Immanuel Kant

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.

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.

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)."

It is precisely in knowing its limits that philosophy consists.

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.

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.

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.

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

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.

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).

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.

Happiness is not an ideal of reason but of imagination.

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

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.

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.

There can be no doubt that all our knowledge begins with experience.

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.

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

To be is to do.

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.