The social psychologist of the future will have a number of classes of school children on whom they will try different methods of producing an unshakable conviction that snow is black. When the technique has been perfected, every government that has been in charge of education for more than one generation will be able to control its subjects securely without the need of armies or policemen.

Science may set limits to knowledge, but should not set limits to imagination.

Freedom in general may be defined as the absence of obstacles to the realization of desires.

Philosophy arises from an unusually obstinate attempt to arrive at real knowledge. What passes for knowledge in ordinary life suffers from three defects: it is cocksure, vague and self-contradictory. The first step towards philosophy consists in becoming aware of these defects, not in order to rest content with a lazy scepticism, but in order to substitute an amended kind of knowledge which shall be tentative, precise and self-consistent.

In astronomy, the law of gravitation is plainly better worth knowing than the position of a particular planet on a particular night, or even on every night throughout a year. There are in the law a splendour and simplicity and sense of mastery which illuminate a mass of otherwise uninteresting details. But in history the matter is far otherwise. Historical facts, many of them, have an intrinsic value, a profound interest on their own account, which makes them worthy of study, quite apart from any possibility of linking them together by means of causal laws.

No satisfaction based upon self-deception is solid, and however unpleasant the truth may be, it is better to face it once and for all, to get used to it, and to proceed to build your life in accordance with it.

Everything is vague to a degree you do not realize till you have tried to make it precise.