Love cannot exists as a duty; to tell a child that it ought to love its parents and its brother and sisters is utterly useless, if not worse.

Who ever heard a theologian preface his creed, or a politician conclude his speech with an estimate of the probable error of his opinion?

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

We know too much and feel too little. At least, we feel too little of those creative emotions from which a good life springs.

There was, I think, never any reason to believe in any innate superiority of the male, except his superior muscle.

The true spirit of delight...is to be found in mathematics as surely as in poetry.

It is for this reason that rationality is of supreme importance to the well-being of the human species...even more, in those less fortunate times in which it is despised and rejected as the vain dream of men who lack the virility to kill where they cannot agree.