Just because you believe in something does not mean that it is true.

About God, I cannot accept any concept based on the authority of the Church... As long as I can remember. I have resented mass indoctrination. I cannot prove to you there is no personal God, but if I were to speak of him, I would be a liar. I do not believe in the God of theology who rewards good and punishes evil. His universe is not ruled by wishful thinking, but by immutable laws

Every serious scientific worker is painfully conscious of this involuntary relegation to an ever-narrowing sphere of knowledge, which threatens to deprive the investigator of his broad horizon and degrades him to the level of a mechanic.

What is the meaning of human life, or, for that matter, of the life of any creature? To know the answer to this question means to be religious. You ask: Does it make any sense, then, to pose this question? I answer: The man who regards his fellow creatures as meaningless is not merely unhappy but hardly fit for life.

Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either.

You must be aware that most men (and also not only a few women) are by nature not monogamous. This nature makes itself even more forceful when tradition and circumstance stand in an individual's way.

Man owes his strength in the struggle for existence to the fact that he is a social animal.