If a man cannot do brain work without stimulants of any kind, he had better turn to hand work it is an indication on Nature's part that she did not mean him to be a head worker.

Patience and tenacity are worth more than twice their weight of cleverness.

The great thing in the world is not so much to seek happiness as to earn peace and self-respect.

There is no sea more dangerous than the ocean of practical politics none in which there is more need of good pilotage and of a single, unfaltering purpose when the waves rise high.

The struggle for existence holds as much in the intellectual as in the physical world. A theory is a species of thinking, and its right to exist is coextensive with its power of resisting extinction by its rivals.