I now have an Aristotelian account of structural causality. It is exercised by the combined form and materiality of actually used means to desired ends, and behaves like a contextual unmoved mover. As usual with Aristotelian “causes”, this puts it in the context of an expressive semantics, rather than any mechanical metaphor. (See also What and Why.)
We choose among available means to our ends (and, I think, also among alternative derived ends, due to the interdependence of derived ends with means). Then through structural causality, each such choice brings with it a block of consequences that are not up to us. This reconciles structural causality with contingency and Kantian freedom. (See also Potentiality, Actuality; Structure, Potentiality; Efficient Cause.)
Notwithstanding Brandom’s negative comments in passing about structuralism, I think a similar account of the place of structural causality can be applied in the context of Brandomian choice and practical endorsement of commitments.