IMMANUEL KANT

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

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

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.

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.'

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.

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

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.

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

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

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.

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

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

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

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.

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.

Science is organized knowledge. Wisdom is organized life.

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

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

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

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

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

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?

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