Seite - 116 - in The Priority of Locomotion in Aristotle’s Physics

types of change, but not vice versa1: since every change in the cosmos depends on this first eternal change, while it itself does not presuppose the occurrence of any other change, there is an asymmetric relation of ontologi- cal dependency between this primary change of place and all other kinds. And this, in addition to what was presented in the first two arguments, is another sense in which locomotion has ontological priority. Accordingly, the argument implies that whenever there is any change, one needs to pre- suppose the occurrence of locomotion, while there being locomotion in no way entails the occurrence of some other change. The way in which the argument is presented, however, is not straightfor- ward and at first glance it is not easy to distinguish the different steps that Aristotle makes from one to another in his argumentation. The passage begins by stating one of the two main premises of the argument, namely that “change must exist continuously”. What Aristotle certainly means by this is that change must exist without intermittence, that is, it must be eter- nal.2 This clearly is a reference to the claim for which Aristotle argued in the first two chapters of Book VIII of the Physics. There it was shown that if there is change in the cosmos in the way we observe it, then change has always existed and will always exist, i.e., is eternal.3 The first of the two main premises on which the third argument for the priority of locomotion relies then is that change exists eternally. As I will show, Aristotle rightly assumes that the everlasting change clearly needs to be one single change and cannot be a composite of more or less independent changes, since it is directly caused by the first unmoved mover, which is characterised as caus- ing a change that is one in a special sense and eternal. This is where loco- motion comes into play, for, as Aristotle claims in the second main premise of the argument, this eternal change “can be no other [change] than loco- motion.”4 From these two premises Aristotle then draws the conclusion that locomotion must therefore be primary.5 Consequently, in this argument locomotion’s primacy, contrary to what one might think at first glance, does not derive from the fact that locomotion alone can be the one eternal change that is caused directly by the first unmoved mover, but according to 1 A more general definition of ontological priority, as I shall show later on, will be that x is prior to y in this way, if and only if there is y there also must be x, but not vice versa. See 5.4.1 for more on this. 2 This also seems to be what most of the commentators think. See Philoponus, In Phys. 8, 897, 17–18, Simplicius, In Phys. 8, 1269, 17–18, Aquinas, In Phys., L. VIII, l.XIV, 1091, and Wagner (1967), 689. 3 See for instance Phys. VIII 1, 252b5–6. 4 ταύτην οὐδεμίαν ἄλλην οἷόν τε εἶναι ἀλλ᾽ ἢ φοράν, Phys. VIII 7, 260b25. 5 ἀνάγκη τὴν φορὰν εἶναι πρώτην. Phys. VIII 7, 260b25–26: “locomotion must be pri- mary.” 116 All changes depend on the first locomotion, but not vice versa ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen