Karl Popper Quotes

Theories are nets cast to catch what we call 'the world': to rationalize, to explain, and to master it. We endeavor to make the mesh ever finer and finer.

I think so badly of philosophy that I don't like to talk about it. ... I do not want to say anything bad about my dear colleagues, but the profession of teacher of philosophy is a ridiculous one. We don't need a thousand of trained, and badly trained, philosophers — it is very silly. Actually most of them have nothing to say.

Should you ever intend to dull the wits of a young man and to incapacitate his brains for any kind of thought whatever, then you cannot do better than give him Hegel to read. For these monstrous accumulations of words that annul and contradict one another drive the mind into tormenting itself with vain attempts to think anything whatever in connection with them, until finally it collapses from sheer exhaustion. Thus any ability to think is so thoroughly destroyed that the young man will ultimately mistake empty and hollow verbiage for real thought. A guardian fearing that his ward might become too intelligent for his schemes might prevent this misfortune by innocently suggesting the reading of Hegel.

As a rule, begin my lectures on Scientific Method by telling my students that scientific method does not exist. ...having been ...the one and only professor of this non-existent subject within the British Commonwealth.

There is an almost universal tendency, perhaps an inborn tendency, to suspect the good faith of a man who holds opinions that differ from our own opinions. … It obviously endangers the freedom and the objectivity of our discussion if we attack a person instead of attacking an opinion or, more precisely, a theory.

It seems to me that I may be living too long. Indeed: my nearest relations have all died, and so have some of my best friends, and even some of my best pupils. However, I do not have a reason to complain. I am grateful and happy to be alive, and still be able to continue with my work, if only just. My work seems to me more important than ever.

[T]here is only one way to science—or to philosophy... to meet a problem, to see its beauty and fall in love with it; to get married to it, and to live with it happily, till death do ye part—unless you should meet another... more fascinating problem, or... obtain a solution. But even if you do... you may... discover, to your delight, the... a whole family of enchanting... perhaps difficult problem children for whose welfare you may work, with a purpose, to the end of your days.

I do not overlook the fact that there are irrationalists who love mankind, and that not all forms of irrationalism engender criminality. But I hold that he who teaches that not reason but love should rule opens up the way for those who rule by hate. (Socrates, I believe, saw something of this when he suggested that mistrust or hatred of argument is related to mistrust or hatred of man).

It seems to me certain that more people are killed out of righteous stupidity than out of wickedness.

I wish to make it clear that ‘history’ in the sense in which most people speak of it simply does not exist; and this is at least one reason why I say that it has no meaning.

Piecemeal social engineering resembles physical engineering in regarding the ends as beyond the province of technology. (All that technology may say about ends is whether they are compatible with each other or realizable.)

The method of learning by trial and error — of learning from our mistakes — seems to be fundamentally the same whether it is practised by lower or by higher animals, by chimpanzees or by men of science.

A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others - not by simply taking over another's opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others

We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant. We should claim that any movement preaching intolerance places itself outside the law, and we should consider incitement to intolerance and persecution as criminal, in the same way as we should consider incitement to murder, or to kidnapping, or to the revival of the slave trade, as criminal.

When I speak of reason or rationalism, all I mean is the conviction that we can learn through criticism of our mistakes and errors, especially through criticism by others, and eventually also through self-criticism. A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others — not by simply taking over another's opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others. The emphasis here is on the idea of criticism or, to be more precise, critical discussion. The genuine rationalist does not think that he or anyone else is in possession of the truth; nor does he think that mere criticism as such helps us achieve new ideas. But he does think that, in the sphere of ideas, only critical discussion can help us sort the wheat from the chaff. He is well aware that acceptance or rejection of an idea is never a purely rational matter; but he thinks that only critical discussion can give us the maturity to see an idea from more and more sides and to make a correct judgement of it.