The Priority of Locomotion in Aristotle’s Physics

Abstract

The Priority of Locomotion in Aristotle’s Physics aims at looking at the four types of change. In each of the four examples a change is described, yet the way in which the respective subject changes is different in all four cases. In fact, each of the examples stands for one of the four respects in which according to Aristotle change (κίνησις/μεταβολή) may occur.1 Something x may change in respect of substance (κατ᾽ οὐσίαν), quality (κατὰ ποιόν), quantity (κατὰ ποσόν), or place (κατὰ τόπον), that is to say, the subject may undergo generation and corruption (γένεσις καὶ φθορά), alteration (ἀλλοίωσις), growth and diminution (αὔξησις καὶ φθίσις), or locomotion (φορά).2 In Book VIII of the work which we call the Physics, but also in other places, Aristotle claims that of these four types of change the latter, i.e. locomotion, in general should be considered the most important and primary (πρώτη τῶν κινήσεων), in that it has priority over the other types in different ways3, which for instance finds its expression in the fact that according to Aristotle there is no change in quality, quantity, or substance without locomotion, while the converse does not hold. Aristotle often uses both κίνησις (motion) and μεταβολή (change) in referring to the four different kinds of change he thinks exist. In Phys. V 1 and 2, however, he explicitly distinguishes the terms from one another: κίνησις only covers the three kinds of non-substantial change, namely change in place, quality, and quantity, while μεταβολή is used as the more general term, and stands for all of the four kinds of change, i.e. for the non-substantial kinds as well as for change with respect to substance (see Phys. V 1, 225a34–b3, V 2, 226a23–25 and 226b8–10). I will use ‘change’ for both κίνησις and μεταβολή where the difference between the terms is of no importance, and render κίνησις as ‘non-substantial change’ when the context suggests that κίνησις is restricted to this sense