Thomas Samuel Kuhn (July 18, 1922 – June 17, 1996) was an American scholar who began his career in the physical sciences and became a leading figure in the history and philosophy of science. He is often described as a physicist and a historian and philosopher of science. Born in Cincinnati, Ohio, he spent much of his career examining how scientific ideas develop and interact with the communities that practice them. He died in Cambridge, Massachusetts, and his work continues to shape debates about scientific change.

Major contribution

Kuhn's best-known book, The Structure of Scientific Revolutions, introduced a new vocabulary for thinking about scientific practice. Rather than seeing science as a straightforward accumulation of facts, Kuhn argued that research typically happens within a prevailing framework or "paradigm." Normal science involves puzzle-solving within that framework; periodically the accumulation of anomalies leads to a crisis and, sometimes, to a revolutionary shift to a new paradigm.

Key concepts

  • Paradigm: a shared set of theories, methods, and exemplars that guide a scientific community.
  • Normal science: the routine research and problem-solving carried out under a paradigm.
  • Scientific revolution: a fundamental reorientation in which a new paradigm replaces an old one.
  • Incommensurability: the idea that competing paradigms can be difficult to compare using a single neutral standard.

Kuhn's framing shifted attention from isolated results to the social and conceptual structures that make scientific work possible. His view emphasized episodes of discontinuity and reinterpretation rather than linear progress.

Impact and reception

The term "paradigm shift" entered popular and scholarly language and influenced fields beyond philosophy—history, sociology, political science, and business studies all adopted his notions to explain large-scale change. At the same time, Kuhn attracted criticism: some accused him of promoting relativism or overstating the discontinuity between successive scientific frameworks. Kuhn responded to critics and refined aspects of his account in later editions and essays.

Today Kuhn's ideas remain central to discussions about how science evolves, how communities settle questions, and how revolutions in thought reshape knowledge and practice.