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.

— Karl Popper Conjectures and Refutations: The Growth of Scientific Knowledge (1963)

More quotes by Karl Popper

The Open Society and Its Enemies (1945)

The Open Society and Its Enemies (1945)

The Open Universe : An Argument for Indeterminism (1992)

Conjectures and Refutations: The Growth of Scientific Knowledge (1963)

In Search of a Better World (1984)

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