Page - 216 - in The Priority of Locomotion in Aristotle’s Physics

the most fundamental change, does not suffice to fully explain how it is that the primary change is locomotion—especially if one bears in mind that, as we have seen, there are further possible objections against this claim, but also that one needs to spell out in what way this claim fits with other Aristo- telian assumptions about the cosmos as for instance the one that eternal things like the heavenly bodies may only change in a special way. As I have pointed out, one of the aforementioned objections is discussed in the fourth argument, which showed that the fact that locomotion with respect to the development of certain living beings is temporally posterior to the other three kinds of change fits very well with the priority claim. Yet, apart from that, the fourth argument first of all made clear that locomotion is prior to the other kinds of change in the sense which, as Aristotle points out in Cat. 12, is the most fundamental sense of priority, namely temporal priority.4 This must be shown to be true, for one is right to expect that the first unmoved mover and the motion he causes directly is prior to the other types of change in the temporal sense as well. Or to put it the other way around, if locomotion did not have temporal priority over the other kinds of change in the stated sense, then it could not possibly be the change that is caused by the first unmoved mover, because this change must precede all other changes in time, which is also why it is essential for Aristotle to find a satisfying answer to the aforementioned objection. With respect to the goal of presenting a full and consistent theory that as a whole makes it plausible that locomotion alone can be the change which the first unmoved mover imparts, the most important and powerful of the five arguments certainly is the fifth one; it not only makes clear that loco- motion in general has essential priority in all things that (apart from the unmoved mover) are responsible for the causation of change in the uni- verse, and that locomotion thus plays an extraordinary role in this context, but at the same time shows that change in place, due to its special nature, is the perfect (and indeed only) candidate for being the one eternal change that the outermost heavenly sphere undergoes, and that is directly caused to move by the first unmoved mover. For, again, of the four different kinds of change, locomotion alone leaves its subject’s essence completely untouched. This makes it possible that the outermost sphere and the other heavenly bodies, which in virtue of being eternal cannot change with respect to their being or essence in any way whatsoever, nonetheless may change in the manner necessary for there to be change in the cosmos in the way we experience it day by day and even to do so eternally, namely by undergoing the type of change that, although being the most fundamental 4 In Cat. 12, 14a26–27, Aristotle states that of the different senses of priority, something x is called prior to y in the most important sense with respect to time (πρῶτον μὲν καὶ κυριώ- τατα κατὰ χρόνον). 216 Conclusion ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen