A paradigm shift is a fundamental conceptual transformation that accompanies a change in accepted theory within a scientific field. The term was introduced by the historian and philosopher of science Thomas S. Kuhn in his influential 1962 book, The Structure of Scientific Revolutions. Kuhn referred to the network of conceptual, theoretical, and methodological commitments shared by scientists in a given field as a paradigm. He argued that a significant change in accepted theory is accompanied by profound changes in this network of group commitments. The result is a fundamental transformation in the way scientists view the world and pursue their research. This entry explains the notions of paradigm and paradigm shift as Kuhn presented them.