Following is a summary of, much of it quotes and paraphrases from, Chapter 8 of A Metaphysics for Freedom by Helen Steward. It is the last chapter and titled Agency, Substance Causation, and Top-Down Causation. It is also the longest chapter in the book, so a later post will also be about it.
Steward’s view has much in common with what’s called agent causationism, which holds that causation by agents is fundamental to any solution to the problem of free will. She doesn’t believe agent or substance causation is reducible to event causation. (She doesn’t say so explicitly, but her use of substance seems like that of Aristotle.) “The first and most crucial point to be made is that it is simply not correct to suppose that the ontology of most non-human causation is an event ontology. Causation by substances is utterly ubiquitous. Inanimate substances can cause things just as well as animate ones.” The idea seems to have become very prevalent in philosophy that where an inanimate substance may be said to cause something, it is always ‘really’ some event involving it that is the cause (p. 207).
Steward states three categories of cause – movers, makers-happen, and matterers.
“Roughly speaking, movers are things: usually substances, or collections o substances, although [ ] I would not want to rule out [ ] less familiar sorts of endurants, such as fields, might also be movers of a sort. They are such entities as stones and masses of air and water, animals and persons, as well as some of the smaller entities that go to make them up, like molecules and ions” (p. 212). One might object that fundamental physics may ultimately recognize no entities of the sort we generally suppose enduring things like this to be, but fundamental physics has little use for the concept of causation either. Movers are the primary doers of so-called ‘causal work’.
“Makers happen, roughly speaking, are the proper [Donald] Davidsonian events that trigger substances into action.” Often the event that triggers a mover into action is the impact of some other substance.
Matterers are facts. They are the causes we advert to by means of basically sentential expressions and which we link together with their effects by means of sentential connectives like ‘because’. For example, the match did not light because it was too damp.
There is no need for an agent causationist to deny that actions may have causes, but not all actions have a necessitating cause. If the latter were so, there would be no settling by agents.
The idea of a form of causation that is ‘top-down’ evidently exploits a metaphor of ascending levels. The relevant levels are relative, not absolute. There is no need to commit to monolithic divides across all of nature. For animals, for example, at the bottom there may be subatomic particles, moving up to atoms and molecules, then cells, tissues, and then organs, and finally top-level.