Aristotle's "review of the literature," his survey of previous views concerning causation, is helpful as always. It's mind-boggling that what we know of some of these philosophers, we know from him. (Poor Hippo, of whom Aristotle says only that "one would not consider him worthy of being included... because of the shallowness [paltriness] of his thought." Ouch!)
I've become quite conscious of some serious translation slippage with this reading. The historian-of-relatively-recent-American-English-speakers' ideas in me is inclined to slog through the Metaphysics in Greek, the better to get Aristotle's original meaning. But even with considerably better Greek than mine is at the moment, that quest for "original meaning" is doomed.
One major point of this reading is to get a handle on where things shifted in translation, where Aristotle's writings τὰ μετὰ τὰ φυσικά, "the stuff after the physics" or maybe "the stuff that goes beyond the physics," became Aristotle's Metaphysics, which is something altogether else. This change occurred at the hands of editors, translators and commentators who thought and wrote variously in Aristotle's Greek, in later Greek, Latin, Arabic, German, French, English and in many other tongues. Among them were non-Greek pagans, Muslims, Christians (Medieval and Modern), Enlightenment scientistic thinkers, and twentieth century scientific naturalists. Throw in a few Wicca and Cylons, for all I know.... the point is that they could each deposit a distinctive interpretive layer on "Aristotle's original meaning." The end result is whatever we, today, can think about concepts such as "substance" and "essence" and "cause."
So, some terminology/etymology stuff.
"Cause" is apparently Cicero's translation for Aristotle's aition, which in Greek meant the answer or response to a question (Randall 123-24). In "The Question Concerning Technology," Martin Heidegger makes much hay of this slippage: he argues that the so-called "Four Causes" are not meant to give accounts of how something came to be in our accustomed sense. Rather, they give an account of what is "responsible" for a thing.
"Essence" is a later accretion altogether. It often translates the mysterious phrase "to ti en einai," literally something like "what it (this thing) is/was being." As Randall notes,
no single term corresponding to the Latin essentia, "essence," occurs in Aristotle. Aristotle used at least a half a dozen terms which can all be translated, in some contexts, as "essence." What complicates the matter is that they can all be translated in certain other contexts as definitely not meaning "essence." Ousia is the most troublesome and misleading of these ambiguous terms. (Randall 121 n.18)
"Substance," of course, is our translation for ousia.
My head hurts.