The skeptic does not mean him who doubts, but him who investigates or researches, as opposed to him who asserts and thinks that he has found.

There is no true love save in suffering, and in this world we have to choose either love, which is suffering, or happiness. Man is the more man - that is, the more divine - the greater his capacity for suffering, or rather, for anguish.

My religion is to seek for truth in life and for life in truth, even knowing that I shall not find them while I live.

The supreme triumph of reason is to cast doubt upon its own validity.

A man does not die of love or his liver or even of old age; he dies of being a man.

If a philosopher is not a man, he is anything but a philosopher; he is above all a pedant, and a pedant is a caricature of a man.

Only he who attempts the absurd is capable of achieving the impossible.