Thomas Kuhn

Key ideas

In The Structure of Scientific Revolutions, Kuhn argued that most science is 'normal science': puzzle-solving within a shared framework, or paradigm, that defines which problems matter and what counts as a solution. Anomalies are usually set aside.

When anomalies pile up, a crisis can lead to a revolution, a paradigm shift, as when Copernican astronomy replaced the Ptolemaic system. Kuhn claimed that rival paradigms can be partly 'incommensurable': they use terms differently and value different things, so the choice between them is not settled by a neutral rule.

Critics took this to make science irrational; Kuhn denied that, but his work changed how philosophers think about progress and truth in science. It is one of the main positions in science and truth.

Life, briefly

Kuhn trained as a physicist at Harvard and turned to the history of science while teaching a course on it for non-scientists. He taught at Berkeley, Princeton and MIT. The Structure of Scientific Revolutions has sold over a million copies and is among the most cited academic books of the twentieth century.

Major works

• The Copernican Revolution (1957)
• The Structure of Scientific Revolutions (1962)
• The Essential Tension (1977)

Further reading

• EncyclopediaStanford Encyclopedia of Philosophy: Thomas Kuhn
• WikipediaThomas Kuhn