Life is the faculty of spontaneous activity, the awareness that we have powers.

...as soon as we examine suicide from the standpoint of religion we immediately see it in its true light. We have been placed in this world under certain conditions and for specific purposes. But a suicide opposes the purpose of his creator; he arrives in the other world as one who has deserted his post; he must be looked upon as a rebel against God. God is our owner; we are his property; his providence works for our good.

In every department of physical science there is only so much science, properly so-called, as there is mathematics.

Every human being should always be treated as an end and never as a mere instrument.

Have the courage to use your own reason- That is the motto of enlightenment. "Foundations of the Metaphysics of Morals" (1785)

For how is it possible, says that acute man, that when a concept is given me, I can go beyond it and connect with it another which is not contained in it, in such a manner as if that latter necessarily belonged to the former?

Three things tell a man: his eyes, his friends and his favorite quotes