Seite - 94 - in The Priority of Locomotion in Aristotle’s Physics

not mean that this is all that happens in a substantial change, nor that a change in substance is reducible to aggregation and segregation. This fact also has implications for the coming to be of all natural things in general. The four elements of earth, water, air, and fire, are the basic material constituents of all bodily things that exist in the sublunary sphere. This is why Aristotle thinks it necessary to inquire into what these elements are and what role they play, if one is to understand how generation and cor- ruption of substances occur, substances that are constituted by nature (ταῖς φύσει συνεστώσαις οὐσίαις) and thus have a body.54 For according to Aristotle—and here he basically agrees with his predecessors—it is a change in the elements, either an aggregation, or a segregation, or some other kind of change, that is at least partly responsible for the generation and corrup- tion of things.55 In other words, any generation or corruption of things that have a body necessarily involves σύγκρισις or διάκρισις of its basic mate- rial components, i.e. the elements. That this is Aristotle’s view becomes clear when he explicitly identifies the mixing of the elemental bodies, whereby these bodies perish in order to form homoeomeres like flesh and bone, with the process of aggregation.56 The dissolving of such a mixture accordingly needs to be understood as segregation. Thus, not only the changes of the elemental bodies, but also the substantial change which com- posite substances like plants and animals undergo always involves aggrega- tion and segregation insofar as the basic material components of these sub- stances do so. In this sense one may say that generation and corruption in general are processes of aggregation or segregation of the elements and occur in virtue of these processes. But generation and corruption, of course, cannot be reduced to these processes, which take place on the material level. The crucial point about substantial change is that it is a change with respect to the form of that which undergoes it. This is the reason why Aristotle emphasizes that gen- eration and corruption cannot be defined by σύγκρισις and διάκρισις.57 It is true that the occurrence of either of the latter two processes is a neces- sary condition for one of the former to take place, but the mere occurrence 54 See GC II 1, 328b31–33. For the fact that the four elemental bodies are the basic mate- rial constituents of substances with respect to their bodies see also, e.g. GC II 8, 334b31–32, and GA I 1, 715a8–11. 55 ἐξ ὧν μεταβαλλόντων ἢ κατὰ σύγκρισιν ἢ διάκρισιν ἢ κατ᾽ ἄλλην μεταβολλὴν συμβαίνει γένεσιν εἶναι καὶ φθοράν. GC II 1, 329a5–8. 56 In GC I 6, 322b8, Aristotle says explicitly that ἒστι δ᾽ ἡ σύγκρισις μίξις. This mixture of the elemental bodies, however, leads to the homoeomeres, which again serve as the matter of composite substances. For more on this see for instance Mete. IV 12, 389b24–29 and GA I 1, 715a8–11. 57 οὐχ ἡ ἁπλῆ καὶ τελεία γένεσις συγκρίσει καὶ διακρίσει ὥρισται, GC I 2, 317a17– 18. See p.92, n.43. 94 Locomotion necessarily accompanies each of the other kinds of change ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen