This essay is a commentary on Physics I, with special reference to the account of change in chapter 7. It is argued: (i) that Aristotle is mistaken when he attempts in the earlier chapters to present his account as the natural development of various Pre-Socratic views ‘on nature’; (ii) that as a result the main theme of his chapter 5 is a clear error; and (iii) that this raises an important question over how we should understand the apparent claims of chapter 6. All of this leads to the problem: How should we explain his remark at the end of chapter 7 that it is not yet clear whether the underlying thing, the thing that persists through change, is substance?
Keywords: Aristotle, Physics, substance, change, persisting things, underlying things, matter, form