APA Dictionary of Psychology

a major change in the theoretical framework of a field of science, as identified by U.S. philosopher of science Thomas Kuhn (1922–1996). Research carried out within the framework of a normal science—that is, one with an active paradigm that defines the subject matter and methods of the science—will over time yield anomalies that are inconsistent with predicted results. When a sufficient number of anomalies occur, a crisis stage may emerge, which motivates scientists and theorists to rethink the fundamental assumptions and methods of the science, and a complete reformulation may take place. This drastically changes both the activities and perspective of the scientists involved and the nature and subject matter of the science, at which time a new normal science may emerge. See also paradigm clash; paradigm shift.