Thinker · TH-0258
Karl Popper
Karl Popper was an Austrian-born British philosopher who taught in Christchurch, New Zealand, and then at the London School of Economics. In Logik der…
Also known as Sir Karl Raimund Popper
1902 – 1994 · Vienna; Christchurch, New Zealand; London
Traditions: Analytic
Karl Popper was an Austrian-born British philosopher who taught in Christchurch, New Zealand, and then at the London School of Economics. In Logik der Forschung (1934) he argued that science advances by bold conjectures and attempted refutations, not by induction, and that a theory is scientific only if it forbids something and could be falsified. He applied the same critical rationalism to politics, defending open societies against historicist theories. His account of risky prediction remains influential.
Key ideas
- A theory is scientific if it is falsifiable: it rules out possible observations.
- Science grows by conjectures and refutations; no amount of confirmation proves a universal theory.
- The problem of induction is avoided by treating theories as tested, corroborated guesses rather than verified truths.
- Societies should be open to criticism and reform piecemeal, rejecting claims to know the laws of history.
Major works
- Logik der Forschung (1934; The Logic of Scientific Discovery, 1959)
- The Open Society and Its Enemies (1945)
- The Poverty of Historicism (1957)
- Conjectures and Refutations (1963)
In the conversation
- Question My son says you can’t prove fairies don’t exist. Why is that a weakness, not a strength?
- Discussion How should a journalist judge a study in a field she knows nothing about?
- Debate Saving a theory with an auxiliary hypothesis is often exactly the right move
- Question Is negative utilitarianism the most compassionate moral theory, or the most dangerous one?
- Debate Lakatos found the right middle path between Popper and Kuhn
- Question What did Weber actually mean by “value-free” social science?
- Discussion Al-Fārābī’s virtuous city looks different on a bad day in a bookshop
- Reading group Reading group: Feyerabend’s Against Method, with the Galileo chapters at the centre
In the Journal
In the Coordinates
The questions of philosophy where Karl Popper takes a place, from The Coordinates of Thought.
- 6.8 Philosophy of Science What makes a claim scientific?
- 6.8.3 Scientific Revolutions Does science build on what came before, or replace it?