Popper Karl Quotes & Sayings

If we wish our civilization to survive we must break with the habit of deference to great men. — Karl Popper

A system such as classical mechanics may be 'scientific' to any degree you like; but those who uphold it dogmatically - believing, perhaps, that it is their business to defend such a successful system against criticism as long as it is not conclusively disproved - are adopting the very reverse of that critical attitude which in my view is the proper one for the scientist. — Karl Popper

All things living are in search of a better world . — Karl Popper

[ ... ] while I felt that the Marxist attitude towards their theory was not at all admirable but was typically dogmatic and had all these properties which the Marxists usually said were characteristic of the churches. So I realized fairly early that Marxism was more of a church than of a science. — Karl Popper

The difference between the amoeba and Einstein is that, although both make use of the method of trial and error elimination, the amoeba dislikes erring while Einstein is intrigued by it. — Karl 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

It is easy to obtain confirmations, or verifications, for nearly every theory-if we look for confirmations. Confirmations should count only if they are the result of risky predictions ... A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice. Every genuine test of a theory is an attempt to falsify it, or refute it. — Karl Popper

[To] interpret Parmenides as a Kant before Kant ... this is exactly what we must do. — Karl Popper

The best thing that can happen to a human being us to find a problem, to fall in love with that problem, and to live trying to solve that problem, unless another problem even more lovable appears. — Karl Popper

The fundamental thing about human languages is that they can and should be used to describe something; and this something is, somehow, the world. To be constantly and almost exclusively interested in the medium - in spectacle-cleaning - is a result of a philosophical mistake. — Karl Popper

When we enter a new situation in life and are confronted by a new person, we bring with us the prejudices of the past and our previous experiences of people. These prejudices we project upon the new person. Indeed, getting to know a person is largely a matter of withdrawing projections; of dispelling the smoke screen of what we imagine he is like and replacing it with the reality of what he is actually like. — Karl 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

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. — Karl Popper

The metaphysical doctrine of determinism simply asserts that all events in this world are fixed, or unalterable, or predetermined. It does not assert that they are known to anybody, or predictable by scientific means. But it asserts that the future is as little changeable as is the past. Everybody knows what we mean when we say that the past cannot be changed. It is in precisely the same sense that the future cannot be changed, according to metaphysical determinism. — Karl Popper

As indicated by our example, methodological nominalism is nowadays fairly generally accepted in the natural sciences. The problems of the social sciences, on the other hand, are still for the most part treated by essentialist methods. This is, in my opinion, one of the main reasons for their backwardness. — Karl Popper

Denying realism amounts to megalomania. — Karl R. Popper

It is the rule which says that the other rules of scientific procedure must be designed in such a way that they do not protect any statement in science against falsification. — Karl Popper

Learning to read, and to a lesser degree, to write, are of course the major events in one's intellectual development. There is nothing to compare with it, since very few people (Helen Keller is the great exception) can remember what it meant for them to learn to speak. — Karl Popper

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. — Karl Popper

There is no reason to believe that a definition necessarily determines the ontological status of the term defined.) — Karl Popper

[The aim of science is] to explain what so far has taken to be an explicans, such as a law of nature. The task of empirical science constantly renews itself. We may go on forever, proceeding to explanations of a higher and higher universality ... — Karl Popper

We should realize that, if [Socrates] demanded that the wisest men should rule, he clearly stressed that he did not mean the learned men; in fact, he was skeptical of all professional learnedness, whether it was that of the philosophers or of the learned men of his own generation, the Sophists. The wisdom he meant was of a different kind. It was simply the realization: how little do I know! Those who did not know this, he taught, knew nothing at all. This is the true scientific spirit. — Karl Popper

Propose theories which can be criticized. Think about possible decisive falsifying experiments-crucial experiments. But do not give up your theories too easily-not, at any rate, before you have critically examined your criticism. — Karl Popper

The most we can say of democracy or freedom is that they give our personal abilities a little more influence on our well-being. — Karl Popper

A theory which is not refutable by any conceivable event is nonscientific. Irrefutability is not a virtue of a theory (as people often think) but a vice. — Karl Popper

Astrologers were greatly impressed, and misled, by what they believed to be confirming evidence-so much so that they were quite unimpressed by any unfavorable evidence. Moreover, by making their interpretations and prophecies sufficiently vague they were able to explain away anything that might have been a refutation of the theory had the theory and the prophecies been more precise. In order to escape falsification they destroyed the testability of their theory. It is a typical soothsayer's trick to predict things so vaguely that the predictions can hardly fail: that they become irrefutable. — Karl Popper

We never know what we are talking about. — Karl Popper

Piecemeal social engineering resembles physical engineering in regarding the ends as beyond the province of technology. — Karl Popper

Appealing to his [Einstein's] way of expressing himself in theological terms, I said: If God had wanted to put everything into the universe from the beginning, He would have created a universe without change, without organisms and evolution, and without man and man's experience of change. But he seems to have thought that a live universe with events unexpected even by Himself would be more interesting than a dead one. — Karl Popper

I have spoken to Einstein and he admitted to me that his theory was in fact no different from the one of Parmenides. — Karl 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

It is impossible to speak in such a way that you cannot be misunderstood. — Karl Popper

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. — Karl Popper

We all have an unscientific weakness for being always in the right, and this weakness seems to be particularly common among professional and amateur politicians. But the only way to apply something like scientific method in politics is to proceed on the assumption that there can be no political move which has no drawbacks, no undesirable consequences. To look out for these mistakes, to find them, to bring them into the open, to analyse them, and to learn from them, this is what a scientific politician as well as a political scientist must do. Scientific method in politics means that the great art of convincing ourselves that we have not made any mistakes, of ignoring them, of hiding them, and of blaming others from them, is replaced by the greater art of accepting the responsibility for them, of trying to learn from them, and of applying this knowledge so that we may avoid them in future. — Karl 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

Bold ideas, unjustified anticipations, and speculative thought, are our only means for interpreting nature: our only organon, our only instrument, for grasping her. And we must hazard them to win our prize. Those among us who are unwilling to expose their ideas to the hazard of refutation do not take part in the scientific game. — Karl Popper

We can all participate in the heritage of man. We all can help to preserve it. And we can all make our own modest contribution to it.
We must not as for more. — Karl Popper

I remained a socialist for several years, even after my rejection of Marxism; and if there could be such a thing as socialism combined with individual liberty, I would be a socialist still. For nothing could be better than living a modest, simple, and free life in an egalitarian society. It took some time before I recognized this as no more than a beautiful dream; that freedom is more important than equality; that the attempt to realize equality endangers freedom; and that, if freedom is lost, there will not even be equality among the unfree. — Karl Popper

With the idol of certainty (including that of degrees of imperfect certainty or probability) there falls one of the defences of obscurantism which bar the way of scientific advance. For the worship of this idol hampers not only the boldness of our questions, but also the rigour and the integrity of our tests. The wrong view of science betrays itself in the craving to be right; for it is not his possession of knowledge, of irrefutable truth, that makes the man of science, but his persistent and recklessly critical quest for truth. — Karl Popper

We must plan for freedom, and not only for security, if for no other reason than only freedom can make security more secure. — Karl Popper

It is a myth that the success of science in our time is mainly due to the huge amounts of money that have been spent on big machines. What really makes science grow is new ideas, including false ideas. — Karl Popper

Now this principle of induction cannot be a purely logical truth like a tautology or an analytic statement ... — Karl Popper

Historically speaking all - or very nearly all - scientific theories originate from myths. — Karl Popper

There is no pure, disinterested, theory-free observation, — Karl Popper

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. - In — Karl Popper

I don't know whether God exists or not ... Some forms of atheism are arrogant and ignorant and should be rejected, but agnosticism - to admit that we don't know and to search - is all right ... When I look at what I call the gift of life, I feel a gratitude which is in tune with some religious ideas of God. However, the moment I even speak of it, I am embarrassed that I may do something wrong to God in talking about God. — Karl Popper

Understanding a theory has, indeed, much in common with understanding a human personality. We may know or understand a man's system of dispositions pretty well; that is to say, we may be able to predict how he would act in a number of different situations. But since there are infinitely many possible situations, of infinite variety, a full understanding of a man's dispositions does not seem to be possible. — Karl Popper

A democratic state begins from the assumption that most of those who gravitate toward power are mediocre and probably immoral. It assumes that we must always protect ourselves from bad government. We must be prepared for the worst leaders even as we hope for the best. And as Karl Popper wrote, this understanding leads to a new approach to power, for it forces us to replace the question: Who shall rule? By the new question: How can we so organize political institutions that bad or incompetent rulers can be prevented from doing too much damage? — Chris Hedges

... 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

Genuine philosophical problems are always rooted outside philosophy and they die if these roots decay. — Karl Popper

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. — Karl Popper

The belief in causality is metaphysical. It is nothing but a typical metaphysical hypostatization of a well-justified methodological rule- the scientist's decision never to abandon his search for laws. The metaphysical belief in causality seems thus more fertile in its various manifestations than any indeterminist physics metaphysics of the kind advocated by Heisenberg. Indeed, we can see that Heisenberg's comments have had a crippling effect on research. Connections which are not far to seek may easily be overlooked if its continually repeated that the search for any such connections is 'meaningless'. — Karl Popper

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. — Karl Popper

The initial stage, the act of conceiving or inventing a theory, seems to me neither to call for logical analysis nor to be susceptible of it. — Karl Popper

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. — Karl Popper

I personally call the type of government which can be removed without violence 'democracy,' and the other, 'tyranny.'. — Karl 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

All nationalism or racialism is evil, and Jewish nationalism is no exception. — Karl Popper

Better our hypotheses die for our errors than ourselves. — Karl Popper

You cannot have a rational discussion with a man who prefers shooting you to being convinced by you. — Karl Popper

Science must begin with myths, and with the criticism of myths. — Karl Popper

A theory is just a mathematical model to describe the observations. — Karl Popper

Contrary to the outstanding work of art, outstanding theory is susceptible to improvements. — Karl Popper

Rationalism is an attitude of readiness to listen to contrary arguments and to learn from experience ... of admitting that "I may be wrong and you may be right and, by an effort, we may get nearer the truth." — Karl Popper

Philosophy is a necessary activity because we, all of us, take a great number of things for granted, and many of these assumptions are of a philosophical character; we act on them in private life, in politics, in our work, and in every other sphere of our lives
but while some of these assumptions are no doubt true, it is likely, that more are false and some are harmful. So the critical examination of our presuppositions
which is a philosophical activity
is morally as well as intellectually important. — Karl Popper

No matter how many instances of white swans we may have observed, this does not justify the conclusion that all swans are white. — Karl Popper

Criticism, I said, is an attempt to find the weak spots in a theory, and these, as a rule, can be found only in the more remote logical consequences which can be derived from it. It is here that purely logical reasoning plays an important part in science. — Karl Popper

I have come to the conclusion that Darwinism is not a testable scientific theory, but a metaphysical research programme ... — Karl Popper

Karl Popper, in The Open Society and Its Enemies, made a comment that sounds almost prophetic now: that the happy, primitive society (which, by the way, never existed) is lost for all those who have eaten of the fruit of the tree of knowledge. The more we try to return to the heroic age of tribalism, Popper warns, the more certainly we will reach the Inquisition, the secret police, and a romanticized gangsterism. But once the existential problems of the individual, who is good by nature, can be blamed on the "evil" society, nothing stands in the way of sheer imagination. The definition of the benevolent society free of all power is only a question of fantasy. — Paul Watzlawick

Reason like science, grows by way of mutual criticism; the only possible way of planning its growth is to develop those institutions that safeguard. the freedom of thought — Karl Popper

Our greatest troubles spring from something that is as admirable as it is dangerous ... our impatience to better the lot of our fellows. — Karl Popper

We have the right not to tolerate the intolerant. We should tolerate even them whenever we can do so without running a great risk; but the risk may become so great that we cannot allow ourselves the luxury. — Karl Popper

I think that we shall have to get accustomed to the idea that we must not look upon science as a 'body of knowledge,' but rather as a system of hypotheses; that is to say, as a system of guesses or anticipations which in principle cannot be justified, but with which we work as long as they stand up to tests, and of which we are never justified in saying that we know they are 'true' or 'more or less certain' or even 'probable.' — Karl Popper

This false epistemology, however, has also led to disastrous consequences. The theory that truth is manifest - that it is there for everyone to see, if only he wants to see it - this theory is the basis of almost every kind of fanaticism. For only the most depraved wickedness can refuse to see the manifest truth; only those who have reason to fear truth conspire to suppress it. — Karl Popper

The idea of self-emancipation through knowledge, which was the basic idea of the Enlightenment, is in itself a powerful enemy of fanaticism; for it makes us try hard to detach ourselves or even to dissociate ourselves from our own ideas (in order to look at them critically) instead of identifying ourselves with them. And the recognition of the sometimes overwhelming historical power of ideas should teach us how important it is to free ourselves from the overpowering influence of false or wrong ideas. In the interests of the quest for truth and of our liberation from errors we have to train ourselves to view our own favourite ideas just as critically as those we oppose. — Karl 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

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). — Karl Popper

To turn Karl [Popper]'s view on its head, it is precisely the abandonment of critical discourse that marks the transition of science. Once a field has made the transition, critical discourse recurs only at moments of crisis when the bases of the field are again in jeopardy. Only when they must choose between competing theories do scientists behave like philosophers. — Thomas Kuhn

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

Good tests kill flawed theories; we remain alive to guess again. — Karl Popper

The use of violence is justified only under a tyranny which makes reforms without violence impossible, and should have only one aim, that is, to bring about a state of affairs which makes reforms without violence possible. — Karl Popper

In philosophy methods are unimportant; any method is legitimate if it leads to results capable of being rationally discussed. What matters is not methods or techniques but a sensitivity to problems, and a consuming passion for them; or, as the Greeks said, the gift of wonder. — Karl Popper

It is often asserted that discussion is only possible between people who have a common language and accept common basic assumptions. I think that this is a mistake. All that is needed is a readiness to learn from one's partner in the discussion, which includes a genuine wish to understand what he intends to say. If this readiness is there, the discussion will be the more fruitful the more the partner's backgrounds differ. — Karl Popper

History has no meaning. — Karl R. Popper

The more we learn about the world, and the deeper our learning, the more conscious, specific, and articulate will be our knowledge of what we do not know, our knowledge of our ignorance — Karl Popper

A rational analysis of the consequences of a decision does not make the decision rational; the consequences do not determine our decision; it is always we who decide. — Karl Popper

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. — Karl Popper

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

It is part of my thesis that all our knowledge grows only through the correcting of our mistakes. — Karl Popper

But it seems to me that what is essential to "creative" or "inventive" thinking is a combination of intense interest in some problem )and thus a readiness to try again and again) with highly critical thinking; with a readiness to attack even those presuppositions which for less critical thought determine the limits of the range from which trials (conjectures) are selected; with an imaginative freedom that allows us to see so far u nsuspected sources of error: possible prejudices in need of critical examination. — Karl Popper

The game of science is, in principle, without end. He who decides one day that scientific statements do not call for any further test, and that they can be regarded as finally verified, retires from the game. — Karl Popper

Our aim must be to make our successive mistakes as quickly as possible. To speed up evolution. — Karl Popper

I would rather find a single causal law than be the king of Persia! — Karl Popper

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

The survival value of intelligence is that it allows us to extinct a bad idea, before the idea extincts us. — Karl 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

A theory that explains everything, explains nothing — Karl Popper

The influence (for good or ill) of Plato's work is immeasurable. Western thought, one might say, has been Platonic or anti-Platonic, but hardly ever non-Platonic. — Karl Popper

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