If you have a good scientific imagination, you can think of all sorts of things that might be true, and that’s the essence of science. You first think of something that might be true — then you look to see if it is, and generally it isn’t.

Bertrand Russell (1872-1970) English mathematician and philosopher

Interview by Woodrow Wyatt, BBC TV (1959)

Collected in Bertrand Russell's BBC Interviews (1959) [UK] and Bertrand Russell Speaks His Mind (1960) [US].