Beggars do not envy millionaires, though of course they will envy other beggars who are more successful.

Ordinary language is totally unsuited for expressing what physics really asserts, since the words of everyday life are not sufficiently abstract. Only mathematics and mathematical logic can say as little as the physicist means to say.

I know a parson who frightened his congregation terribly by telling them the second coming was very imminent indeed, but they were much consoled when they found he was planting trees in his garden.

Orthodoxy is the grave of intelligence, no matter what orthodoxy it may be.

Skilled work, of no matter what kind, is only done well by those who take a certain pleasure in it, quite apart from its utility, either to themselves in earning a living, or to the world through its outcome.

So far I have been speaking of theoretical science, which is an attempt to understand the world. Practical science, which is an attempt to change the world, has been important from the first, and has continually increased in importance, until it has almost ousted theoretical science from men's thoughts.

To the primitive mind, everything is either friendly or hostile; but experience has shown that friendliness and hostility are not the conceptions by which the world is to be understood.