Seite - 92 - in The Priority of Locomotion in Aristotle’s Physics

defined in terms of these two processes.43 This seems to contradict what is stated in the passage from Phys. VIII 7—at least at first glance. In GC I 2, however, Aristotle also explicitly states that he nevertheless thinks that “aggregation and segregation exist” and occur in nature.44 Yet, Aristotle is careful to emphasize that his understanding of the processes of aggregation and segregation differs significantly from that of his predeces- sors. Crucially, Aristotle thinks it is wrong to say that what aggregates or segregates are indivisible particles like atoms, as some of the Presocratic thinkers claimed.45 In fact GC I 2 presents among other things arguments aimed at refuting these and other mistaken assumptions about aggregation and segregation. Yet, Aristotle does not really present examples of actual occurrences of processes he himself would call σύγκρισις and διάκρισις, but he does so in other places, for instance in the Meteorology. There he states that for example water vapour, of which clouds consist, is the segregation of water (ὕδατος διάκρισις) and tells us that clouds are dissolved by being segregated through the heat (διακρίνουσαι τῇ θερμότητι) originating from the sun.46 In another passage of the same work Aristotle explains that certain phenomena of light often appear in the night sky “when [air] becomes further aggregated” (ὅταν συγκριθῇ μᾶλ- λον).47 These and many other passages clearly indicate that Aristotle uses the concepts διάκρισις and σύγκρισις in order to account for certain pro- cesses that play an important role in nature.48 The passages quoted above also suggest that the two concepts are essen- tial for explaining how the four elemental bodies, i.e. earth, water, air, and fire, undergo generation and corruption. Aristotle argues that each of the four elements can turn into any of the other elements.49 If, for example, water is heated, it undergoes segregation and at some point perishes, so that air comes to be.50 These passages show that for Aristotle generation and 43 οὐχ ἡ ἁπλῆ καὶ τελεία γένεσις συγκρίσει καὶ διακρίσει ὥρισται, GC I 2, 317a17– 18. 44 ὥστ᾽ ἔστι καὶ διάκρισις καὶ σύγκρισις, GC I 2, 317a12–13. 45 This becomes clear for instance in the full context of the passage I just quoted in n.44, i.e. GC I 2, 317a12–17. There Aristotle states that aggregation and segregation exist “but not into and out of atoms” (ἀλλ᾽ οὐτ᾽ εἰς ἄτομα καὶ ἐξ ἀτόμων). 46 For the first example see Mete. I 3, 340b3: ἡ γὰρ ἀτμὶς ὕδατος διάκρισις ἐστιν; for the second see Mete. I 3, 340a29–30. 47 See Mete. I 5, 342b16–17. 48 For more examples see for instance Mete I 3, 340a8–10, 341a4, a9–10, and Mete I 4, 344b20–24. In GA IV, 6, 775a11–13, for example, Aristotle describes what happens when an animal develops and comes to be in terms of διάκρισις. 49 This claim is made for instance in GC I 3, 339a36–b2, GC II 2 329a35–b1, and 329b22– 24. In what way they are transformed into each other is discussed in GC II 4. 50 For the change from air to water for instance, i.e. the coming to be of water and the 92 Locomotion necessarily accompanies each of the other kinds of change ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen