Planck and the Special Theory of Relativity

Max Planck was considered to be among the most conservative figures in the history of physical science, because of his reluctance of accepting quantum mechanics (which he himself had helped to create) and his life-long effort to reconcile it with classical mechanics. Thus, it is something of a puzzle to see Planck as among the first physicists to embrace Einstein's special theory of relativity, equally revolutionary as quantum mechanics. The main burden of this paper is to find out why Planck so readily accepted and defended Einstein's theory. I suggest that Einstein's later criticism of certain interpretations of quantum mechanic may have its roots in Planck's skeptical attitude.