Society is like the air, necessary to breathe but insufficient to live on.

Eternal vigilance is the price of knowledge.

The unforgivable sin is the refusal to pardon.

An ideal cannot wait for its realization to prove its validity.

The need of exercise is a modern superstition, invented by people who ate too much and had nothing to think about.

Man is a gregarious animal, and much more so in his mind than in his body. He may like to go alone for a walk, but he hates to stand alone in his opinions.

It is pathetic to observe how lowly the motives are that religion, even the highest, attributes to the deity... To be given the best morsel, to be remembered, to be praised, to be obeyed blindly and punctiliously - these have been thought points of honor with the gods.