biggest self-deluder of all, Immanuel Kant. The hand of Kant lies behind both Bohr and Kuhn. In his epic and epically incomprehensible masterpiece The Critique of Pure Reason (1781), Kant pulled off the grandest intellectual hocus-pocus in scholarly history. […] Kant argued that what have been taken to be features of a mind-independent reality—the structure of space and time, the existence of cause and effect, the law of conservation of energy—are actually imposed upon our experience by the mind itself. We have no justification for thinking that reality is intrinsically spatiotemporal or causally structured. But we are nonetheless eternally destined to experience the world in those terms because those are the intellectual and perceptive structures we must bring to our experience.
    Kant’s argumentation for this Parmenidean thesis is famously obscure, and his writing forbiddingly impenetrable. But the moral he wanted to draw, which goes by the name of transcendental idealism, is easily summarized. I just did. And for whatever reason, this conclusion of Kant’s has been attracting people like a siren’s call ever since. Remarkably, many people just want Kant’s conclusion to be true.
  • As Immanuel Kant pointed out long ago, learning to learn is one of the things that we cannot learn from experience. [see Critique of Pure Reason quote above on à priori and à posteriori knowledge] ...So although sensations give us "occasions" to learn, this cannot be what makes us "able", to learn, because we first must have the additional knowledge that our brains would need, as Kant has said, to "produce representations" and then "to connect" them. Such additional knowledge would also include inborn ways to recognize correlations and other relations among sensations. I suspect that... our brains are already innately endowed with machinery to help us "to compare, to connect, or to separate" objects so that we can represent them as existing in space.
  • Nothing works a more complete and penetrating disaster than every "impersonal" duty, every sacrifice before the Moloch of abstraction.—To think that no one has thought of Kant's categorical imperative as dangerous to life! … What destroys a man more quickly than to work, think and feel without inner necessity, without any deep personal desire, without pleasure—as a mere automaton of duty? That is the recipe for decadence, and no less for idiocy. … Instinct at fault in everything and anything, instinct as a revolt against nature, German decadence as a philosophy—that is Kant!
  • Kant's view of the nature of what is "actually real" remained unaltered throughout his life. Reality is in itself a system of existing thought-essences brought into a unity by teleological relations that are intuitively thought by the Divine intellect, and by this very act of thought posited as real. ...If one... makes Kant either a sceptical agnostic who teaches the unknowableness of things-in-themselves, or a subjective idealist for whom there is no reality in itself at all, he will never be able to make anything of his philosophy. ...Kant is no forbidding or threatening name, but a kindly disposed patron.
    It happens that for many the Critique of Pure Reason is the first philosophical book that they seriously attempt to read. ...the book is not well suited to this purpose. Kant himself would not have recommended it. He did not even write the Prolegomena for pupils, but for future teachers of philosophy. ...They presuppose nothing less than an acquaintance with the entire state of philosophy at the time, with dogmatism and scepticism, with Leibniz and Hume.
    ...Kant's philosophy is the door to the philosophy of our century, and the door to the Kantian philosophy is the Critique of Pure Reason.
  • Individualism, united with altruism, has become the basis of our western civilization. It is the central doctrine of Christianity ('love your neighbor,' say the Scriptures, not 'love your tribe'); and it is the core of all ethical doctrines which have grown from our civilization and stimulated it. It is also, for instance, Kant's central practical doctrine ("always recognize that human individuals are ends, and do not use them as mere means to your end.")
    • Karl Popper, summarizing some of Kant's philosophy, in The Open Society and Its Enemies (1945, p. 102; part of this has sometimes been treated as if it were a direct quote of Kant: Always recognize that human individuals are ends, and do not use them as means to your end.
  • I, for one, while I would not choose to dismiss Kant, am certainly prepared to dismiss his writing style. It was, indeed, in his own day, profitably parodied by Fichte.
    • Stephen K. Roney, “Postmodernist Prose and George Orwell”, Academic Questions (Spring 2002)
  • [T]here used to be in the old days three intellectual arguments for the existence of God, all of which were disposed of by Immanuel Kant in the Critique of Pure Reason; but no sooner had he disposed of those arguments than he invented a new one, a moral argument, and that quite convinced him. He was like many people: in intellectual matters he was skeptical, but in moral matters he believed implicitly in the maxims that he had imbibed at his mother's knee. That illustrates what the psychoanalysts so much emphasize — the immensely stronger hold upon us that our very early associations have than those of later times.
  • From childish fear springs the desire to externalise the ego. Metaphysicians do this in thought: Kant, who, in real life, never went more than ten miles from his native city of Königsberg, maintained that the whole of space existed only in his imagination. This grandiose philosophy was merely the obverse of his practical timidity.
  • Einstein has not — as you sometimes hear — given the lie to Kant’s deep thoughts on the idealization of space and time; he has, on the contrary, made a large step towards its accomplishment.
  • Even when altruism is allowed (as, for example, in Gary Becker's model of rational allocation), it is assumed that the altruistic actions are undertaken because they promote each person's own interests; there are personal gains to the altruist's own welfare, thanks to sympathy for others. No role is given to any sense of commitment about behaving well or to pursuing some selfless objective. All this leaves out, on the one hand, the evil passions that early theorists of capitalism contrasted with selfinterest and, on the other, the social commitments that Kant analyzed in The Critique of Practical Reason and that Adam Smith discussed in The Theory of Moral Sentiments.
  • ”Prussia,” remarked Mirabeau, ”is not a state with an army, but an army with a state.” And the state, which was run with the efficiency and soullessness of a factory, became all; the people were little more than cogs in the machinery. Individuals were taught not only by the kings and the drill sergeants but by the philosophers that their role in life was one of obedience, work, sacrifice and duty. Even Kant preached that duty demands the suppression of human feeling…
    • William L. Shirer, The Rise and Fall of the Third Reich: A History of Nazi Germany, chapter 4: “The Mind of Hitler and the Roots of the Third Reich”
  • Kant's 'discovery' went thus.
    Any property that a real x had, an imaginary x could have, and any property that an imaginary x could have, a real x could have.
    Existence is not a property.
    (Hearty applause, maintained steadily for 200 years so far.)
    • David Stove, Darwinian Fairy Tales (2007)
  • Kant's questions are so strange and arresting that no one who has once heard them ever forgets them. It is just the reverse with his answers to them: no one can ever remember what these are! And there is a simple reason for this: the questions never get answered at all. Once they have served as an excuse for the darkening of sufficient area of wood-pulp, they just get lost.
    • David Stove, The Plato Cult and Other Philosophical Follies (1991). Oxford: Blackwell, p. 53.
  • Kant believed that the concept of time is a prior condition of our minds that affects our experience of the world, but this does not explain why different human societies have had different concepts of time and have assigned different degrees of significance to the temporal aspect of phenomena. ...instead of being a prior condition, our concept of time should be regarded as a consequence of our experience of the world, the result of a long evolution. ...In recent years it has become clear that all our mental abilities are potential capacities which we can only realize in practice by learning how to use them.
  • Today, at any leading American university, a Kant, with all his dithering about God, freedom, and immortality, or even a Hume, wouldn't survive a year in graduate school, much less get hired as an instructor.
    • Tom Wolfe, "In the Land of the Rococo Marxists, Harpers, June 2000

See also

Philosophy of science
ConceptsAnalysisA priori and a posterioriCausalityDemarcation problemFactInductive reasoningInquiryNatureObjectivityObservationParadigmProblem of inductionScientific methodScientific revolutionScientific theory
Related topicsAlchemyEpistemologyHistory of scienceLogicMetaphysicsPseudoscienceRelationship between religion and scienceSociology of scientific knowledge
Philosophers of science PlatoAristotleStoicism
AverroesAvicennaRoger BaconWilliam of Ockham
Francis BaconThomas HobbesRené DescartesGalileo GalileiPierre GassendiIsaac NewtonDavid Hume
Immanuel KantFriedrich SchellingWilliam WhewellAuguste ComteJohn Stuart MillHerbert SpencerWilhelm WundtCharles Sanders PeirceHenri PoincaréPierre DuhemRudolf SteinerKarl Pearson
Alfred North WhiteheadBertrand RussellAlbert EinsteinOtto NeurathC. D. BroadMichael PolanyiHans ReichenbachRudolf CarnapKarl PopperW. V. O. QuineThomas KuhnImre LakatosPaul FeyerabendJürgen HabermasIan HackingBas van FraassenLarry LaudanDaniel Dennett

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