Page - 188 - in The Priority of Locomotion in Aristotle’s Physics

all (see 7.2.2). Next, I will examine the claim from sentence (1) that of all kinds of change, locomotion, if undergone by x, changes x in essence the least. I will argue that making sense of the argument presupposes distin- guishing between ‘x undergoing a change in being’ and ‘x undergoing a change in essence’—a distinction that is essential for this argument (see 7.2.3). After this I will suggest that alteration and change in quantity, in contrast to locomotion, seem to involve their subject’s departing from its essence, as both may serve as necessary parts of certain substantial changes (7.2.4). As this proposal will turn out to be problematic, I will argue that the true reason for the asserted difference between locomotion and the other kinds of non-substantial change is that the latter in principle may, but do not have to, result in a change in essence of their subject, and that locomo- tion in this sense is indeed special (7.2.5). My last step will be to argue that it is because of this special feature that locomotion is the only change eter- nal things can undergo, and that this is the reason for its priority in essence with respect to such beings. Thereby, I will explain in what way the fifth argument as a whole supports Aristotle’s claim that only locomotion can be the change which is directly caused by the first unmoved mover (see 7.3). 7.2.2 Locomotion does not change its subject’s being What does Aristotle mean by the claim that locomotion, in contrast to the other two kinds of non-substantial change, does not change anything of its subject’s being (οὐδὲν μεταβάλλει τοῦ εἶναι)?49 From what Aristotle says in sentence (2) it is clear that he certainly does not intend to say that change in quality and in quantity change their sub- ject’s being in the sense that they change what the subject is, i.e. its essence, while locomotion does not. According to what is stated here, a change in either quantity or quality counts as a change τοῦ εἶναι. This means that εἶναι here does not stand for what is usually referred to by terms like ‘essence’ or ‘substance’ (οὐσία). A mere change in quality or quantity is not a change in essence. Change in quality and in quantity are explicitly defined by Aristotle as non-substantial changes; saying that every change in quality and quantity is a change in essence of the respective subject, as sentence (2) would if εἶναι stood for οὐσία, would contradict this basic assumption of the Aristotelian theory of change. In fact, the distinction drawn between substantial and non-substantial changes would be made obsolete. Thus, the 49 In what follows I will call the kind of change in which the subject is changed in being (τοῦ εἶναι) and about which Aristotle talks in l. 261a22 ‘change in being’. As I will show, this is to be distinguished from the case in which x departs from its essence (τῆς οὐσίας ἐξίστα- ται). 188 Locomotion is prior in essence ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen