Page - 97 - in The Priority of Locomotion in Aristotle’s Physics

That undergoing aggregation and segregation imply that the respective subject changes with respect to place in a sense becomes even clearer when we think back to the examples of these two processes given above. As we have seen, an elemental body’s undergoing either of the two processes goes hand in hand with its increasing and decreasing in size, as water for instance by being heated undergoes segregation and expands in volume before finally being transformed into air. From the discussion of the con- nection between change in place and change in quantity we have seen that something necessarily undergoes a change in place with respect to its parts when it changes in size.68 Therefore, the aggregation or segregation of a portion of a certain element implies an increase or decrease in size, and hence involves a change in place with respect to the element’s parts. This is even more obvious for cases of generation in which a new sub- stance comes to be from different parts and for cases involving the corrup- tion of such a substance. The process of aggregation or combination under- gone by the material components from which a new whole is coming to be needs to involve a change in place of these components, since they have to move together in order to form one new continuous body. The same is true of corruption: if a body undergoes segregation and dissolves into its mate- rial components in the process of corruption, these parts need to change with respect to place. 4.3.4 Conclusion Thus, in the way I have presented above, Aristotle is right to claim that what undergoes aggregation or segregation necessarily changes with respect to place, namely with respect to its parts. As in the case of change in quan- tity, that which is coming to be or is perishing does not change in place as a whole, but with respect to its parts, that is, its basic material components. As with respect to change in size, this argument has shown that generation and corruption is always accompanied by a change in place, while there is no reason to assume that the converse must hold. Therefore, in examining what happens on the material level when generation and corruption occur, it has turned out that both processes, as growth and diminution, presup- pose and necessarily go hand in hand with change in place, and cannot take change in place is also clear from what Aristotle states in the passage in Phys. VIII 9 in which he tries to show that his predecessor’s assumptions—at least implicitly—also presupposed that change in place is primary. There he explicitly states that aggregation and segregation are changes in place (διάκρισις γὰρ καὶ σύγκρισις κινήσεις κατὰ τόπον εἰσίν, Phys. VIII 9, 265b19–20). 68 For this see section 4.2.2. What undergoes generation or corruption changes with respect to place 97 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen