Page - 185 - in The Priority of Locomotion in Aristotle’s Physics

The argument itself is sound. Yet, one has to keep in mind in what context it is stated. It is one of the two arguments by means of which Aristotle intends to show that locomotion, not the capacity to self-cause locomotion, is prior in essence. But it is also Aristotle’s answer to a possible objection against the priority claim. For, as we have seen in the discussion of the fourth argument, locomotion is the last of the different kinds of change (ὑστάτη τῶν κινήσεων), as it comes last to individual living things in their development.46 But this fact of the posteriority of locomotion seems to con- tradict the thesis that it is the primary kind of change, a thesis which is sup- posed to show that only locomotion can be the kind of change that has its primary source in and is directly caused by the first unmoved mover. Aristotle’s answer to this objection, as we have seen, is that locomotion is prior in another, more important sense of priority, not in spite of the fact that it is posterior in coming to be, but rather because it is posterior, which shows its primacy. As I have stated at the beginning of this chapter, it is important to keep in mind that in the greater context of Aristotle’s theory teleology plays an essential role. Changes occur for the sake of reaching cer- tain goals or ends; in the case of the coming to be of animals the goal is for them to reach their maturity, that is, to completely fulfil their form and essence. Explaining, and therefore knowing, why a change occurs and what its nature is, is only possible by making reference to its goal, which is why the ends of changes have explanatory priority. But for those perishable liv- ing things that at least potentially are able to move themselves it is more essential and specific to them that they be able to serve as the source of their own locomotion, than the source of other changes, especially since being the source of one’s locomotion implies that one also has the capacities, i.e. parts of the soul that are responsible for the other partly self-caused changes to occur. That is to say, having the capacity for locomotion contributes more to fulfilling a living thing’s form and nature, and to reaching the goal for the sake of which this whole process of coming to be takes place. This is the sense in which locomotion—in virtue of the locomotive capacity’s priority—is prior in essence and in nature, which, as I have shown, is not only claimed, but also shown by Aristotle in the first half of the fifth argu- ment. But Aristotle does more than merely deal once again with the stated objection against his claim of the primacy of locomotion and show the essential role that locomotion plays for perishable living things. For, in doing so he also presents very good reasons for assuming that this must be the kind of change which is directly caused by the first unmoved mover, which in Met. XII is identified with god. Showing that locomotion is pri- 46 See Phys. VIII 7, 260b30–33. Locomotion is prior in essence, since it is last in coming to be 185 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen