Karl Popper Quotes

Liberalism is an attitude rather than a set of dogmas - an attitude that insists upon questioning all plausible and self-evident propositions, seeking not to reject them but to find out what evidence there is to support them rather than their possible alternatives.

I like the scientific spirit-the holding off, the being sure but not too sure, the willingness to surrender ideas when the evidence is against them: this is ultimately fine-it always keeps the way beyond open.

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.

The sooner we can separate salvageable skeptics from self-righteous absolutists, the sooner we can move along.

True science teaches, above all, to doubt and to be ignorant.

I think we ought always to entertain our opinions with some measure of doubt. I shouldn't wish people dogmatically to believe any philosophy, not even mine.

To have doubted one's own first principles is the mark of a civilized man.

[It is] ... a sound maxim that it is better only sometimes to be right than at all times to be wrong, so soon as I discover my opinions to be erroneous, I shall be ready to renounce them.

True science teaches, above all, to doubt

The great benefit of philosophy, which is also its great weakness, is that all its steps are taken in the spirit of doubt.

Science is a method, not a religion, yet it can be just as close-minded. Open minds here Claire. Always open minds. Question everything, accept nothing as fact until you prove it for yourself.

It will contribute towards one's object, who wishes to acquire a facility in the gaining of knowledge, to doubt judiciously.

The doubter is a true man of science: he doubts only himself and his interpretations, but he believes in science.

When you spring to an idea, and decide it is truth, without evidence, you blind yourself to other possibilities.

It's perfectly healthy-encouraged, even- to have an idea tomorrow that contradicted your idea today

Skepticism is not a position; skepticism is an approach to claims, in the same way that science is not a subject but a method.

Indeed the reasoned criticism of a prevailing belief is a service to the proponents of that belief; if they are incapable of defending it, they are well advised to abandon it. This self-questioning and error-correcting aspect of the scientific method is its most striking property.

Our belief is not a belief. Our principles are not a faith. We do not rely soley upon science and reason, because these are necessary rather than sufficient factors, but we distrust anything that contradicts science or outrages reason. We may differ on many things, but what we respect is free inquiry, openmindedness, and the pursuit of ideas for their own sake.

A skeptic as to all ideas, including especially my own, I have never suffered a pang when the ideas of some other imbecile prevailed.

I had begun to read books and things and, in fact, one of the persons who started me thinking seriously was an atheist that I, another negro inmate whom I'd heard in a discussion with white inmates and who was able to hold his own at all levels. And he impressed me with his knowledge, and I began to listen very carefully to some of the things he said.

Don't hold strong opinions about things you don't truly understand.

My own opinion is that belief is the death of intelligence. As soon as one believes a doctrine of any sort, or assumes certitude, one stops thinking about that aspect of existence.

Forbear to spew out reason from your mind, but rather ponder everything with keen judgment; and if it seems true, own yourself vanquished, but, if it is false, gird up your loins to fight.

The "passion for incredulity" can produce as much self-deception as the uncritical will to believe.

Critical thinking is to a liberal education as faith is to religion. ... the converse was true also - faith is to a liberal education as critical thinking is to religion, irrelevant and even damaging.