Immanuel Kant

Dare to know! Have the courage to use your own reason!

Every man is to be respected as an absolute end in himself, and it is a crime against the dignity that belongs to him as a human being, to use him as a mere means for some external purpose.

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

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

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

From timber so crooked as that from which man is carved, nothing entirely straight can be made.

Human reason is by nature architectonic.

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.

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 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.

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.

as to moral feeling, this supposed special sense, the appeal to it is indeed superficial when those who cannot think believe that feeling will help them out, even in what concerns general laws: and besides, feelings which naturally differ infinitely in degree cannot furnish a uniform standard of good and evil, nor has any one a right to form judgments for others by his own feelings...

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

The history of the human race, viewed as a whole may be regarded as the realization of a hidden plan of nature to bring about a political constitution, internally, and for this purpose, also externally perfect, as the only state in which all the capacities implanted by her in mankind can be fully developed.

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

Ours is an age of criticism, to which everything must be subjected. The sacredness of religion, and the authority of legislation, are by many regarded as grounds for exemption from the examination by this tribunal, But, if they are exempted, and cannot lay claim to sincere respect, which reason accords only to that which has stood the test of a free and public examination.

Science is organized knowledge. Wisdom is organized life.

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

That all our knowledge begins with experience, there is indeed no doubt. But although our knowledge originates WITH experience, it does not all arise OUT OF experience.

Out of the crooked timber of humanity no straight thing can ever be made.

So act as to treat humanity, whether in thine own person or in that of any other, in every case as an end withal, never as means only.

There is an imperative which commands a certain conduct immediately, without having as its condition any other purpose to be attained by it. This imperative is Categorical … This imperative may be called that of Morality.

Happiness is not an ideal of reason but of imagination.

I am never to act otherwise than so that I could also will that my maxim should become a universal law.

Nothing in the world—indeed nothing even beyond the world—can possibly be conceived which could be called good without qualification except a good will.

Two things fill the mind with ever new and increasing wonder and awe, the more often and the more seriously reflection concentrates upon them: the starry heaven above me and the moral law within me.