 The eight question (195v-201r) is whether, in order to compare two motions belonging to the same genus (of motion), it is necessary that the mover and the mobile be simultaneous. Sharpe’s answer is affirmative, but he specifies that it is not always possible to compare two motions belonging to the same genus. This is possible only when the motions that have to be compared belong to the same kind (species specialissima).