It turns out that Aristotle’s way of arguing for a first cause in book Lambda of the Metaphysics depends almost entirely on his unusual thesis of the priority of actuality or being-at-work or fulfillment over potentiality. His justification of the priority of actuality there also seems unexpectedly Kant-like, which means that so does his argument for a first cause.
We don’t positively know that actuality is prior, or that there is a first cause. Rather, Aristotle makes the indirect argument that a priority of actuality is a necessary condition for the kind of intelligibility that we need to have in order to be able to explain things at all. The pure actuality he attributes to the first cause is part of his affirmation that the priority of actuality is not an optional feature of his account.
I have been very impressed by Robert Pippin’s account of how Hegel’s rediscovery of the Aristotelian priority of actuality affects ethics and the theory of agency. Gwenaëlle Aubry increased my sensitivity to the normative, end-like character of Aristotelian actuality itself, and to his repeated associations of the first cause with the good and the beautiful. I’ve always read Aristotle’s first cause in terms of that-for-the-sake-of-which — as a sort of ultimate end — so this was a welcome perspective. This much seems to tightly cohere, and all to be nicely confirmed by the somewhat more disciplined reading of the Metaphysics I’ve just finished.
But I’ve been neglecting another strand from the Physics, which defines motion in terms of actuality and potentiality, and which ultimately traces every motion to the realization of an end, and to the actualization of a potential. Given my own interest in the idea of interpretation in an ethical spirit as first philosophy, this suggestion that material motion as such is in some minimal way ends-governed — even when no living plant or animal is involved — is something I find very appealing, albeit in need of clarification.
On the other hand, the arguments about a first motion and a first moved thing associated with the sphere of the fixed stars presuppose the non-relative status of a geocentric point of view in astronomy, and I don’t see any way to sustain that. The first cause of all things can no longer be conceived as having a special, more direct relation to the motion of the stars as viewed from earth, such as Aristotle suggests.
But we can still say that the pursuit and partial realization of the good and the beautiful are in a way involved in motions in general. This can be defined in a way that depends only on observable patterns of how various kinds of material things tend to seek completion in one way rather than another in different situations.
The good and the beautiful will be a “prime mover” only in this more diffuse sense, not as also having a special relation to the motion of the fixed stars. But we can still have entelechy from top to bottom, and we can still be moved by the beauty of the stars.