Seite - 132 - in The Priority of Locomotion in Aristotle’s Physics

something x’s change in temperature, this would mean that after becoming hot it cools down again, after which it changes its temperature to hot again and so forth ad infinitum. Similar examples can be made for alteration, generation and corruption. Aristotle, however, argues that such a succes- sion of changes cannot be one and continuous, since—and this is the crucial point—the time in which any of these changes would occur is necessarily intermitted at some point, so that the succession of these changes cannot be considered as a continuous whole. The reason for this claim is the follow- ing. The starting point and the endpoint of each of the other three kinds of change, Aristotle tells us in this chapter, are opposites to one another, so that each of these changes occurs between opposites.49 In the case of altera- tion, these opposites are the contrary qualities, for change in quantity, i.e. growth and diminution, smallness and magnitude, and for generation and corruption, the contradictory opposites of being and non-being.50 It is this fact which rules out that a single change in quality, quantity, or substance may be eternal merely in virtue of the subject’s going back and forth between starting point and endpoint an infinite number of times. For according to Aristotle, this would entail that something x at one and the same time undergoes contrary changes, which is impossible.51 The conse- quence of this is that x needs to come to a standstill before undergoing a change that is contrary to the one x underwent before, so that, as Aristotle puts it, a certain amount of time will elapse between the two changes; but if there is a time of rest between two changes, then these two changes cannot form one continuous whole, since the criterion of unity in time is not ful- filled: “So that if it is impossible that something changes in opposite ways at the same time, the change will not be continuous, but there will be some time between them”, i.e. between the opposite changes.52 The following example should illustrate the idea that seems to inform Aristotle’s argument: it would be contradictory to say that something x, in undergoing a change in temperature, at the same time is changing from hot to cold, but in another sense it would not, as it is also changing from cold to hot. Or, to put it the way Aristotle does in the cited passage, x at the same time would be undergoing opposite changes, namely from hot to cold and 49 ἅπασαι γὰρ ἐξ ἀντικειμένων εἰς ἀντικείμενα εἰσιν αἱ κινήσεις καὶ μεταβολαί, Phys. VIII 7, 261a32–33: “For all non-substantial changes and changes are from opposite to opposite”. 50 See Phys. VIII 7, 261a34–36. 51 See Phys. VIII 7, 261b15, and especially Phys. VIII 8, 264a28–29 where this principle is formulated most explicitly: ἅμα δὲ μὴ ἐνδέχεται κινεῖσθαι τὰς ἐναντίας. 52 ὥστ᾽ εἰ ἀδύνατον ἅμα μεταβάλλειν τὰς ἀντικειμένας, οὐκ ἔσται συνεχὴς ἡ μεταβολή, ἀλλὰ μεταξὺ ἔσται αὐτων χρόνος. Phys. VIII 7, 261b5–7. 132 All changes depend on the first locomotion, but not vice versa ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen