Immanuel Kant Quotes

200 Quotes on Life, Freedom, and the Beauty of Small Details to Inspire and Guide You

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.
Variant: All human knowledge begins with intuitions, proceeds from thence to concepts, and ends with ideas.
Source: Critique of Pure Reason (1781; 1787)

Part II, p. 212
Lectures on Ethics (1924)

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)".
Disputed

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

Preface, Tr. Bax (1883)
Metaphysical Foundations of Natural Science (1786)

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

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 60
The Educational Theory of Immanuel Kant (1904)

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

As quoted in Gems of Thought (1888) edited by Charles Northend

Preface to the Second Edition [Tr. F. Max Müller], (New York, 1900), p. 690; as cited in: Robert Edouard Moritz, Memorabilia mathematica or, The philomath's quotation-book https://openlibrary.org/books/OL14022383M/Memorabilia_mathematica, Published 1914. p. 10
Critique of Pure Reason (1781; 1787)

Book IV, Part 1, Section 1, “The Christian religion as a learned religion”
Religion within the Limits of Reason Alone (1793)

What is Enlightenment? (1784)

Ich soll niemals anders verfahren als so, dass ich auch wollen könne, meine Maxime solle ein allgemeines Gesetz werden.
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.
Groundwork of the Metaphysics of Morals (1785)

[N]ur die Höllenfahrt des Selbsterkenntnisses bahnt den Weg zur Vergötterung ...
Ak 6:441
Metaphysics of Morals (1797)

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 13
The Educational Theory of Immanuel Kant (1904)
Context: 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, # 14
The Educational Theory of Immanuel Kant (1904)
Context: 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.

Book IV, Part 2, Section 4
Religion within the Limits of Reason Alone (1793)
Context: 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

As quoted in German Thought, From The Seven Years' War To Goethe's Death : Six Lectures (1880) by Karl Hillebrand, p. 208
Context: 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.

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 9
The Educational Theory of Immanuel Kant (1904)
Context: 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.

Original: (de) Wer sich aber zum Wurm macht, kann nachher nicht klagen, dass er mit Füßen getreten wird.
Source: Part two: Metaphysical Principles of Virtue page 98. note: Metaphysics of Morals (1797)

Metaphysical Elements of Ethics (1780). Translated by Thomas Kingsmill Abbott, translation available at Philosophy.eserver.org http://philosophy.eserver.org/kant/metaphys-elements-of-ethics.txt. From section "Preliminary Notions of the Susceptibility of the Mind for Notions of Duty Generally", Part C ("Of love to men")

Third Thesis
Idea for a Universal History from a Cosmopolitan Point of View (1784)
Context: 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.

Groundwork of the Metaphysics of Morals (1785)
Context: 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?

What is Enlightenment? (1784)
Context: 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.

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

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 55
The Educational Theory of Immanuel Kant (1904)
Context: 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.

B 374
Critique of Pure Reason (1781; 1787)
Context: 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.

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 15
The Educational Theory of Immanuel Kant (1904)
Context: 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.

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
Context: 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.

Critique of Practical Reason (1788)
Context: 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

As quoted in German Thought, From The Seven Years' War To Goethe's Death : Six Lectures (1880) by Karl Hillebrand, p. 208
Context: [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.

Free translation, as quoted by Edwin Powell Hubble, The Realm of the Nebulae (1936)
An Original Theory or New Hypothesis of the Universe (1750)
Context: 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.

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

What is Enlightenment? (1784)
Context: 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!

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 3
The Educational Theory of Immanuel Kant (1904)
Context: 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.

Immanuel Kant, The Metaphysics of Ethics by Immanuel Kant, trans. J.W. Semple, ed. with Iintroduction by Rev. Henry Calderwood (Edinburgh: T. & T. Clark, 1886) (3rd edition). Chapter: GENERAL DIVISION OF JURISPRUDENCE. http://oll.libertyfund.org/?option=com_staticxt&staticfile=show.php%3Ftitle=1443&chapter=56215&layout=html&Itemid=27
Context: Freedom is the alone unoriginated birthright of man, and belongs to him by force of his humanity; and is independence on the will and co-action of every other in so far as this consists with every other person’s freedom.

Part III : Selection on Education from Kant's other Writings, Ch. I Pedagogical Fragments, # 3
The Educational Theory of Immanuel Kant (1904)
Context: 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.

Introduction
Idea for a Universal History from a Cosmopolitan Point of View (1784)
Context: 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.

Groundwork of the Metaphysics of Morals (1785)
Context: 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.

The Educational Theory of Immanuel Kant (1904)
Context: 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

Seventh Thesis
Idea for a Universal History from a Cosmopolitan Point of View (1784)
Context: 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.

What is Enlightenment? (1784)
Context: 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!

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

Free translation, as quoted by Edwin Powell Hubble, The Realm of the Nebulae (1936)
An Original Theory or New Hypothesis of the Universe (1750)
Context: 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.

Introduction
Idea for a Universal History from a Cosmopolitan Point of View (1784)
Context: 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.

Groundwork of the Metaphysics of Morals (1785)
Context: 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.

Free translation, as quoted by Edwin Powell Hubble, The Realm of the Nebulae (1936)
An Original Theory or New Hypothesis of the Universe (1750)
Context: 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.

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
Religion within the Limits of Reason Alone (1793)
Context: 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 https://en.wiktionary.org/wiki/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.

Context: 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

Source: What is Enlightenment?

Source: Critique of Pure Reason

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.
Source: Idea for a Universal History with a Cosmopolitan Purpose

As quoted in Faith Or Fact (1897) by Henry Moorehouse Taber, p. 86

Source: An Answer to the Question: What Is Enlightenment?

A 51, B 75
Source: Critique of Pure Reason (1781; 1787)
Context: 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.

What is Enlightenment? (1784)
Variant: Have the courage to use your own reason- That is the motto of enlightenment.
Source: Groundwork of the Metaphysics of Morals
Context: 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.