Page - 177 - in The Priority of Locomotion in Aristotle’s Physics

than that locomotion has priority over the other kinds of change. But it is the latter which Aristotle intends to show in Physics VIII 7. The thought behind Aristotle’s argument seems to be the following: in living things each of the non-substantial kinds of change corresponds to and is caused by a certain capacity or part of the animal’s soul. If the capa- city to change in place is prior in essence to the animal’s capacity to change in quality and in quantity, then (in some way) locomotion itself is prior in essence to the two remaining non-substantial kinds of change. Because of this, Aristotle does not compare all of the different kinds of change that a living thing may undergo in general, but only those of which the source (ἀρχή) in some way lies in the living being itself and that thus is responsible for it in some sense.28 This is also the reason why Aristotle only has the non-substantial kinds of change in mind here: my inner principle of change and rest certainly was not responsible for my coming to be. From what Aristotle says in the De Anima it is clear that change in quan- tity is caused by the nutritive part of the soul (θρεπτικόν)29 and change in place by the locomotive part (κινητικόν).30 Aristotle, however, does not say in the De Anima which of the different capacities or parts of the soul is responsible for causing a change in quality that occurs in the animal. One might think that the sensory part (αἰσθητικόν) does so, as it is responsible for perception insofar as the soul is a cause (ἀρχή) of this sensory activity. But there are no doubt other occurrences of alteration in a living thing besides perception that originate from its soul and that are not merely changes undergone passively, for instance the case in which my skin becomes darker after I take a sunbath. Thus, saying that the sensory part is 28 I do not want to claim here that a living being is responsible in the same way for all the different changes that its soul is a cause of and which it undergoes not merely passively. Yet, one may say that these changes are on a par insofar as the living thing’s soul is their source or origin (ἀρχή) in some sense. For this is what distinguishes things that are by nature (φύσει) from such that are not: as Phys. II 1, 192b13–15, claims, the former have the source of their changes within themselves, be it a change in quality, quantity, or place. These are the kinds of change which are of relevance to the argument in question. The fact that an animal’s locomo- tion has an exceptional status, since in some sense it is the only kind of change in the animal that may be called self-motion in the appropriate sense, is of no importance here (see section 3.5, esp. p.62, where I refer to the relevant passage in Phys. VIII 2 and 6). On a discussion of the latter see Morison (2004). 29 The nutritive capacity is responsible, among other things, for taking in and transform- ing nourishment and assimilating it to the body so that the living being grows. See de An. II 4, 415a22–26 and 415b26–27, and also de An. III 9, 432b8–11. 30 In de An. II 2, 413b11–13, Aristotle states that the soul is the origin (ἀρχή) of and defined by various activities, one of them being locomotion (κινήσις). Later in II 3, 414a31– 32, when he enumerates the soul’s capacities he explicitly speaks of this capacity as κινητικόν κατὰ τόπον. Locomotion is prior in essence, since it is last in coming to be 177 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen