Final and efficient causation

It is sometimes said that:

1. One can have p explain q and q explain p when the types of explanation are different.

I think (1) is mistaken, but in this post I want to focus not on arguing against (1), but simply on arguing against one particular and fairly common form of argument for (1):

2. In cases of Aristotelian final causation, it typically happens that y is a final cause of its own efficient cause.

3. If y is a final cause of x, then that y occurred finally explains that x occurred.

4. If x is an efficient cause of y, then that x occurred efficiently explains that y occurred.

5. So, it’s possible to have p explain q and q explain p when the types of explanation are final and efficient, respectively.

I want to argue that this argument fails (bracketing the interpretive question whether Aristotle or Aquinas accepts its premises).

First, explanation is factive: if p explains q, then both p and q are true. This is because explanations provide correct answers to why questions, and a false answer isn’t correct. But final explanations are not factive. I can offer an argument in order to convince you and yet fail to convince you. (Indeed, perhaps this post is an example.) Therefore, (3) is not always true. That doesn’t show that (3) is false in the case that the argument needs. But it is plausible that an action that fails for extrinsic reasons has exactly the same explanation as a successful action. The failed action cannot be explained by its achieving its goal, since it doesn’t achieve its goal. Therefore, the successful action cannot be explained in terms of its achieving its goal, either.

Second, efficient causation is a relation between tokens. If I turn on the lights in order to alert the burglars, then my token turning-on-the-lights is the efficient cause of the token alerting-the-burglars. But final causation is not a relation between tokens. For suppose that I fail to alert the burglars, say because the burglars are blindfolded (they were challenged to rob me blind, and parsed that phrase wrong) and don’t see the lights. Then there are infinitely many possible tokens of the alerting-the-burglars type any one of which would pretty much equally well serve my goals. For instance, I could alert the burglars at 10:44:22.001, at 10:44:22.002, etc. In the case of action failure, no one of these tokens can be distinguished as “the final cause”, the token I am aiming at. Indeed, if one particular possible token a₀ were the final cause, then if I happened to produce another token, say a₇, my action would have been a failure—which is absurd. Thus, either all the infinitely many possible tokens serve as the final causes of the action or none of them do. It seems wrong to say that there are infinitely many final causes of the action, so none of the tokens is.

Given that explanation of the failed action is the same as of the successful action, it follows that even in the successful case, none of the tokens provides the final cause.

Therefore, we should see final causation as a relation between a type, say alerting the burglars at some time or other near 10:44:22, and a token, say my particular turning on of the lights. But if so, then (2) is false, for it is false that in the successful case the same things are related by final and efficient causation: the final causation relates the outcome type with a productive token and efficient causation relates the productive token with the outcome token.

As I said, this doesn’t show that (1) is false, but it does show that efficient and final explanation do not provide a case of (1).

Acknowledgments: I am grateful to Tim Pawl for discussion of these questions.