The role, structure and status of Aristotle's Physics I

The essay addresses the general issues of the role, structure and status of Physics I. First, I seek to clarify the sense in which Physics I is the beginning of Aristotle’s physical project. I argue that, although Physics I’s inquiry is of a scientific and physical kind, it is a relatively free-standing treatise, which plays an introductory role aimed at, as it were, setting the scene for the project as a whole. I highlight various clues that show Physics I’s introductory role: the way in which it describes the central object of natural science (i.e. natural substances), the evidence it uses, its heuristics, its peculiar relation with the tradition of natural philosophy, the way it identifies and describes the principles of natural substances. In order to clarify further the role of Physics I, I explore the relation between this book and other parts of the corpus. In particular I consider Physics I’s assumptions and background (by focusing especially on Physics I’s relations with the Organon) and the connections between Physics I and what comes next in Aristotle’s physical enterprise. I also focus on the overall argumentative strategy of the book, addressing its various schemes of construction and the order in which the principles are introduced in Physics I–II. I argue that the particular mode of inquiry adopted in Physics I-II is especially useful, perhaps required, in constructing a correct theory of principles. Further, I suggest that the principles argued for by Aristotle in Physics I are the essences of the things that play the role of principles as such: they are the ti esti of principles, and this is why they are first principles.