Page - 176 - in The Priority of Locomotion in Aristotle’s Physics

case, which then raises the question whether there are kinds of living beings in whose development locomotion is not last. For this reason, I do not think that Aristotle’s assumption was based on mere observation—at least not primarily. As I will now show, this assumption is in accordance with and follows from his theory of the soul as it is stated in the De Anima. In fact, the first of the two arguments for locomotion’s priority in essence presup- poses this theory without mentioning it explicitly. Accordingly, I will now deal with the aspects of this theory that are of importance to my under- standing of this argument. 7.1.4.1 Capacities of the soul According to Aristotle, the soul as the principle of life of living things has different capacities.24 Which capacity the soul of a certain living being has depends on what kind of living thing it is. A plant’s soul, for instance, only has the capacity of nutrition that is responsible for a living thing’s nourish- ment, growth and reproduction.25 But the soul of every other living being also has this capacity. More highly developed forms of life, however, have additional capacities which plants lack. All animals, in contrast to plants, for example are able to make perceptions and therefore have a certain capa- city that is responsible for this kind of sensory activity. As we have seen, some, but not all, of the animals have the capacity to move from place A to place B. According to Aristotle’s theory, such animals, in contrast to sponges or other animals of that kind, therefore have a soul which may be the source of their self-motion, or to put it in other words, they have a soul which has the locomotive capacity.26 As we have seen, the argument under discussion clearly refers to such capacities, as the term ‘locomotion’ does not mean ‘change in place’ in gen- eral, but rather stands for the capacity to cause one’s own change in place.27 In this sense x has locomotion, if it can cause its own change in place. As I said, the argument presented may show that the capacity to self-locomote is prior in essence to the capacity to perform any of the other changes, rather 24 The difference between things that have a soul and those that do not lies in the fact that the former have life while the latter do not (see de An. II 2, 413a20–22). The soul is the princi- ple (ἀρχή) of the kind of activities that are specific to things that live (see for instance de An. II 2, 413a22–25 and 413b11–13). 25 See for instance de An. II 2, 413a31–b1. 26 See for instance de An. II 4, 415b21–23. 27 See p.173. This also seems to be in accordance with comparable passages in the De Anima where Aristotle for instance says that ‘x has perception’ and obviously means that x has the capacity to perceive (see for instance de An. II 3, 414b4, III 3, 427b11–12, and III 11, 433b31–434a2). 176 Locomotion is prior in essence ISBN Print: 9783525253069 — ISBN E-Book: 9783647253060 © 2014, Vandenhoeck & Ruprecht GmbH & Co. KG, Göttingen