Page - 123 - in The Priority of Locomotion in Aristotle’s Physics

Suppose, for instance, I were to set up lines of dominos standing on their ends, and after finishing such an arrangement, I were to push the first tile so that it knocks over the second, which topples the third, and so forth until all of the tiles have fallen. Each case of a toppling domino, of course, is a single change. But could one not also say that the process of one tile falling after another basically forms one single and continuous change in some way, if executed in a perfectly uniform manner? And if this really were the case, could we not go one step further and modify the thought experiment in such a way that an eternal change will be the outcome? For, suppose I were to make a line of tiles along a circular path, and that I were somehow able to stand each fallen tile on its end right after it falls (for example by using a robot or a special kind of machine). Once I start the process it could go on for ever, provided nothing is changed in the arrangement. In this way it seems that a change that may be thought of as one by being composed of a number of other changes would be eternal (at least in one direction). As we will see, Aristotle would deny that the first example is one continu- ous change and hence that the same applies to the second example. The rea- sons for this are stated in Phys. V 4, where Aristotle discusses different ways in which a change may have oneness or unity. Since the third argument for locomotion’s primacy is obviously based on the claim that a succession of changes that occur one after another cannot result in one continuous change, we should understand what the basic criteria are for saying that such changes taken as a whole cannot be one and continuous, and, there- fore, why the second option for explaining that change is eternal may be ruled out. Aristotle obviously presupposes that the reader is acquainted with the account of unity and oneness of change that is presented in Phys. V 4 and of which the current discussion clearly makes use to a certain extent. In what follows, I will therefore present parts of this account insofar as they are of importance for understanding the argument. 5.2.3 The criteria for being one continuous change In Phys. V 4 Aristotle presents different ways in which a change may be said to be one.21 For the purposes of our discussion only one of these kinds, namely being one without qualification (ἁπλῶς) is of importance, since as we will see this is the kind of unity that is specific to the change which is 21 In Phys. V 4 five ways in which a change may be called one (μία κίνησις) are pre- sented: being one (1) in genus (γένει), (2) in genus and species (γένει καὶ εἴδει), (3) without qualification (ἁπλῶς), (4) by being regular (ὁμαλῆς), and (5) by being complete (τέλειος). All five of them are of importance in the discussion of Phys. VIII 7–9. The unity of the eternal change 123 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen