Calculus required continuity, and continuity was supposed to require the infinitely little; but nobody could discover what the infinitely little might be.

I am not myself in any degree ashamed of having changed my opinions.

The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt. Even those of the intelligent who believe that they have a nostrum are too individualistic to combine with other intelligent men from whom they differ on minor points.

The more things a man is interested in, the more opportunities of happiness he has and the less he is at the mercy of fate, since if he loses one thing he can fall back upon another.

In the first place a philosophical proposition must be general. It must not deal specially with things on the surface of the earth, or within the solar system, or with any other portion of space and time. . . . This brings us to a second characteristic of philosophical propositions, namely that they must be a priori. A philosophical proposition must be such as can neither be proved nor disproved by empirical evidence. . . . Philosophy, if what has been said is correct, becomes indistinguishable from logic as that word has now come to be used.

Every living thing is a sort of imperialist, seeking to transform as much as possible of its environment into itself.

In emancipation from the fears that beset the slave of circumstance he will experience a profound joy, and through all the vicissitudes of his outward life he will remain in the depths of his being a happy man.