Seite - 110 - in The Priority of Locomotion in Aristotle’s Physics

have in common that each of them is connected with a certain state of den- sity. When there is an alteration and the quality changes, there is always a concomitant change with respect to density, that is, condensation or rare- faction. By referring to these two processes one can explain part of what happens when something undergoes alteration, namely that its basic mate- rial components, or at least some of these, change with respect to density. And this is the sense in which πύκνωσις and μάνωσις may be called a principle or source (ἀρχή) of all qualities. Of course this does not mean that the basic qualities, much less any quality, can be reduced to states of rarity and density or changes in these qualities to condensation or rarefaction, although this passage has been understood this way.106 To evaluate the argument, one needs to have its context in mind. Aristotle is referring to condensation and rarefaction as essential parts of alteration in order to show that alteration, too, necessarily involves change in place and that loco- motion therefore is prior to alteration. Therefore, there clearly is a certain sense in which one could correctly argue that alteration has its source in condensation or rarefaction, namely by focusing on special processes that occur on what one could call the mate- rial level. Yet, this alone of course does not show that locomotion is the pri- mary kind of change. In order to reach this goal another step is taken by Aristotle in his argument. This next step is to identify condensation and rarefaction with aggregation and segregation, the latter of which, as I have already argued, necessarily involve a change in place. Therefore, I will now examine whether Aristotle’s claim that “condensation and rarefaction are aggregation and segregation”107 is correct. 4.4.5 Condensation and rarefaction are forms of aggregation and segregation To my knowledge, there is no other place in which Aristotle explicitly says anything about the relation between condensation/rarefaction and aggrega- tion/segregation. Therefore, I will attempt to characterize the relation between them by examining his use of the terms (rather than by examining what he explicitly says about them). The way in which the terms are applied clearly suggests that the claim about the relation of the two pairs of phenomena as it is stated in Phys. VIII 7 is indeed what Aristotle has in mind, and not, as one might think, merely a reference to the theory of an earlier philosopher. For there are some pas- sages in Aristotle in which processes in nature that are described in terms 106 Therefore, I do not agree with Graham (1999), 122, who thinks that in this argument “Aristotle seems to reduce apparently simple qualities to condensation and rarefaction”. 107 πύκνωσις δὲ καὶ μάνωσις σύγκρισις καὶ διάκρισις, Phys. VIII 7, 260b11. 110 Locomotion necessarily accompanies each of the other kinds of change ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen