Knowledge shrinks as wisdom grows.

If a dog jumps into your lap, it is because he is fond of you; but if a cat does the same thing, it is because your lap is warmer.

Civilization advances by extending the number of important operations which we can perform without thinking of them.

True courage is not the brutal force of vulgar heroes, but the firm resolve of virtue and reason.

No one who achieves success does so without acknowledging the help of others. The wise and confident acknowledge this help with gratitude.

It is the business of the future to be dangerous; and it is among the merits of science that it equips the future for its duties.

It takes an extraordinary intelligence to contemplate the obvious.

No one who achieves success does so without acknowledging the help of others. The wise and confident acknowledge this help with gratitude.

Fools act on imagination without knowledge, pedants act on knowledge without imagination.

The total absence of humor from the Bible is one of the most singular things in all literature.

Not ignorance, but ignorance of ignorance, is the death of knowledge.

In formal logic, a contradiction is the signal of defeat, but in the evolution of real knowledge it marks the first step in progress toward a victory.