Page - 205 - in The Priority of Locomotion in Aristotle’s Physics

engaging in a kind of change that, were it to continue, would lead to x’s change in essence. Growth and diminution may be said to be responsible for their subject departing from its essence, as it in principle may, but does not have to, result in a change in essence. As we have seen, to say that something x is departing from its essence does not imply that it at some point actually completely changes in essence. Metaphorically speaking one might say that when x begins to undergo a change in quality or quantity the first step towards a change in substance is taken; whether this ultimately leads to a corruption of x is another question. That this is correct appears more likely if one understands ἐξίσταται τῆς οὐσίας in the sense of ‘embarking on the process of departing from the essence’, that is, by emphasizing the ingressive aspect of this form. This can be made clearer by considering the following analogy. Suppose I leave the university building in Berlin and start walking north. If I keep on going long enough I will leave Berlin at some point. But it is not until I have crossed the city’s border that I will actually have left Berlin. Yet, in a sense one may say that, although I am still in Berlin when I walk out of the build- ing, I am nonetheless already in the process of departing Berlin at this moment in the sense that I am engaging in a kind of change that, were it to continue, would finally result in my crossing the city’s border. In the same sense, I take it, one may speak of something x departing from its essence in undergoing change in quality or quantity as a whole. For, as I showed, these changes may, but do not have to, lead to x’s change with respect to essence. The situation however is completely different when x as a whole under- goes a change in place, since this cannot lead to x’s change in essence. This has already been made clear in previous discussions. If x undergoes loco- motion as a whole, none of what I called the intrinsic qualities change, nor would this be the case with respect to the inner spatial order of its parts, as I put it in the discussion of the second argument. Both, however, seem to be necessary for x to change in essence. In addition, one could also say that the reason for the fact that locomotion does make its subject depart from its essence is that the mere change in place of x as change in place can never result in a change of x’s essence. But there are examples which seem to suggest that undergoing a change in place does result in a substantial change. Suppose, for instance, I have a fish tank with one goldfish inside. One day the gold fish jumps out of his fish tank and lands on the table, where it suffocates. Another example would be me for some reason walking into a burning house and perishing in the flames. Both examples are cases of corruption, that is, of a substantial change. For both examples, one may say that the subject’s undergoing locomotion as a whole leads to the destruction of the subject, since corruption would not have occurred without the preceding locomotion. Yet, it is important to Locomotion alone preserves its subject’s essence 205 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen