Page - 79 - in The Priority of Locomotion in Aristotle’s Physics

as a whole—after all, the parts of the infant’s body grow in such a way that their growing taken together constitutes a change in quantity of the infant as a whole. Of course, it is not the case that if all parts of x change, x neces- sarily changes as a whole. But with respect to the stated example one needs to be able to explain why, contrary to what one might expect, the change in place of all the parts, which derives from their change in quantity, does not imply that the infant changes in place as a whole. Therefore, let us suppose now that there is a case in which x’s growing as a whole leads to a process in which all parts of x change in place. Again, one may ask what the difference is between x’s parts changing in size and the very same parts changing in place—for it is this difference that will explain why according to Aristotle x in undergoing a quantitative change never undergoes a change in place as a whole, but merely with respect to its parts, even when all of x’s parts are changing in place. Let us return to what Aristotle says about the difference between what he calls locomotion in GC I 5 and the change in place that x undergoes in virtue of growing. As we have seen, to say that x is subject to the former means that it changes in place as a whole, while to say that it is subject to the latter implies a change only with respect to its parts. If I move my arm, i.e. change in place merely with respect to a part, it is clear that I do not change in place as a whole. But in the case in which all of x’s parts change in place it is less obvious why this does not count as a change undergone by x as a whole—especially as it derives from the change in quantity that x undergoes as a whole. Although he does not explicitly state this, Aristotle seems to be well aware of this difficulty and therefore says something more about the way in which the change in place of that which grows differs from the change in place that something undergoes as a whole. I have left out this additional explanation in the quotation thus far in order to focus in this preliminary investigation on the basic difference between the two ways in which some- thing can change with respect to place. In the full passage from GC I 5 the case in which something changes in size and thereby undergoes a change in place with respect to its parts is contrasted with the case of the locomotion undergone by a perfect sphere revolving on its own axis. The sphere always occupies the same space and for this reason like the subject of growth seems to “remain” (μένοντος), although by rotating it undergoes a change in place as a whole.21 Now if the parts of the growing infant in our example were to change in place in the same way as the parts of the revolving sphere, then there would be no reason to say that the former is less a change in place as a whole than the latter. 21 For the explanation why the revolving sphere changes in place as a whole see Phys. VI 9, 240a29–b7. What changes in quantity changes with respect to place 79 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen