The Structure of Scientific Revolutions

by Thomas S. Kuhn

Combined, relativity and quantum physics overthrew not only old science but basic metaphysics. Kant had taught that absolute Newtonian space and the principle of uniform causality are a priori principles of thought, necessary conditions on how human beings comprehend the world in which they live. Physics proved him totally mistaken. Cause and effect were mere appearance, and indeterminacy was at the root of reality. Revolution was the order of the scientific day. Before Kuhn, Karl Popper (1902–94) was the most influential philosopher of science—I mean the most widely read, and to some extent believed, by practicing scientists.16 Popper had come of age during the second quantum revolution. It taught him that science proceeds by conjectures and refutations, to use the title of one of his books. It was a moralistic methodology that Popper claimed was exemplified by the history of science. First we frame bold conjectures, as testable as possible, and inevitably find them wanting. They are refuted, and a new conjecture must be found that fits the facts. Hypotheses can count as “scientific” only if they are falsifiable. This purist vision of science would have been unthinkable before the great turn-of-the-century revolutions. Kuhn’s emphasis on revolutions can be seen as the next stage after Popper’s refutations. His own account of the relation between the two is “Logic of Discovery or Psychology of Research.”17 Both men took physics as their prototype for all the sciences and f...