Karl Popper Quotes

The quest for precision is analogous to the quest for certainty and both - precision and certainty are impossible to attain.

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

The conspiracy theory of society... comes from abandoning god and then asking: "Who is in his place"

I have learned more from Hayek than from any other living thinker, except perhaps Alfred Tarski - but not even excepting Russell.

All things living are in search of a better world .

I am opposed to looking upon logic as a kind of game. ... One might think that it is a matter of choice or convention which logic one adopts. I disagree with this view.

Plato felt that a complete reconstruction of society's political program was needed.

The moral decisions of others should be treated with respect, as long as such decisions do not conflict with the principle of tolerance.

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

We hate the very idea that our own ideas may be mistaken, so we cling dogmatically to our conjectures.

No number of sightings of white swans can prove the theory that all swans are white. The sighting of just one black one may disprove it.

Better our hypotheses die for our errors than ourselves.

Simple statements are to be prized more highly than less simple ones because they tell us more; because their empirical content is greater; and because they are better testable.

Every genuine test of a theory is an attempt to falsify it, or to refute it.

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

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

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

It must be possible for an empirical system to be refuted by experience.

Definitions.... are never really needed, and rarely of any use

The defence of democracy must consist in making anti-democratic experiences too costly for those who try them; much more costly than a democratic compromise

The history of science, like the history of all human ideas, is a history of irresponsible dreams, of obstinacy, and of error.

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.

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.

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

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

What really makes science grow is new ideas, including false ideas.

Every discovery contains an irrational element or a creative intuition.

There is no history of mankind, there is only an indefinite number of histories of all kinds of aspects of human life.

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.

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

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

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

Our belief in any particular natural law cannot have a safer basis than our unsuccessful critical attempts to refute it.

Criticism of my alleged views was widespread and highly successful. I have yet to meet a criticism of my views.

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.

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

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

No particular theory may ever be regarded as absolutely certain.... No scientific theory is sacrosanct.

Serious rational criticism is so rare that it should be encouraged. Being too ready to defend oneself is more dangerous than being too ready to admit a mistake.

Our knowledge can only be finite while our ignorance must necessarily be infinite.

We must plan for freedom, and not only for security, if for no other reason than that only freedom can make security secure.