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

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

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.

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

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.

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

Ingratitude is the essence of vileness.

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.

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.

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

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

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?

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

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

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

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.

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

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.

Science is organized knowledge. Wisdom is organized life.

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

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

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.

Nothing is divine but what is agreeable to reason.

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

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

To be is to do.

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

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

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

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.

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

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

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

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

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

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

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.'

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

Anarchy is law and freedom without force. Despotism is law and force without freedom. Barbarism force without freedom and law. Republicanism is force with freedom and law.

We can judge the heart of a man by his treatment of animals.

If man is not to stifle his human feelings, he must practise kindness towards animals, for 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 appearances are real and negatio; sophistical: All reality must be sensation.

Rules for Happiness something to do someone to love something to hope for.

Mans duty is to improve himself to cultivate his mind and when he finds himself going astray to bring the moral law to bear upon himself.

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

Mans 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.

The death of dogma is the birth of morality.

n action to have moral worth must be done from duty.