Karl R Popper - Collected Quotes

“There is no such thing as a logical method of having new ideas or a logical reconstruction of this process […] very discovery contains an ‘irrational element’ or a ‘creative intuition’.” (Karl R Popper, “The logic of scientific discovery”, 1934)

“It is sometimes said of two expositions of one and the same mathematical proof that the one is simpler or more elegant than the other. This is a distinction which has little interest from the point of view of the theory of knowledge; it does not fall within the province of logic, but merely indicates a preference of an aesthetic or pragmatic character.” (Karl R Popper, “The Logic of Scientific Discovery”, 1934)

"Science is not a system of certain, or -established, statements; nor is it a system which steadily advances towards a state of finality […] And our guesses are guided by the unscientific, the metaphysical (though biologically explicable) faith in laws, in regularities which we can uncover - discover. Like Bacon, we might describe our own contemporary science - 'the method of reasoning which men now ordinarily apply to nature' - as consisting of 'anticipations, rash and premature' and as 'prejudices'." (Karl R Popper, "The Logic of Scientific Discovery", 1934)

“It is his intuition, his mystical insight into the nature of things, rather than his reasoning which makes a great scientist.” (Karl R Popper, “The Open Society and Its Enemies”, 1945)  

“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 R Popper, “Conjectures and Refutations: The Growth of Scientific Knowledge”, 1963)

“Classical models tell us more than we at first can know.” (Karl R Popper)

“A theory is just a mathematical model to describe the observations.” (Karl R Popper)

"Science starts from problems, and not from observations." (Karl R Popper)