In September 1927, in observance of the centennial of Volta's death and the scientific pretensions of the Fascist state, the world's leading physicists gathered in Como, Italy. Among the speakers they heard was Niels Bohr, who said in his almost inaudible manner that the quantum mechanics built in the previous few years announced a revolution in human thought.¹ He called his version of the revolution "complementarity." Known now as the Copenhagen interpretation, it spread quickly among physicists, most of whom accepted it without troubling to understand it, and among philosophers attracted by the subject and by invigorating disputes between Bohr and Einstein about the foundations of physics. Excellent and comprehensive analyses of the technical points at issue have been given by historians and philosophers.²