 That said, when Leibniz discusses the relativity of motion – which he calls the ‘equivalence of hypotheses’ about the states of motion of bodies – some of his statements do suggest that he was confused in this way. For another way of stating the problem for the folk reading is that the claim that relative motions alone suffice for mechanics and that all relative motions are on a par is a principle of general relativity, and could Leibniz – a mathematical genius – really have failed to notice that his laws hold only in special frames? Well, just maybe. On the one hand, when he explicitly articulates the principle of the equivalence of hypotheses (for instance in Specimen of Dynamics) he tends to say only that one cannot assign initial velocities on the basis of the outcome of a collision, which requires only Galilean relativity. However, he confusingly also claimed (On Copernicanism and the Relativity of Motion, also in Garber and Ariew 1989) that the Tychonic and Copernican hypotheses were equivalent. But if the Earth orbits the Sun in an inertial frame (Copernicus), then there is no inertial frame according to which the Sun orbits the Earth (Tycho Brahe), and vice versa: these hypotheses are simply not Galilean equivalent (something else Leibniz could hardly have failed to realize). So there is some textual support for Leibniz endorsing general relativity for the phenomena, as the folk reading maintains.