227 Quotes by Karl Popper

Science is perhaps the only human activity in which errors are systematically criticized and, in time, corrected.

With regards to political enemies Plato had a kill-and-banish principle. ... In interpreting it , modern-day Platonists are clearly disturbed by it, even as they make elaborate attempts to defend Plato.

Every intellectual has a very special responsibility. He has the privilege and the opportunity of studying. In return, he owes it to his fellow men (or 'to society') to represent the results of his study as simply, clearly and modestly as he can. The worst thing that intellectuals can do - the cardinal sin - is to try to set themselves up as great prophets vis-à-vis their fellow men and to impress them with puzzling philosophies. Anyone who cannot speak simply and clearly should say nothing and continue to work until he can do so.

It is wrong to ask who will rule. The ability to vote a bad government out of office is enough. That is democracy.

Ignorance is not a simple lack of knowledge but an active aversion to knowledge, the refusal to know, issuing from cowardice, pride, or laziness of mind.

The history of science is everywhere speculative. It is a marvelous hiatory. It makes you proud to be a human being.

True ignorance is not the absence of knowledge, but the refusal to acquire it.

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.

Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society... then the tolerant will be destroyed, and tolerance with them... We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant.