 One of Kepler’s decisive innovations in his MC is that he replaced the “mean Sun” of Copernicus with the real Sun, which was no longer merely a geometrical point but a body capable of physically influencing the surrounding planets. In addition, in notes to the 1621 edition of MC Kepler strongly criticizes the notion of “soul” (anima) as a dynamical factor in planetary motion and proposes to substitute “force” (vis) for it (see KGW 8, p. 113, Engl. trans. p. 203, note 3).