The very best proof that something can be done is that someone has already done it.

Suppose atomic bombs had reduced the population of the world to one brother and sister; should they let the human race die out?

We must be sceptical even of our scepticism.

Nothing of importance is ever achieved without discipline. I feel myself sometimes not wholly in sympathy with some modern educational theorists, because I think that they underestimate the part that discipline plays. But the discipline you have in your life should be one determined by your own desires and your own needs, not put upon you by society or authority.

It is only theory that makes men completely incautious.

The psychology of adultery has been falsified by conventional morals, which assume, in monogamous countries, that attraction to one person cannot coexist with affection for another. Everybody knows that this is untrue.

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