The future is always present, as a promise, a lure and a temptation.

It is impossible to speak in such a way that you cannot be misunderstood.

I have come to the conclusion that Darwinism is not a testable scientific theory, but a metaphysical research programme.

Plato felt that a complete reconstruction of society's political program was needed.

The scientific tradition is distinguished from the pre-scientific tradition by having two layers. Like the latter, it passes on its theories; but it also passes on a critical attitude towards them.

Rationalism is an attitude of readiness to listen to contrary arguments and to learn from experience... of admitting that "I may be wrong and you may be right and, by an effort, we may get nearer the truth."

I have learned more from Hayek than from any other living thinker, except perhaps Alfred Tarski - but not even excepting Russell.