The single most important decision any of us will ever make is whether or not to believe the universe is friendly.

Without the sense of fellowship with men of like mind... life would have seemed to me empty.

I agree with Schopenhauer that one of the most powerful motives that attracts people to science and art is the longing to escape from everyday life.

[Freud's] sense of reality is less clouded by wishful thinking than is the case with other people and [he combines] the qualities of critical judgment, earnestness and responsibility.

Philosophers play with the word, like a child with a doll.... It does not mean that everything in life is relative.

I do not believe that a man should be restrained in his daily actions by being afraid of punishment after death or that he should do things only because in this way he will be rewarded after he dies. This does not make sense. The proper guidance during the life of a man should be the weight that he puts upon ethics and the amount of consideration that he has for others.

It is open to every man to choose the direction of his striving; and also every man may draw comfort from Lessing's fine saying, that the search for truth is more precious than its possession.