Page - 147 - in The Priority of Locomotion in Aristotle’s Physics

necessary for a number of reasons for changes undergone by eternal things, like for instance the primum mobile, which is directly caused to change by the first unmoved mover. As we have also seen, each of the other kinds of change, that is, change in quality, quantity, and substance can only be finite. Against this background then it is clear why the mere fact that eternal enti- ties only change with respect to their place shows, in Aristotle’s view, that locomotion in general must have priority in time. In the discussion in Phys. VIII 1–6 it was established that there must be at least one eternal change.7 In addition, the previous chapter of my discussion showed that this eternal change can only be locomotion. This eternal locomotion then will always be temporally prior to, i.e. earlier than, any other non-eternal type of change, because such a finite change needs to start at some point, and will always be preceded in time by the eternal locomotion of the heavenly spheres and bodies, which in virtue of being eternal may therefore be said to occur earlier than it. Given that this is the correct understanding of the first two lines8, it also follows that priority in time here is used in the sense in which it is intro- duced in Cat. 12 and Met. V 11.9 For x to be prior in time to y then merely means that x is earlier than y. In this way, for instance, the father of x is prior in time to x, since he existed earlier than x.10 The definition of temporal priority that underlies the fourth argument for locomotion’s priority accordingly would be the following: TEMPORAL PRIORITY: Of two changes x and y, x is temporally prior to y, iff there is a time prior to y at which x is occurring. 7 See for instance Phys. VIII 6, 259a13–20. 8 There is consensus among Themistius, Philoponus, Simplicius, Aquinas, Ross (1936), Wagner (1967), and Graham (1999) that this is the way in which the first two lines of the pas- sage and therefore the basic argument stated here need to be understood. 9 See Cat. 12, 4a26–29, and Met. V 11, 1018b14–19. In Met. V 11 as well, x being prior in time to y means that x is earlier than y, although Aristotle’s definition of temporal priority in terms of being closer or farther away from the now is of course not unproblematic. For more on the problematic definition see Kirwan (1993), 153. 10 Note that, as we will see later on, the fact that the eternal locomotion is prior to any occurrence of the three other kinds of change does not contradict the fact that this locomo- tion also succeeds each of these changes. Locomotion has priority in time 147 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen