He who loves his neighbor burns his heart, and the heart, like green wood, groans when it burns, and distills itself in tears. There is no point in taking opium; it is better to put salt and vinegar in the soul's wound, for if you fall asleep and no longer feel the pain, then you no longer exist. And the point is to exist.

Science is a cemetary of dead ideas.

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.

Those who say they believe in God and yet neither love nor fear Him, do not in fact believe in Him but in those who have taught them that God exists. Those who believe that they believe in God, but without any passion in their heart, any anguish of mind, without uncertainty, without doubt, without an element of despair even in their consolation, believe only in the God-idea, not in God.

Life is doubt, and faith without doubt is nothing but death.

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

We never know, believe me, when we have succeeded best.