Whatever you do, you need courage. Whatever course you decide upon, there is always someone to tell you that you are wrong. There are always difficulties arising that tempt you to believe your critics are right. To map out a course of action and follow it to an end requires some of the same courage that a soldier needs. Peace has its victories, but it takes brave men and women to win them.

Law of Contrariness: Our chief want in life is somebody who shall make us do what we can. Having found them, we shall then hate them for it.

Don't set out to teach theism from your natural history... You spoil both.

But do your work, and I shall know you. Do your work, and you shall reinforce yourself.

With thought, with the ideal, is immortal hilarity, the rose of joy. Round it all the muses sing.

Cause and effect are two sides of one fact.

When we are exalted by ideas, we do not owe this to Plato, but to the idea, to which also Plato was debtor.