Immanuel Kant

“Nothing is divine but what is agreeable to reason.”

“The only objects of practical reason are therefore those of good and evil. For by the former is meant an object necessarily desired according to a principle of reason; by the latter one necessarily shunned, also according to a principle of reason.”

“It is not God's will merely that we should be happy, but that we should make ourselves happy.”

“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.”

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

“The body is a temple.”

“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.”

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

“Happiness is not an ideal of reason but of imagination.”

“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.”

“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)."”

“There are three juridical attributes that inseparably belong to the citizen by right. These are:”

“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.”

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

“The death of dogma is the birth of morality.”

“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.”

“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.”

“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.”

“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.”

“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”

“Happiness is not an ideal of reason, but of imagination.”

“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”

“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.”

“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.”

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

“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.”

“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.”

“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!”

“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.”

“Experience without theory is blind, but theory without experience is mere intellectual play.”

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

“All natural capacities of a creature are destined to evolve completely to their natural end.”

“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.”

“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.”

“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.”

“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.”

“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.”

“This problem is the most difficult and the last to be solved by mankind.”

“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.”

“Is it reasonable to assume a purposiveness in all the parts of nature and to deny it to the whole?”

“If the truth shall kill them, let them die.”

“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.”

“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.”

“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...”

“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?”

“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.”

“Natural science is throughout either a pure or an applied doctrine of motion.”

“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.”

“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.”

“I have therefore found it necessary to deny knowledge in order to make room for faith.”

“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.”

“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.”

“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.”

“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.”

“Psychologists have hitherto failed to realize that imagination is a necessary ingredient of perception itself.”

“All our knowledge falls with the bounds of experience.”

“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.”

“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.”

“Philosophical knowledge is the knowledge gained by reason from concepts; mathematical knowledge is the knowledge gained by reason from the construction of concepts.”

“It is precisely in knowing its limits that philosophy consists.”

“I have no knowledge of myself as I am, but merely as I appear to myself.”

“Metaphysics has as the proper object of its enquiries three ideas only: God, freedom, and immortality.”

“Human reason is by nature architectonic.”

“All human knowledge begins with intuitions, proceeds from thence to concepts, and ends with ideas.”

“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.”

“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?”

“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.”

“But although all our knowledge begins with experience, it does not follow that it arises from experience.”

“Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.”

“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)”

“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).”

“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.””

“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.”

“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.”

“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.”

“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.”

“Only the descent into the hell of self-knowledge can pave the way to godliness.”

“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.”

“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.”

“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.”

“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.”

“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.”

“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.”

“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.”

“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.”

“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.”

“Thus our duties to animals are indirectly duties to humanity.”

“Rules for happiness: something to do, someone to love, something to hope for.”

“Experience without theory is blind, but theory without experience is mere intellectual play.”

“All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.”

“To be is to do.”

“The death of dogma is the birth of morality.”

“Ingratitude is the essence of vileness.”

“If man makes himself a worm he must not complain when he is trodden on.”

“What can I know? What ought I to do? What can I hope?”

“It is not God's will merely that we should be happy, but that we should make ourselves happy.”

“It is beyond a doubt that all our knowledge begins with experience.”

“Seek not the favor of the multitude; it is seldom got by honest and lawful means. But seek the testimony of few; and number not voices, but weigh them.”

“Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.”

“Out of timber so crooked as that from which man is made nothing entirely straight can be carved.”

“Religion is the recognition of all our duties as divine commands.”

“But although all our knowledge begins with experience, it does not follow that it arises from experience.”

“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?”

“He who is cruel to animals becomes hard also in his dealings with men. We can judge the heart of a man by his treatment of animals.”

“By a lie, a man... annihilates his dignity as a man.”

“Intuition and concepts constitute... the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.”

“In law a man is guilty when he violates the rights of others. In ethics he is guilty if he only thinks of doing so.”

“Immaturity is the incapacity to use one's intelligence without the guidance of another.”

“Always recognize that human individuals are ends, and do not use them as means to your end.”

“I had therefore to remove knowledge, in order to make room for belief.”

“It is not necessary that whilst I live I live happily; but it is necessary that so long as I live I should live honourably.”

“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.'”

“Happiness is not an ideal of reason, but of imagination.”

“Happiness is not an ideal of reason, but of imagination.”

“A categorical imperative would be one which represented an action as objectively necessary in itself, without reference to any other purpose.”

“What can I know? What ought I to do? What can I hope?”

“Science is organized knowledge. Wisdom is organized life.”

“To be is to do.”

“Two things awe me most, the starry sky above me and the moral law within me.”

“Live your life as though your every act were to become a universal law.”

“Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.”

“Thoughts without content are empty, intuitions without concepts are blind.”

“Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.”

“From such crooked wood as that which man is made of, nothing straight can be fashioned.”

“To be is to do.”

“May you live your life as if the maxim of your actions were to become universal law.”

“Act that your principle of action might safely be made a law for the whole world.”

“Intuition and concepts constitute... the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.”

“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.”

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

“Nothing is divine but what is agreeable to reason.”

“The only objects of practical reason are therefore those of good and evil. For by the former is meant an object necessarily desired according to a principle of reason; by the latter one necessarily shunned, also according to a principle of reason.”

“I had therefore to remove knowledge, in order to make room for belief.”

“It is beyond a doubt that all our knowledge begins with experience.”

“He who is cruel to animals becomes hard also in his dealings with men. We can judge the heart of a man by his treatment of animals.”

“All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.”

“Enlightenment is man's release from his self-incurred tutelage. Tutelage is man's inability to make use of his understanding without direction from another. Self-incurred is this tutelage when its cause lies not in lack of reason but in lack of resolution and courage to use it without direction from another. Sapere aude! 'Have courage to use your own reason!'- that is the motto of enlightenment.”

“If the truth shall kill them, let them die.”

“It is beyond a doubt that all our knowledge begins with experience.”

“Experience without theory is blind, but theory without experience is mere intellectual play.”

“All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.”

“To be is to do.”

“Ingratitude is the essence of vileness.”

“If man makes himself a worm he must not complain when he is trodden on.”

“What can I know? What ought I to do? What can I hope?”

“It is not God's will merely that we should be happy, but that we should make ourselves happy.”

“It is beyond a doubt that all our knowledge begins with experience.”

“Seek not the favor of the multitude; it is seldom got by honest and lawful means. But seek the testimony of few; and number not voices, but weigh them.”

“Out of timber so crooked as that from which man is made nothing entirely straight can be carved.”

“Religion is the recognition of all our duties as divine commands.”

“But although all our knowledge begins with experience, it does not follow that it arises from experience.”

“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?”

“He who is cruel to animals becomes hard also in his dealings with men. We can judge the heart of a man by his treatment of animals.”

“By a lie, a man... annihilates his dignity as a man.”

“In law a man is guilty when he violates the rights of others. In ethics he is guilty if he only thinks of doing so.”

“Immaturity is the incapacity to use one's intelligence without the guidance of another.”

“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?”

“Always recognize that human individuals are ends, and do not use them as means to your end.”

“I had therefore to remove knowledge, in order to make room for belief.”

“It is not necessary that whilst I live I live happily; but it is necessary that so long as I live I should live honourably.”

“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.'”

“Happiness is not an ideal of reason, but of imagination.”

“A categorical imperative would be one which represented an action as objectively necessary in itself, without reference to any other purpose.”

“Science is organized knowledge. Wisdom is organized life.”

“Two things awe me most, the starry sky above me and the moral law within me.”

“Live your life as though your every act were to become a universal law.”

“Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.”

“Thoughts without content are empty, intuitions without concepts are blind.”

“Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.”

“From such crooked wood as that which man is made of, nothing straight can be fashioned.”

“May you live your life as if the maxim of your actions were to become universal law.”

“Act that your principle of action might safely be made a law for the whole world.”

“Intuition and concepts constitute... the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.”

“Science is organized knowledge. Wisdom is organized life.”

“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.”

“But although all our knowledge begins with experience, it does not follow that it arises from experience.”

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

“Immaturity is the incapacity to use one's intelligence without the guidance of another.”