Seite - 134 - in The Priority of Locomotion in Aristotle’s Physics

of the four kinds of change apart from change in place can form one contin- uous change that is eternal. 5.3.2 Only circular locomotion can be one and eternal After this Aristotle goes on to show why most of the different kinds of loco- motion also cannot form a change that is one and eternal in the necessary sense. The only kind of change in place that can be eternal in the appropri- ate way, he claims, is circular locomotion. The basic reason Aristotle pre- sents for the stated claims is that as in the case of the other types of change most kinds of change with respect to place necessarily involve an intermit- tence in time, and therefore cannot be one and eternal without qualifica- tion. This, however, as we will see, is not the case with circular locomotion, since an eternal motion that consists of one and the same locomotion along a circular path in no way involves contrary motions and in contrast to all changes does not have to stop at some point. I will now present the reasons for each of these claims, which are presented in Phys. VIII 8 in more detail. Once again, I will focus on presenting the basic assumptions that must be made if one is to understand Aristotle’s claims, insofar as these are impor- tant for my inquiry; thus, I will not examine the whole passage here in detail. There are three types of local motion, namely circular locomotion, recti- linear locomotion and locomotions which consist of a mixture of both types.55 If straight or circular locomotion cannot be one and eternal in the appropriate way, then, of course, the same must be true of the mixed motion which is composed of both types.56 First of all, it again seems to be clear that straight locomotion cannot exist continuously, because this kind also has a certain limit (πεπερασμένη).57 Accordingly there cannot be a rectilinear locomotion along an infinite path. This seems reasonable if one bears in mind that Aristotle thinks that the extension of the cosmos is finite and that a rectilinear locomotion for this reason cannot go on forever, since its subject will reach the limits of the universe at some point. But as in the case of the other kinds of change one might think that a change in place along a straight line could be one and eternal if the subject were to go back and forth between the place from which its starts and the place which is the endpoint of this (part of the) change. Yet, according to Aristotle such a change, too, would involve an intermittence of time, i.e. a state of rest in 55 See Phys. VIII 8, 261b28–29. 56 See Phys. VIII 8, 261b29–30. 57 See Phys. VIII 8, 261b32. In fact it is stated for instance in Phys. III 6, 206a16, that no magnitude (μέγεθος) can be infinite in extension. 134 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