227 Quotes by Karl Popper

The true Enlightenment thinker, the true rationalist, never wants to talk anyone into anything. No, he does not even want to convince; all the time he is aware that he may be wrong. Above all, he values the intellectual independence of others too highly to want to convince them in important matters. He would much rather invite contradiction, preferably in the form of rational and disciplined criticism. He seeks not to convince but to arouse – to challenge others to form free opinions.

Historically speaking all – or very nearly all – scientific theories originate from myths.

The quest for precision is analogous to the quest for certainty, and both should be abandoned.

I hold that he who teaches that not reason but love should rule opens up the way for those who rule by hate.

The point is that, whenever we propose a solution to a problem, we ought to try as hard as we can to overthrow our solution, rather than defend it. Few of us, unfortunately, practice this precept; but other people, fortunately, will supply the criticism for us if we fail to supply it ourselves.

Evolution is not a fact. Evolution doesn’t even qualify as a theory or as a hypothesis. It is a metaphysical research program, and it is not really testable science.

And it implies that if we respect truth, we must search for it by persistently searching for our errors: by indefatigable rational criticism, and self-criticism.

But it is certainly not possible to insist on one hand that the formalism is complete and to insist on the other hand that its application to ‘the actual’ actually demands a step which cannot be derived from it.

We must regard all laws or theories as hypothetical or conjectural; that is, as guesses.