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.

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.

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

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.

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.

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