IN GENERATION AND CORRUPTION 2.9, Aristotle sets out to give an account of "how many and what are the principles of all coming to be are like." (1) In doing so, he situates the cause "for the sake of which," [TEXT NOT REPRODUCIBLE IN ASCII], within a causal nexus familiar to readers of Physics 2. It is constituted by the end--that is, the form produced--by the matter in which it is produced, and by the agent that produces it. In Meteorology 4.12, moreover, he explains that form itself must be understood in terms of the species-typical activities that follow upon its presence and for the sake of which the composite substance exists. He thus recognizes two sorts of ends, form and activity, of which the latter seems to be ultimate. Although form is the immediate end of coming to be, a composite substance exists in the last analysis for the sake of its activity.
In the following pages, I argue that the foregoing statements implicitly contain a simple yet complete account of Aristotle's teleology. In De anima 2.1, Aristotle states that the term "actuality" ([TEXT NOT REPRODUCIBLE IN ASCII]) signifies both form, or first actuality, and activity, or second actuality. (2) Form is the actuality of a natural body, in other words, but this actuality brings with it a capacity for further actuality--that is, for activity of a certain kind. If, however, both form and activity are ends, then that for the sake of which seems to coincide perfectly with actuality. This conclusion entails that the roots of Aristotle's teleology are not bound up with his biology, as several contemporary writers have suggested. (3) They are not even to be found in his understanding of nature in general, but rather in his first philosophy or metaphysics.
Although I am not primarily concerned with the theological dimensions of Aristotle's teleology, the question of God will appear early in the following discussion and reappear several times, reminding us of the need for a properly metaphysical analysis. As Metaphysics 6.1 tells us, it is the existence of an immovable substance or substances that distinguishes the science of nature from first philosophy. (4) Indeed, Aristotle's theological commitments reveal that an accurate account of his teleology cannot depend on the notion of change, even change for the sake of an end. As we shall see in a moment, he himself highlights the problematic relation between that for the sake of which and change when he asks, in the Metaphysics, how final causality can pertain to unchanging substances such as God.
Our immediate point of departure, however, is the claim in Physics 2.2 that every outcome of a continuous change, provided that it be "what is best," is an end. In section 1, after briefly introducing this text, I lay out a serious challenge that any interpreter must face. This is Aristotle's suggestion, in the theological aporia just mentioned and in its later resolution, that there cannot be a strong, general connection between [TEXT NOT REPRODUCIBLE IN ASCII] and motion or change. This section concludes with a brief clarification of Aristotle's use of the term "motion" [TEXT NOT REPRODUCIBLE IN ASCII] as opposed to "change" [TEXT NOT REPRODUCIBLE IN ASCII], the text from Physics 2.2.
In section 2, I begin to address the challenge formulated in section one by showing that theology aside, Aristotle's account of natural substances precludes any account of [TEXT NOT REPRODUCIBLE IN ASCII] in terms of motion. This is because every composite substance is, simply as such, for the sake of its form. Then, having considered the inadequacy of motion as a context for understanding Aristotle's teleology, we shall turn to the more basic, metaphysical concept of actuality. It is in terms of actuality, I shall argue, that Aristotle provides a unified account of both being for the sake of an end, which need not involve motion, and the more familiar coming to be or change for the sake of an end, which obviously does. …