Philosophers / Karl Popper
Contemporary

Karl Popper

1902 – 1994
Vienna, Austria → London, England
Analytic Philosophy Philosophy of science Epistemology Political philosophy Logic

Karl Popper was an Austrian-British philosopher of science and political theorist whose concept of falsifiability revolutionized the philosophy of science and whose defense of the 'open society' against totalitarianism made him one of the most influential liberal thinkers of the 20th century. His argument that scientific theories can never be verified but only falsified, and that the growth of knowledge proceeds through bold conjectures and rigorous attempts at refutation, replaced the inductivist picture of science with a critical rationalist alternative.

Key Ideas

Falsifiability, critical rationalism, open society, three worlds, historicism critique

Key Contributions

  • Developed falsificationism: scientific theories cannot be verified but can be falsified — a theory is scientific if and only if it is in principle refutable
  • Replaced induction with the method of conjectures and refutations as the logic of scientific discovery
  • Defended the 'open society' against totalitarianism, tracing the intellectual roots of authoritarianism to Plato, Hegel, and Marx
  • Developed the concept of verisimilitude (truthlikeness) — the idea that science progresses by producing theories that are increasingly close to the truth
  • Argued against historicism — the doctrine that history follows inevitable laws or patterns

Core Questions

What distinguishes science from non-science (the demarcation problem)?
Can scientific theories ever be verified, or can they only be falsified?
How does scientific knowledge grow — through induction from observations, or through conjectures and refutations?
What political institutions best protect freedom and allow for the correction of errors?

Key Claims

  • A theory is scientific if and only if it is falsifiable — if there are possible observations that would refute it
  • Science does not proceed by induction (generalizing from observations) but by conjectures and refutations — bold hypotheses subjected to rigorous testing
  • We can never verify a universal scientific theory — a single counterexample suffices to refute it (asymmetry of verification and falsification)
  • The open society is one that permits criticism, reform, and the correction of errors without violence — closed societies suppress criticism
  • Historicism — the belief in inevitable historical laws — is intellectually bankrupt and politically dangerous

Biography

Life

Karl Raimund Popper was born on July 28, 1902, in Vienna. He studied philosophy and physics, and was associated with (but critical of) the Vienna Circle of logical positivists. His Logic of Scientific Discovery (1934) challenged the positivists' verification principle with his falsificationist alternative.

Popper fled to New Zealand in 1937, where he wrote The Open Society and Its Enemies (1945) — a passionate defense of liberal democracy against the totalitarian philosophies he traced to Plato, Hegel, and Marx. He moved to the London School of Economics in 1946, where he taught for the rest of his career. He was knighted in 1965 and died on September 17, 1994.

Legacy

Popper's falsificationism remains central to the philosophy of science, though it has been refined and criticized by Kuhn, Lakatos, and Feyerabend. His political philosophy continues to inspire defenders of liberal democracy.

Methods

Falsificationism (testing theories by attempting to refute them) Critical rationalism Conjectures and refutations Analysis of the logic of scientific discovery Critique of historicism and utopianism

Notable Quotes

"{'text': 'Those who promise us paradise on earth never produced anything but a hell.', 'source': 'The Open Society and Its Enemies, Chapter 9', 'year': 1945}"
"{'text': 'Science must begin with myths, and with the criticism of myths.', 'source': 'Conjectures and Refutations, Chapter 1', 'year': 1963}"
"{'text': 'Our knowledge can only be finite, while our ignorance must necessarily be infinite.', 'source': 'Conjectures and Refutations', 'year': 1963}"
"{'text': 'No rational argument will have a rational effect on a man who does not want to adopt a rational attitude.', 'source': 'The Open Society and Its Enemies', 'year': 1945}"

Major Works

  • The Logic of Scientific Discovery Treatise (1934)
  • The Open Society and Its Enemies Treatise (1945)
  • The Poverty of Historicism Treatise (1957)
  • Conjectures and Refutations Essay (1963)

Influenced

Influenced by

Sources

  • The Logic of Scientific Discovery (Routledge Classics)
  • Popper by Bryan Magee (Fontana Modern Masters)
  • The Cambridge Companion to Popper (ed. Jeremy Shearmur and Geoffrey Stokes)

External Links

Translations

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