Karl R. Popper Quotes & Sayings

From this point of view the question of the scientific status of Darwinian theory - in the widest sense, the theory of trial and error-elimination - becomes an interesting one. I have come to the conclusion that Darwinism is not a testable scientific theory, but a metaphysical research programme - a possible framework for testable scientific theories. — Karl R. Popper

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

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. — Karl R. Popper

I was shocked to have to admit to myself that not only had I accepted a complex theory somewhat uncritically, but that I had also actually noticed quite a bit of what was wrong, in the theory as well as in the practice of communism. But I had repressed this -partly out of loyalty to my friends, partly out of loyalty to "the cause", and partly because there is a mechanism of getting oneself more and more deeply involved: once one has sacrificed one's intellectual conscience over a minor point one doesn't wish to give in too easily; one wishes to justify the self-sacrifice by convincing oneself of the fundamental goodness of the cause, which is seen to outweigh any little moral or intellectual compromise that maybe required. With every such moral or intellectual sacrifice one gets more deeply involved. One becomes ready to back one's moral or intellectual investments in the cause with further investments. It's like being eager to throw good money after bad. — Karl R. Popper

What we need and what we want is to moralize politics, not to politicize morals. — Karl R. Popper

Denying realism amounts to megalomania. — Karl R. Popper

The Vienna Circle was empiricist and phenomenalist, Popper was a critical rationalist. — Karl R. Popper

I have in lectures often described this interesting situation by saying: we never know what we are talking about. For when we propose a theory, or try to understand a theory, we also propose, or try to understand, its logical implications; that is, all those statements which follow from it. But this, as we have just seen, is a hopeless task : there is an infinity of unforeseeable nontrivial statements belonging to the informative content of any theory, and an exactly corresponding infinity of statements belonging to its logical content. We can therefore never know or understand all the implications of any theory, or its full significance
Chapter 7 — Karl R. Popper

Great men may make great mistakes; — Karl R. Popper

Moreover, if we could show, on general logical grounds, that the scientific quest is likely to succeed, one could not understand why anything like success has been so rare in the long history of human endeavours to know more about our world. — Karl R. Popper

The early Greek tribal society resembles in many respects that of peoples like the Polynesians, the Maoris for instance. Small bands of warriors, usually living in fortified settlements, ruled by tribal chiefs or kings, or by aristocratic families, were waging war against one another on sea as well as on land. — Karl R. Popper

Despite my admiration for scientific knowledge, I am not an adherent of scientism. For scientism dogmatically asserts the authority of scientific knowledge; whereas I do not believe in any authority and have always resisted dogmatism; and I continue to resist it, especially in science. I am opposed to the thesis that the scientist must believe in his theory. As far as I am concerned "I do not believe in belief," as E. M. Forster says; and I especially do not believe in belief in science. I believe at most that belief has a place in ethics, and even here only in a few instances. I believe, for example, that objective truth is a value - that is, an ethical value, perhaps the greatest value there is - and that cruelty is the greatest evil. — Karl R. Popper

Never let yourself be goaded into taking seriously problems about words and their meanings. What must be taken seriously are questions of fact, and assertions about facts: theories and hypotheses; the problems they solve; and the problems they raise. — Karl R. Popper

The question of the acceptance of theories should, I propose, be demoted to the status of a minor problem. For science may be regarded as a growing system of problems, rather than as a system of beliefs. And for a system of problems, the tentative acceptance of a theory or a conjecture means hardly more than that it is considered worthy of further criticism. — Karl R. Popper

Conjecture or hypothesis must come before observation or perception: we have inborn expectations; we have latent inborn knowledge, in the form of latent expectations, to be activated by a stimuli to which we react as a rule while engaged in active exploration. All learning is a modification (it may be a refutation)of some prior knowledge and thus, in the last analysis, of some inborn knowledge. — Karl R. Popper

Theology, I still think, is due to lack of faith. — Karl R. Popper

I conjecture that the origin of life and the origin of problems coincide. — Karl R. Popper

I do not believe that human lives may be made the means for satisfying an artist's desire for self-expression. We must demand, rather, that every man should be given, if he wishes, the right to model his life himself, as far as this does not interfere too much with others. Much as I may sympathize with the aesthetic impulse, I suggest that the artist might seek expression in another material. Politics, I demand, must uphold equalitarian and individualistic principles; dreams of beauty have to submit to the necessity of helping men in distress, and men who suffer injustice; and to the necessity of constructing institutions to serve such purposes. — Karl R. Popper

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

When the poet or the performer composes or recites he is deeply moved, and indeed possessed (not only by the god but also) by the message; for example, by the scenes he describes. And the work, rather than merely his emotional state, induces similar emotions in his audience. — Karl R. Popper

I don't think highly of the theoretical or explanatory power of of the theory of evolution. But I think that an evolutionary approach to biological problems is inescapable, and also that in so desperate a problem situation we must clutch gratefully even at a straw. So, I propose, to start, that we regard the human mind quite naively as if it were a highly developed bodily organ, and that we ask ourselves, as we might with respect to a sense organ, what it contributes to the household of the organism. — Karl R. Popper

All life is problem solving — Karl R. Popper

Every 'good' scientific theory is a prohibition: it forbids certain things to happen. The more a theory forbids, the better it is. — Karl R. Popper

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. — Karl R. Popper

Although I have known sorrow and great sadness, as is everybody's lot, I don't think that I have had an unhappy hour as a philosopher since we returned to England. I have worked hard, and I have often got deep into insoluble difficulties. But I have been most happy in finding new problems, in wrestling with them, and in making some progress. This, or so I feel, is the best life. It seems to me infinitely better than the life of mere contemplation (to say nothing of divine self-contemplation) which Aristotle recommends as the best. It is a completely restless life, but it is highly self-contained/autark in Plato's sense, although no life, of course, can be fully autark. — Karl R. Popper

The future depends on ourselves, and we do not depend on any historical necessity. — Karl R. Popper

... if we are uncritical we shall always find what we want: we shall look for, and find, confirmations, and we shall look away from, and not see, whatever might be dangerous to our pet theories. In this way it is only too easy to obtain what appears to be overwhelming evidence in favor of a theory which, if approached critically, would have been refuted. In order to make the method of selection by elimination work, and to ensure that only the fittest theories survive, their struggle for life must be made severe for them. — Karl R. Popper

I suggest that the emergence of descriptive language is at the root of the human power of imagination, of human inventiveness, and therefore the emergence of world 3. — Karl R. Popper

If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them. — Karl R. Popper

Again, we cannot search the whole world in order to make sure that nothing exists which the law forbids. Nevertheless, both kinds of strict statements, strictly existential and strictly universal, are in principle empirically decidable, each, however, in one way only: they are unilaterally decidable. Whenever it is found that something exists here or there, a strictly existential statement may thereby be verified, or a universal one falsified. — Karl R. Popper

This is why the conflict between rationalism and irrationalism has become the most important intellectual, and perhaps even moral, issue of our time. — Karl R. Popper

History has no meaning. — Karl R. Popper

Relativism is one of the many crimes committed by intellectuals. It is a betrayal of reason and of humanity. — Karl R. Popper

in the field of ethics, of moral knowledge, it was approached by Kant with his principle of autonomy. This principle expresses his realization that we must not accept the command of an authority, however exalted, as the basis of ethics. For whenever we are faced with a command by an authority, it is for us to judge, critically, whether it is moral or immoral to obey. The authority may have power to enforce its commands, and we may be powerless to resist. But if we have the physical power of choice, then the ultimate responsibility remains with us. It is our own critical decision whether to obey a command; whether to submit to an authority. — Karl R. Popper

The reality of time and change seemed to me the crux of realism. — Karl R. Popper

The essential feature of dualist-interactionism is that the mind and brain are independent entities...and that they interact by quantum physics. — Karl R. Popper