Morally, a philosopher who uses his professional competence for anything except a disinterested search for truth is guilty of a kind of treachery.

The observer, when he seems to himself to be observing a stone, is really, if physics is to be believed, observing the effects of the stone upon himself.

Worry is a form of fear, and all forms of fear produce fatigue. A man who has learned not to feel fear will find the fatigue of daily life enormously diminished.

When conscious activity is wholly concentrated on some one definite purpose, the ultimate result, for most people, is lack of balance accompanied by some form of nervous disorder.

Plato has dramatic strength ... but is quite unaware of the strength of the argument against his position ... and allows himself to be grossly unfair in arguing against it.

No great achievement is possible without persistent work.

[Regarding] the convention that clergymen are more virtuous than other men. Any average selection of mankind, set apart and told that it excels the rest in virtue, must tend to sink below the average.