# Lewis on causation and biff

I’ve been reading Lewis’s late papers on causation, and I can’t figure out how to make consistent some of the things he says in ‘Void and Object’ and some of the things he says in ‘Causation as Influence’. Here is one of the objections to applying the Canberra plan to causation that he offers in ‘Causation as Influence’. (Page numbers are from the versions of the papers in Causation and Counterfactuals.)

The problem of the many diverse actual causal mechanisms, or more generally of many diverse mechanisms coexisting in any one world, is still with us. If causation is, one might be, wildly disjunctive, we need to know what unifies the disjunction. For one thing the thug platitudes tell us is that causation is one thing, common to the many causal mechanisms. (76)

But in Void and Object, Willis says that the Canberra plan approach is a good approach to determining what biff is, and he makes the following speculations about what kind of thing biff will turn out to be.

Myself, I’d like to think that the actual occupant of the biff-role is Humean-supervenient, physical, and at least fairly natural; but nothing else I shall say here is premised on that hope. (284)

Here’s the problem. There are, as Lewis says in Causation as Influence, many actually existing causal mechanisms. They don’t seem to have a lot in common. So biff looks like it should be pretty disjunctive. Yet Lewis says, or at least hopes, but it will turn out to be fairly natural. I don’t see how both those things can be true.

## 3 Replies to “Lewis on causation and biff”

1. I thought Lewis was explicit in “Void and Object” that biff is not the same as causation. Are you saying that’s not the right way to read him?

Given that biff != causation, can we make sense of what Lewis says in the following way:

(a) The Canberra Plan won’t work for causation as a whole since causation as a whole is disjunctive and it is a core piece of the folk notion of causation that causation is not disjunctive.

(b) The Canberra Plan might work for the sub-species of causation that Lewis calls biff, since biff is not disjunctive and the folk might have coherent intuitions about biff, even if they don’t have a distinct label for it.

Do you think that works? If not, why not?

2. Causation isn’t biff, but what I don’t understand is why the plurality of causal mechanisms argument doesn’t show that biff is disjunctive.

So I think (b) is what Lewis says in Void and Object, but it is inconsistent with what he says in Causation as Influence.

3. My impression was that Lewis was concerned with the difference between connective and disconnective mechanisms. That is, the whole issue came down to causation by absence: when there are absences, there cannot be a causal “relation.”

For connective mechanisms, causation gets to be some relation or other. In that case, one can at least hold out hope that causation is non-disjunctive — that causation is a single relation. In the quotation you give in your post, it seems to me that Lewis is simply hoping that whenever there is a causal relation, it is the same relation underneath the particular mechanical details.

For me it comes down to this: does the mechanical plurality make any difference to the metaphysical unity of causation. For disconnective mechanisms in an event-based theory of causation, the answer is “Yes.” Are there mechanical details that would matter for the metaphysics in the case of connective mechanisms? You seem to think that there are, but I don’t see it yet. Could you say a bit more about what you think is problematic here?

(Incidentally, it looks like that passage is in Causation and Counterfactuals but not in Lewis’ 2000 paper with the same title in the Journal of Philosophy. I only have the latter on hand, though, so I can’t check what’s going on around the passage in the book right now.)