A view of the social structure of science is now popular, according to which each discipline of science is autonomous and its membership is divided into the few leaders and the rank-and-file, also known as normal scientists. The leaders declare what is the model scientific theory in the field, also known as a paradigm. A scientific revolution is a paradigm change, and is effected by the leadership, old or new. Normal scientists, finally, solve routine problems, also known as puzzles, in the light of the paradigm. This terminology is of Thomas S. Kuhn. The view it reflects is now popular, its advocate is Kuhn and its originator is Michael Polanyi.