Page - 203 - in The Priority of Locomotion in Aristotle’s Physics

certain sense and, as we have seen, may only occur in virtue of this change in place. This, however, seems to be in conflict with Aristotle’s claim that locomotion has essential priority, since its subject then, as we have seen, in no way seems to depart to a lesser extent from its essence than the subject of alteration, growth or diminution. The solution to this problem is that both of the cases of locomotion that are contrasted here with each other differ with respect to what the actual subject of the respective change in place is. In the first case that which is said to change in place undergoes locomotion as a whole and therefore in the strict sense indeed is not changed in any other way than with respect to its place. In the second case, however, that which is said to change in place does so with respect to its parts, which is a completely different situation.79 In the argument that I am discussing at the moment, Aristotle, thus, seems to be claiming that any subject x, in undergoing a change in quality or quantity as a whole, is departing from its essence, while this is not the case for that which undergoes change in place as a whole. Otherwise, the claim that locomotion does not change the being of its subject would not make any sense at all, because something changing in place with respect to its parts, as we have seen, may very well lead to its corruption. Therefore, in order to find an appropriate solution one needs to compare change in qual- ity, quantity, and place insofar as they are undergone by a subject as a whole. Against this background my suggestion is that what Aristotle has in mind when he claims that x undergoing a change in quality or quantity as a whole implies x’s departing from its essence is that these kinds of change in princi- ple may result in a change of essence, while this is impossible for locomo- tion. In what follows I will state the reasons for this claim in more detail. Let us start by examining in what way this is true with respect to altera- tion. My claim is that certain alterations something x may undergo as a whole can result in x undergoing a change in essence in the sense that if the alteration goes on for too long and in consequence the respective quality becomes too extreme this ultimately results in a change in substance. Sup- pose, again, I have a fever, that is, my temperature rises and my body becomes hot. This alone does not yet lead to my corruption. But if this change in quality, i.e. the heating of my body, were to continue, it would result in my corruption at some point. That this is what Aristotle has in mind is supported by a passage in the Topics. There it is stated that, if an affection is intensified and increased, this changes the substance and—to 79 For the difference between x changing in place as a whole as opposed to its changing in place merely with respect to its parts, and in what way the first does not involve a change of x in the manner described, while the latter does, see my discussion of the second argument, esp. sections 4.2.2 and 4.2.3. Locomotion alone preserves its subject’s essence 203 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen