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.

The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd.

There have been poverty, pestilence, and famine, which were due to man's inadequate mastery of nature. There have been wars, oppressions and tortures which have been due to men's hostility to their fellow men.

War does not determine who is right - only who is left.

I wish to propose for the reader's favourable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine in question is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true.

Modern technique has made it possible for leisure, within limits, to be not the prerogative of small privileged classes, but a right evenly distributed throughout the community. The morality of work is the morality of slaves, and the modern world has no need of slavery.

There can't be a practical reason for believing something that is not true.