Yesterday, I changed my thinking about Aristotle’s “efficient cause”, making a somewhat surprising connection to the modern notion of “structural causality”. Then I had to update my account of generalized unmoved movers to add a case for an unmoved efficient cause.

Aristotle’s whole framework of “causes” (answers to “why” questions) is often misunderstood, and it is especially bad with the so-called efficient cause. A quick web search on the latter turns up mostly accounts that are just wrong. (A wonderful exception is the outstanding article in the Stanford Encyclopedia of Philosophy).

At Physics 195b22-25, referring back to an earlier example of a man building a house that was initially said (metonymically, it turns out) to be an efficient cause, Aristotle wrote (Complete Works, Barnes edition) “In investigating the cause of each thing it is always necessary to seek what is most precise (as also in other things): thus a man builds because he is a builder, and a builder builds in virtue of his art of building. This last cause then is prior; and so generally.” So it is the art of building — not the carpenter or the hammer or the hammer’s blow — that primarily “builds” the house (i.e., governs the details of the process its construction), and is properly (not just metonymically) called its efficient cause. Once again, for Aristotle it is something at the level of adverbial detail — not the coarse level of agents or action — that is most important.

Having said the other day that Foucaultian discursive regularities are a kind of efficient cause like the art of building, it occurred to me they are also a good example of structural causality, and then that one might say the same about, e.g., the art of building.

Previously, I had been thinking about the efficient cause as functioning like a sort of catalyst. This relatively modest role had led me to privately think of the efficient cause as an “accidental” cause (i.e., one not really contributing to the essence of the thing).

This was at the opposite extreme from the tendency of late scholastics like the great Jesuit Francisco Suárez (1548-1617) to make efficient causes paradigmatic for causes in general, conceived in a proto-modern sense of being responsible for the fact of a thing’s being or existence rather than for the manner of its being, and as involving an “influence” from an agent rather than reasons. (In this context, ends or “final causes” were also reduced to mental intentions of a natural or supernatural agent, as al-Ghazali (d. 1111 CE) had done earlier, quite contrary to Aristotle’s own non-mental account. It was this mentalist reinterpretation that was the real target of Spinoza’s eloquent polemic against against teleology.) There is a nice article by Stephan Schmid on these issues in Suárez.

Anyway, an efficient cause as a point of application of structural causality clearly has a much bigger role to play in determining the detailed nature of a thing than the purely external one of a mere catalyst. (I am using the word “nature” here in a sense broader than Aristotle’s, similar to essence but particular to things that come to be, whereas Aristotle further limited it to nonartificial things, which he thought all contained at least a rudimentary internal principle of motion not shared by artificial things.) On my new account, the efficient cause also exemplifies the interweaving of Aristotelian essence with accident or contingency, due to the role of the semantic materiality as well as form of the means of realization of a nature that is its efficient cause.

This is also more conformant to the idea that all Aristotelian causes are supposed to contribute to explaining the natures of things. Ironically, my previous “catalyst” view made the efficient cause a kind of exception that looked more like the sort of cause of existence I have generally been arguing is un-Aristotelian. As a point of application of structural causality, an efficient cause now fits the general pattern of explaining natures, rather than the mere factual existence of things with natures more or less taken for granted.