Philosopher
Karl Popper
1902–1994
Also known as Sir Karl Popper, Karl Raimund Popper
Philosopher of science who made falsifiability the mark of a scientific theory, and a political philosopher who defended the 'open society' against totalitarianism.
The fact that we predict eclipses does not, therefore, provide a valid reason for expecting that we can predict revolutions.
Popper was born in Vienna in 1902 to parents of Jewish origin. As a young man he was briefly a Marxist, worked with deprived children in one of Alfred Adler’s clinics, trained as a cabinetmaker and heard Einstein lecture. He was struck by the contrast: Einstein’s theory made predictions that could have proved it false, while Marxism and psychoanalysis seemed confirmed by everything. He took a doctorate in psychology in 1928 and qualified as a schoolteacher.
From 1937 he taught in New Zealand, at the University of Canterbury, staying there through the war; the annexation of Austria spurred him to write The Open Society and Its Enemies there. From 1946 he taught at the London School of Economics, where his students included Imre Lakatos and Paul Feyerabend. He was knighted in 1965 and died in 1994. Combative and often isolated among British philosophers, whose fixation on language he blamed on Wittgenstein, he is widely counted among the twentieth century’s greatest philosophers of science.
Key ideas
- Falsifiability
- No number of observations can verify a universal law, but a single genuine counter-instance refutes it. A theory is scientific only if it makes risky predictions that could turn out false; theories that explain everything, like the psychoanalysis Popper met in Vienna, are not testable.
- No induction
- Popper accepted Hume’s critique of induction and went further, arguing that science never uses it. All observation is selective and “theory-laden”; there are no pure facts from which theories could be built up.
- Conjectures and refutations
- Knowledge grows from problems. Scientists propose bold conjectures, a leap of creative imagination, and then test them deductively, keeping those that survive until they are refuted.
- Against historicism
- History does not unfold by necessary laws towards a determinate end, as Marxism claimed. Predicting eclipses gives no reason to think we can predict revolutions.
- The open society
- Instead of remaking society to a blueprint, we should use “piecemeal social engineering”, pursuing one goal at a time so that unintended harms can be seen and corrected, in the same critical spirit as science.
- Tradition
- Western
- Region
- Austria, New Zealand and England
- Period
- Contemporary
Influences
Influenced by
Karl Popper1902–1994
Influenced
Influenced by
Karl Popper1902–1994
Influenced
Where these links come from
- Karl Popper drew on David Hume. Source: Stephen Thornton, Karl Popper, Stanford Encyclopedia of Philosophy
- Karl Popper argued against Karl Marx. Source: Stephen Thornton, Karl Popper, Stanford Encyclopedia of Philosophy
- Thomas Kuhn argued against Karl Popper. Source: Alexander Bird, Thomas Kuhn, Stanford Encyclopedia of Philosophy
Key works
- The Logic of Scientific Discovery (Logik der Forschung), 1935
- The Open Society and Its Enemies, 1945
- The Poverty of Historicism, 1957
- Conjectures and Refutations, 1963
Sources
- Stephen Thornton, Karl Popper, Stanford Encyclopedia of Philosophy