Seite - 86 - in The Priority of Locomotion in Aristotle’s Physics

Yet, although this is not explicitly mentioned by any of the commenta- tors of Phys. VIII, there nonetheless seems to be a way, one might think, in which Aristotle’s claim that change in quantity in a sense necessarily involves change in place is problematic and might even contradict basic assumptions of Aristotle’s theory of change, especially the one which I will call the principle of irreducibility of the kinds of change. But if the fact that change in quantity in a certain sense can be considered as change in place really might contradict this basic Aristotelian principle, then this problem surely needs to be addressed. The principle of irreducibility says that there are exactly four different kinds of change that are on a par and that cannot be reduced to each other. These four kinds of change, as we know, are change in quality, quantity, place and substance, and, as is stated for instance in Phys. III 1, derive their existence from “the categories of that which is”31, that is, are more than just arbitrary names for certain phenom- ena. But if this is true one has to explain in what way it does not contradict the principle of irreducibility that growth and diminution are changes in place as Aristotle explicitly says in Phys. IV 4 and GC I 5. Part of the answer has already been given in my discussion above: change in quantity is not locomotion in the proper sense, as its subject changes in place only with respect to certain parts. However, the problem is not yet solved, but only shifted to another level. For the fact that what grows or diminishes merely changes in place with respect to its parts does not preclude the possibility that this change may be reduced—for instance by a Presocratic philosopher —to the movements of certain material parts, for example elements or atoms.32 First of all, Aristotle would—as he does in many places—reject the idea of the existence of indivisible constituents like atoms. But this argument would not suffice to reject this view in general. For the proponent of such a view, let us call him a reductionist, would agree to many of the things said so far. He of course would say that what changes in quantity changes in place. He would also agree with the Aristotelian assumption that if some- and diminution obviously is a “Zusatznotiz” without giving any reason for his assumption. By contrast, Wagner (1967), 688, who at least admits that change in quantity is sometimes considered as change in place by Aristotle, does not state in what way the section on change in quantity does not fit into Aristotle’s theory. Graham (1999) completely ignores the whole section on change in place and mentions it neither in his commentary (122–123) nor in his reconstruction of the argument presented in the appendix (187). 31 τῶν τοῦ ὄντος κατηγοριῶν, Phys. III 1, 200b28. For the whole context see 200b26– 201a9. Something similar is said in Phys. V 2 in which the different kinds of κίνησις are also derived from the different categories. 32 I would like to thank Caleb Cohoe for pointing this out to me. 86 Locomotion necessarily accompanies each of the other kinds of change ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen