I would never die for my beliefs because I might be wrong.

Our great democracies still tend to think that a stupid man is more likely to be honest than a clever man.

While the dogmatist is harmful, the sceptic is useless ...; one is certain of knowing, the other of not knowing. What philosophy should dissipate is certainty, whether of knowledge or of ignorance. Knowledge is not so precise a concept as is commonly thought. Instead of saying 'I know this', we ought to say 'I more or less know something more or less like this'. ... Knowledge in practical affairs has not the certainty or the precision of arithmetic.

Collective fear stimulates herd instinct, and tends to produce ferocity toward those who are not regarded as members of the herd.

Civilized people cannot fully satisfy their sexual instinct without love.

There is no greater reason for children to honour parents than for parents to honour children except, that while the children are young, the parents are stronger than children.

Fear is the parent of cruelty, and therefore it is no wonder if cruelty and religion have gone hand-in-hand. It is because fear is at the basis of those two things. In this world we can now begin a little to understand things, and a little to master them by the help of science, which has forced its way step by step against the Christian religion, against the churches, and against the opposition of all the old precepts.