Page - 47 - in The Priority of Locomotion in Aristotle’s Physics

can be transformed into flesh and in this sense is potentially like that to which it is added. In the sense stated above, therefore, the food which is added is actually something unlike the growing thing, but also is potentially something like the growing thing, which is exactly what claim (1) says.14 That this must be what Aristotle has in mind here becomes even more clear in a passage from de An. II 4, where it is stated that the food, “insofar as it is undigested, is the contrary for the contrary, but insofar as it is digested, is the like for the like.”15 This, however, is a short reformulation of what I just stated, namely that growth indeed seems to take place by means of that which is like and— at the same time, yet in another respect—unlike the growing thing. But in order for the growth to occur the nourishment’s potential of being like that to which it is added has to be actualised. In terms of Aristotle’s explanation from GC I 5, the food, among other things, needs to be changed from moist to dry, that is from the quality by which it is characterised into this quality’s contrary. A change from a quality to its contrary, however, is an alteration.16 Since, as we have seen, such a change needs to occur when the food is transformed in order to become an integral part of the body, Aristotle correctly makes claim (4), i.e. that this change (μεταβολή), which involves a change between these contraries can only be an alteration (ἀλλοίωσις).17 Therefore, Aristotle rightly claims that an alteration, at least in the stated case, has to precede growth in the sense that before the material becomes a part of the body by being integrated into it, it must first undergo an altera- tion. One way to think of this in Aristotelian terms would be the following: in order for the growth of the animal to take place, food has to be digested, that is, turned into blood and later for instance into the homoeomeres of flesh or bone. This involves an alteration, since this process, parts of which involve the change from wet to dry, takes place by concoction (πέψις), i.e. the heating of the food.18 Hence, every process of growth which works in this way has to be pre- ceded by an alteration. In this way Aristotle shows that this is what must happen whenever an animal grows; yet, he does not make clear that its decrease in size, i.e. diminution, also presupposes alteration in the stated 14 See GC I 5, 322a5–6. 15 ᾗ μὲν γὰρ ἄπεπτος, τὸ ἐναντίον τῷ ἐναντίῳ τρέφεται, ᾗ δὲ πεπεμμένη, τὸ ὅμοιον τῷ ὁμοίῳ. De An. II 4, 416b6–7. 16 See for instance Phys. V 2, 226b1–3, GC I 4, 319b8–12, where ἀλλοίωσις is defined as the change between contrary qualities of some x. The example that in GC I 5 is given for this change is that of nourishment being changed from wet to dry (see 322a1–3). 17 ἀνάγκη οὖν ἀλλοίωσιν εἶναι τὴν εἰς τἀναντία μεταβολήν. Phys. VIII 7, 260a34. 18 See PA II 3, 650a2–6. Growth and diminution presuppose alteration 47 ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen