And we have first to decide whether contrary motions are motions respectively from and to the same thing, eg a motion from health and a motion to health (where the opposition, it would seem, is of the same kind as that between coming to be and ceasing to be); or motions respectively from contraries, eg a motion from health and a motion from disease; or motions respectively to contraries, eg a motion to health and a motion to disease; or motions respectively from a contrary and to the opposite contrary,