Page - 111 - in The Priority of Locomotion in Aristotle’s Physics

of aggregation and segregation on one occasion are characterised with reference to condensation and rarefaction on another. The evidence I will present is once again based primarily on passages from the Meteorology, although more relevant passages may be found in other places. In some places, for instance the change from air to water is described as aggregation (σύγκρισις), while in others the very same process is termed condensation (πύκνωσις).108 Another example is the explanation of certain phenomena of light that occur in the sky: Aristotle accounts for these phe- nomena as being the result of an aggregation of air in the heavens. The more a portion of air is aggregated (συγκριθῇ), the easier it is to ignite. Conversely, things are described as being less likely to catch fire when they are in a state of rarity (μανότης).109 But if for Aristotle condensation and rarefaction indeed are kinds of aggregation and segregation, why does he not simply say that the latter are sources of all qualities, rather than introducing what seems to be a superflu- ous premise that uses the terms πύκνωσις and μάνωσις? My assumption is that although it is right to say that every condensation is an aggregation and every rarefaction a segregation, the converse does not hold. Rather, condensation and rarefaction seem to be sub-classes of aggregation and seg- regation. The difference between πύκνωσις/μάνωσις and σύγκρισις/διά- κρισις is that the former two terms seem to be restricted to changes under- gone by a subject that has some kind of unity. A certain portion of earth or water, for instance, can undergo condensation or rarefaction, since the respective portion can serve as one continuous thing due to its continuity and therefore can expand or contract by being either condensed or rarefied. Speaking of these two processes presupposes a subject that is characterised by some basic kind of unity, as it does not make sense to say that for exam- ple two drops of water undergo one process of condensation. The situation is different for σύγκρισις. As I think the examples show, the term aggregation basically encompasses all cases of condensation. But in addition it also covers cases in which one thing comes to be from a com- bination of other separate things. For example it is possible that two differ- ent things, e.g. two portions of water, undergo aggregation and combine 108 For the transformation from air to water as σύγκρισις see for instance Mete. I 3, 341a4 and 341a9–10. For the characterisation as πύκνωσις see Mete. I 12, 348b10–12, III 2, 372b30–33, and III 2, 372b22–24. In the latter passage Aristotle talks about the process by which vapour, that is very moist air, is turned into water. The reverse process from water back to vapour accordingly is called a διάκρισις in Mete. I 3, 340b3. 109 For the first see Mete. I 5, 342b16–17, where it is stated that these phenomena often appear in the night sky “when [air] becomes further aggregated” (ὅταν συγκριθῇ μᾶλλον), for the second Mete. III 1, 371a27, where an object is said to be less ignitable by a fiery wind, because of its rarity (for the whole context of this see l.15–27). What changes in quality changes with respect to place 111 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen