Page - 52 - in The Priority of Locomotion in Aristotle’s Physics

which needs to be altered in order to be absorbed by the body, needs to be moved to the place where digestion occurs and there come in contact with a source of heat which turns the food from cold to hot so that it can be cooked and turned into blood. Yet, is it really necessary that alteration always involve a change in place? Suppose there is a case in which the contact that is necessary for alteration does not need to be established, since it is already the case that what will become an alterer later on and the future altered thing already are in con- tact and in fact always have been in contact. Accordingly, it appears, no locomotion would be necessary if one were to alter the other. For, when at some point one of the two things starts to impart heat to the other thing, which is cold, and by doing so alters the adjoining thing with which it is in contact, it seems that it is possible for a change from hot to cold to occur without locomotion. But this objection could be rejected in the following way. In the stated case the alterer itself must be hot in order to change the other thing from cold to hot. Either the alterer has always been hot, or it became hot at some point. In the first case there simply would be no alteration. For, if both things have always been in contact and the alterer has always been hot, then it would not make sense to say that the alteration starts at a specific point; rather, if this were the case, the other thing would also always have been hot itself (provided, of course, that what is supposed to be altered here is not affected suddenly by some other source of change.) In the case where the alterer becomes hot at some point in time, there must be some other alterer which is responsible for this change from hot to cold. But in order for that to take place the future alterer and what changes it from cold to hot also need to come in contact with each other first. Since every change needs to have a cause, this then would either lead to an infinite chain in which one thing alters the next, or to claiming that this change can be traced back to a first unmoved mover. As we know from the discussion in chapters 5 and 6 of Phys. VIII, Aristotle has very good reasons to reject the first and to favour the second option.34 That the first change, of which the unmoved mover is the direct cause and that must be eternal, cannot be alteration is shown by Aristotle in Phys. VIII 835; this, however, would be necessary for the aforementioned objection to work. Therefore, it is clear that the case stated above is not a real objection against the claim that any alteration pre- supposes the occurrence of a locomotion in virtue of the fact that the alterer and what is altered need to move together in order to touch each other. 34 See Phys. VIII 5, 256a4–21, and VIII 6, 259a6–20. 35 The reason in short is that alteration cannot be this first everlasting change, as it cannot be eternal; as a change between contraries it is limited and must come to a halt at some point. See Phys. VIII 7, 261a31–261b3. 52 Change in quality and quantity of living beings ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen