“This has been my life. I have found it worth living, and would gladly live it again if the chance were offered to me.”

I say quite deliberately that the Christian religion, as organized in its churches, has been and still is the principal enemy of moral progress in the world.

One of the most powerful of all our passions is the desire to be admired and respected.

Mathematics rightly viewed possesses not only truth but supreme beauty.

One of the symptoms of an approaching nervous breakdown is the belief that one’s work is terribly important.

Patriots always talk of dying for their country but never of killing for their country.

The wise man thinks about his troubles only when there is some purpose in doing so; at other times he thinks about other things, or, if it is night, about nothing at all.

A happy life must be to a great extent a quiet life, for it is only in an atmosphere of quiet that true joy can live.

Whoever wishes to become a philosopher must learn not to be frightened by absurdities.

In all affairs, it’s a healthy thing now and then to hang a question mark on the things you have long taken for granted.

We know very little, and yet it is astonishing that we know so much, and still more astonishing that so little knowledge can give us so much power.

And if there were a God, I think it very unlikely that he would have such an uneasy vanity as to be offended by those who doubt his existence.

The secret of happiness is to face the fact that the world is horrible, horrible, horrible.

No one gossips about other people’s secret virtues.

The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.

Is there any knowledge in the world that is so certain that no reasonable man could doubt it?

Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search for knowledge, and unbearable pity for the suffering of mankind.