The most savage controversies are about matters as to which there is no good evidence either way.

Men fear thought as they fear nothing else on earth - more than ruin, more even than death. Thought is subversive and revolutionary, destructive and terrible, thought is merciless to privilege, established institutions, and comfortable habits; thought is anarchic and lawless, indifferent to authority, careless of the well-tried wisdom of the ages. Thought looks into the pit of hell and is not afraid ... Thought is great and swift and free, the light of the world, and the chief glory of man.

Science has made unrestricted national sovereignty incompatible with human survival. The only possibilities are now world government or death.

The most essential characteristic of scientific technique is that it proceeds from experiment, not from tradition. The experimental habit of mind is a difficult one for most people to maintain; indeed, the science of one generation has already become the tradition of the next

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.

All knowledge, we feel, must be built up upon our instinctive beliefs; and if these are rejected, nothing is left.

A man without a bias cannot write interesting history - if indeed such a man exists.