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Karl Popper - Quotes

All things living are in search of a better world.
Popper, Karl. In Search of a Better World. 1984.

The belief in a political Utopia is especially dangerous. This is possibly connected with the fact that the search for a better world, like the investigation of our environment, is (if I am correct) one of the oldest and most important of all the instincts.
Popper, Karl. In Search of a Better World. 1984.

Our aim as scientists is objective truth; more truth, more interesting truth, more intelligible truth. We cannot reasonably aim at certainty. Once we realize that human knowledge is fallible, we realize also that we can never be completely certain that we have not made a mistake.
Popper, Karl. In Search of a Better World. 1984.

There are uncertain truths — even true statements that we may take to be false — but there are no uncertain certainties. Since we can never know anything for sure, it is simply not worth searching for certainty; but it is well worth searching for truth; and we do this chiefly by searching for mistakes, so that we have to correct them.
Popper, Karl. In Search of a Better World. 1984.

Why do I think that we, the intellectuals, are able to help? Simply because we, the intellectuals, have done the most terrible harm for thousands of years. Mass murder in the name of an idea, a doctrine, a theory, a religion — that is all our doing, our invention: the invention of the intellectuals. If only we would stop setting man against man — often with the best intentions — much would be gained. Nobody can say that it is impossible for us to stop doing this.
Popper, Karl. In Search of a Better World. 1984.

Always remember that it is impossible to speak in such a way that you cannot be misunderstood: there will always be some who misunderstand you.
Popper, Karl. Unended Quest: An Intellectual Autobiography. 1976.

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. For this, indeed, is the main source of our ignorance — the fact that our knowledge can be only finite, while our ignorance must necessarily be infinite.
Popper, Karl. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963.

I believe it is worthwhile trying to discover more about the world, even if this only teaches us how little we know.
Popper, Karl. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963.

Science must begin with myths, and with the criticism of myths.
Popper, Karl. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963.

Science is one of the very few human activities — perhaps the only one — in which errors are systematically criticized and fairly often, in time, corrected.
Popper, Karl. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963.

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.
Popper, Karl. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963.

It seems to me certain that more people are killed out of righteous stupidity than out of wickedness.
Popper, Karl. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963.

There are all kinds of sources of our knowledge; but none has authority ... The fundamental mistake made by the philosophical theory of the ultimate sources of our knowledge is that it does not distinguish clearly enough between questions of origin and questions of validity.
Popper, Karl. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963.

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.
Popper, Karl and Patrick Camiller (Translator). All Life is Problem Solving. 1958.

Although I consider our political world to be the best of which we have any historical knowledge, we should beware of attributing this fact to democracy or to freedom. Freedom is not a supplier who delivers goods to our door. Democracy does not ensure that anything is accomplished — certainly not an economic miracle. It is wrong and dangerous to extol freedom by telling people that they will certainly be all right once they are free. How someone fares in life is largely a matter of luck or grace, and to a comparatively small degree perhaps also of competence, diligence, and other virtues. The most we can say of democracy or freedom is that they give our personal abilities a little more influence on our well-being.
Popper, Karl and Patrick Camiller (Translator). All Life is Problem Solving. 1958.

It is wrong to think that belief in freedom always leads to victory; we must always be prepared for it to lead to defeat. If we choose freedom, then we must be prepared to perish along with it.
Popper, Karl and Patrick Camiller (Translator). All Life is Problem Solving. 1958.

We do not choose political freedom because it promises us this or that. We choose it because it makes possible the only dignified form of human coexistence, the only form in which we can be fully responsible for ourselves. Whether we realize its possibilities depends on all kinds of things — and above all on ourselves.
Popper, Karl and Patrick Camiller (Translator). All Life is Problem Solving. 1958.

Not only do I hate violence, but I firmly believe that the fight against it is not hopeless. I realize that the task is difficult.
Popper, Karl. Utopia and Violence. 1947.

The spirit of Hitlerism won its greatest victory over us when, after its defeat, we used the weapons which the threat of Nazism had induced us to develop.
Popper, Karl. Utopia and Violence. 1947.

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.
Popper, Karl. Utopia and Violence. 1947.

We all remember how many religious wars were fought for a religion of love and gentleness; how many bodies were burned alive with the genuinely kind intention of saving souls from the eternal fire of hell. Only if we give up our authoritarian attitude in the realm of opinion, only if we establish the attitude of give and take, of readiness to learn from other people, can we hope to control acts of violence inspired by piety and duty.
Popper, Karl. Utopia and Violence. 1947.

There are many difficulties impeding the rapid spread of reasonableness. One of the main difficulties is that it always takes two to make a discussion reasonable. Each of the parties must be ready to learn from the other. You cannot have a rational discussion with a man who prefers shooting you to being convinced by you.
Popper, Karl. Utopia and Violence. 1947.

Do not allow your dreams of a beautiful world to lure you away from the claims of men who suffer here and now. Our fellow men have a claim to our help; no generation must be sacrificed for the sake of future generations, for the sake of an ideal of happiness that may never be realised.
Popper, Karl. Utopia and Violence. 1947.

If in this book harsh words are spoken about some of the greatest among the intellectual leaders of mankind, my motive is not, I hope, the wish to belittle them. It springs rather from my conviction that, if our civilization is to survive, we must break with the habit of deference to great men. Great men may make great mistakes; and as the book tries to show, some of the greatest leaders of the past supported the perennial attack on freedom and reason. Their influence, too rarely challenged, continues to mislead those on whose defence civilization depends, and to divide them. The responsibility of this tragic and possibly fatal division becomes ours if we hesitate to be outspoken in our criticism of what admittedly is a part of our intellectual heritage. By reluctance to criticize some of it, we may help to destroy it all.
Popper, Karl. The Open Society and Its Enemies. 1945.

I see now more clearly than ever before that even our greatest troubles spring from something that is as admirable and sound as it is dangerous — from our impatience to better the lot of our fellows. For these troubles are the by-products of what is perhaps the greatest of all moral and spiritual revolutions of history, a movement which began three centuries ago. It is the longing of uncounted unknown men to free themselves and their minds from the tutelage of authority and prejudice. It is their attempt to build up an open society which rejects the absolute authority to preserve, to develop, and to establish traditions, old or new, that measure up to their standards of freedom, of humaneness, and of rational criticism. It is their unwillingness to sit back and leave the entire responsibility for ruling the world to human or superhuman authority,and their readiness to share the burden of responsibility for avoidable suffering, and to work for its avoidance. This revolution has created powers of appalling destructiveness; but they may yet be conquered.
Popper, Karl. The Open Society and Its Enemies. 1945.

This civilization has not yet fully recovered from the shock of its birth — the transition from the tribal or "enclosed society," with its submission to magical forces, to the 'open society' which sets free the critical powers of man.
Popper, Karl. The Open Society and Its Enemies. 1945.

We may become the makers of our fate when we have ceased to pose as its prophets.
Popper, Karl. The Open Society and Its Enemies. 1945.

What a monument of human smallness is this idea of the philosopher king. What a contrast between it and the simplicity of humaneness of Socrates, who warned the statesmen against the danger of being dazzled by his own power, excellence, and wisdom, and who tried to teach him what matters most — that we are all frail human beings. What a decline from this world of irony and reason and truthfulness down to Plato's kingdom of the sage whose magical powers raise him high above ordinary men; although not quite high enough to forgo the use of lies, or to neglect the sorry trade of every shaman — the selling of spells, of breeding spells, in exchange for power over his fellow-men.
Popper, Karl. The Open Society and Its Enemies. 1945.

The open society is one in which men have learned to be to some extent critical of taboos, and to base decisions on the authority of their own intelligence.
Popper, Karl. The Open Society and Its Enemies. 1945.

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 against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them.
Popper, Karl. The Open Society and Its Enemies. 1945.

We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant.
Popper, Karl. The Open Society and Its Enemies. 1945.

We must plan for freedom, and not only for security, if for no other reason than only freedom can make security more secure.
Popper, Karl. The Open Society and Its Enemies. 1945.

No rational argument will have a rational effect on a man who does not want to adopt a rational attitude.
Popper, Karl. The Open Society and Its Enemies. 1945.

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.
Popper, Karl. The Open Society and Its Enemies. 1945.

...the attempt to make heaven on earth invariably produces hell. It leads to intolerance. It leads to religious wars, and to the saving of souls through the inquisition. And it is, I believe, based on a complete misunderstanding of our moral duties. It is our duty to help those who need help; but it cannot be our duty to make others happy, since this does not depend on us, and since it would only too often mean intruding on the privacy of those towards whom we have such amiable intentions.
Popper, Karl. The Open Society and Its Enemies. 1945.

There is no history of mankind, there is only an indefinite number of histories of all kinds of aspects of human life. And one of these is the history of political power. This is elevated into the history of the world. But this, I hold, is an offence against every decent conception of mankind. It is hardly better than to treat the history of embezzlement or of robbery or of poisoning as the history of mankind. For the history of power politics is nothing but the history of international crime and mass murder (including it is true, some of the attempts to suppress them). This history is taught in schools, and some of the greatest criminals are extolled as heroes.
Popper, Karl. The Open Society and Its Enemies. 1945.

...no matter how many instances of white swans we may have observed, this does not justify the conclusion that all swans are white.
Popper, Karl. The Logic of Scientific Discovery. 1934.

A principle of induction would be a statement with the help of which we could put inductive inferences into a logically acceptable form.
Popper, Karl. The Logic of Scientific Discovery. 1934.

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.
Popper, Karl. The Logic of Scientific Discovery. 1934.