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

We all remember how many religious wars were fought for a religion of love and gentleness; how many bodies were burned alive with the genuinely kind intention of saving souls from the eternal fire of hell.

A rationalist, as I use the word, is a man who attempts to reach decisions by argument and perhaps, in certain cases, by compromise, rather than by violence. He is a man who would rather be unsuccessful in convincing another man by argument than successful in crushing him by force, by intimidation and threats, or even by persuasive propaganda.

We have become makers of our fate when we have ceased to pose as its prophets.

Every discovery contains an irrational element or a creative intuition.

There can be no ultimate statements science: there can be no statements in science which can not be tested, and therefore none which cannot in principle be refuted, by falsifying some of the conclusions which can be deduced from them.

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