A paradigm shift is a fundamental change in the basic concepts, methods, and assumptions underlying a scientific discipline or, by extension, any structured domain of inquiry or belief. The term was introduced by philosopher and historian of science Thomas S. Kuhn in his 1962 work The Structure of Scientific Revolutions, where he argued that science does not progress by simple accumulation of knowledge but through periodic, discontinuous revolutions in which one dominant framework - a “paradigm” - is replaced by another. The concept has since been adopted widely outside the philosophy of science, including in technology, business, culture, and social theory.

Kuhn observed that scientific communities operate within paradigms: shared assumptions, exemplary problems, methods, and standards that define what counts as legitimate inquiry. During periods of “normal science,” researchers work within the paradigm, solving puzzles it generates. When anomalies accumulate that the paradigm cannot explain, a crisis period follows, eventually resolved by the adoption of a new paradigm. Kuhn described this transition as a paradigm shift. He held that competing paradigms are, to a significant degree, “incommensurable” - meaning their core concepts and standards of evaluation are not fully translatable between frameworks.

The Copernican Revolution - the displacement of geocentric astronomy by the heliocentric model - is the canonical historical example Kuhn used to illustrate the concept. Other commonly cited examples include the transition from Newtonian mechanics to Einsteinian relativity and the acceptance of plate tectonics in geology.

The paradigm shift concept has been applied well beyond its original scientific context. In technology and business, the term is used to describe transformative changes in dominant methods or market structures - such as the shift from analog to digital media, or from mainframe computing to personal computers. In social and political theory, it has been applied to changes in prevailing frameworks of governance, moral philosophy, and cultural norms. Critics of this broader usage argue that it dilutes the term's original meaning and strips it of its specific epistemological content.

Several core claims in Kuhn's framework remain contested among philosophers and historians of science. The incommensurability thesis - the degree to which competing paradigms truly cannot be evaluated against shared rational standards - is disputed. Some philosophers, including Imre Lakatos and Karl Popper, offered alternative accounts of scientific change that preserve a stronger role for rational continuity and falsification. Paul Feyerabend extended Kuhn's insights in a more radical direction, arguing that no universal methodological rules govern science at all. Whether paradigm shifts are best understood as rational or sociological events - driven by evidence and argument, or by generational turnover and community dynamics - remains an open question in the philosophy of science.

There is broad agreement among historians and philosophers of science that scientific change involves both incremental and discontinuous elements, and that Kuhn's account captured genuine features of scientific practice that earlier cumulative models had missed. Whether Kuhn's specific theses about incommensurability and the sociology of scientific revolutions are correct remains debated. See the Philosophy of Science Consensus page for further detail.

• Kuhnian discontinuity - Scientific progress is fundamentally revolutionary rather than cumulative; paradigms are incommensurable and shifts are not straightforwardly rational events. See viewpoint.
• Popperian falsificationism - Scientific progress is better explained by conjectures and refutations; the discontinuity Kuhn describes does not undermine the rational evaluation of theories. See viewpoint.
• Lakatosian research programmes - Scientific change occurs through competing research programmes with hard cores and protective belts; neither pure accumulation nor Kuhnian revolution fully captures the dynamic. See viewpoint.
• Feyerabendian anarchism - No single method governs science; paradigm shifts illustrate that “anything goes” in scientific practice. See viewpoint.
• Sociological / constructivist - Paradigm shifts are primarily social phenomena shaped by power, community dynamics, and institutional forces rather than by epistemic criteria alone. See viewpoint.

• Paradigm Shift - History
• Paradigm Shift - Debate
• Philosophy of Science Consensus
• Copernican Revolution
• Philosophy of Science
• Scientific Revolution
• Normal Science
• Incommensurability
• Falsificationism

1. Kuhn, Thomas S. The Structure of Scientific Revolutions. University of Chicago Press, 1962.
2. Lakatos, Imre. “Falsification and the Methodology of Scientific Research Programmes.” In Criticism and the Growth of Knowledge, edited by Lakatos and Musgrave. Cambridge University Press, 1970.
3. Popper, Karl. The Logic of Scientific Discovery. Hutchinson, 1959.
4. Feyerabend, Paul. Against Method. New Left Books, 1975.
5. Bird, Alexander. “Thomas Kuhn.” Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/thomas-kuhn/