 Many readers were surprised not to find mention of paradigms or incommensurability. Kuhn later added an Afterword, “Revisiting Planck”, explaining that he had not repudiated or ignored those ideas but that they were implicit in the argument he gave. Indeed the whole essay may be seen as a demonstration of an incommensurability between the mature quantum theory and the early quantum theory of Planck which was still rooted in classical statistical physics. In particular the very term ‘quantum’ changed its meaning between its introduction by Planck and its later use. Kuhn argues that the modern quantum concept was introduced first not by Planck but by Einstein. Furthermore, this fact is hidden both by the continued use of the same term and by the same distortion of history that has affected our conception of Ptolemy and Copernicus. As in Copernicus’ case, Planck has been seen as more revolutionary than in fact he was. In Planck’s case, however, this misconception was also shared by Planck himself later in life.