Conjectures and Refutations

Popper's collected essays argue that what separates genuine science from pseudoscience is not, as commonly assumed, whether a theory has amassed supporting evidence, since almost any theory can be made to look confirmed if its adherents look hard enough for confirming instances. The real test, Popper insists, is falsifiability: a theory earns scientific status only if it makes specific, risky predictions that could, in principle, be shown false by observation, and it earns credibility only by surviving serious, good-faith attempts at refutation rather than by attracting believers who explain away every apparent counterexample. He illustrates the contrast using Einstein's general relativity, whose predictions about starlight bending during a solar eclipse could have failed and would have doomed the theory, against Marxist history and psychoanalysis, which Popper argues had become so flexible in their explanatory reach that virtually no observation could ever count against them.

This matters because it reframes the entire logic of scientific progress: rather than theories being built up from observations through induction, which Popper considers philosophically indefensible, science advances through a Darwinian process of proposing bold conjectures and eliminating the ones that fail rigorous tests, with surviving theories remaining permanently provisional rather than proven true. The essays, written across decades and later gathered into this volume, apply this falsificationist framework to political theory, the philosophy of history, and the ethics of intellectual inquiry itself, arguing that a critical, self-questioning attitude is what separates open, rational inquiry from dogma.

Who should read it

Anyone interested in why some theories deserve to be called scientific and others don't, or in the ongoing debate over how science actually makes progress, will find Popper's central distinction genuinely clarifying, even where later philosophers have pushed back on parts of his account.

About the author

Karl Popper was an Austrian-British philosopher of science, widely regarded as one of the twentieth century's most influential thinkers on the logic of scientific discovery and on political and social philosophy.