I have often noticed that when people come to understand a mathematical proposition in some other way than that of the ordinary demonstration, they promptly say, "Oh, I see. That's how it must be." This is a sign that they explain it to themselves from within their own system.

One must judge men not by their opinions, but by what their opinions have made of them.

Man…who lives in three places – in the past, in the present, and in the future – can be unhappy if one of these three is worthless. Religion has even added a fourth – eternity.

Theologians always try to turn the Bible into a book without common sense.

The construction of the universe is certainly very much easier to explain than is that of the plant.

Too much is unwholesome.

The celebrated painter Gainsborough got as much pleasure from seeing violins as from hearing them.