To which extent are counterfactuals context-dependent? Lewis suggested that we can do without a systematic dependence on context by combining an invariant similarity relation with a variably strict analysis of counterfactuals. Recently, this approach has been challenged partly by drawing attention to the phenomenon of reversed Sobel sequences: sometimes it seems as if the order in which two counterfactuals are uttered makes for a difference in truth-value. Philosophers who take this phenomenon to be semantic in nature have reacted to it by allowing the similarity relation to vary from context to context (for instance, have a look at von Fintel’s semantics for counterfactuals, which you can find here). In this note, I’d like to challenge the semantic analysis of reversed Sobel sequences by arguing that it does not square well with a plausible link between “would”-counterfactuals and “might”-counterfactuals.

Here is the phenomenon. In an initial context, the counterfactual

(1) If she had been at the concert, she would have seen Mick Jagger

may be truly asserted, or so it is assumed. Subsequently, the counterfactual

(2) If she had been at the concert and got stuck behind a group of tall people, she would not have seen Mick Jagger

may be accepted, too. All this is to be expected on Lewis’s account: strengthening the antecedent is not a valid rule of inference. But now suppose that (1) and (2) are uttered in reversed order: it seems that asserting (1) after (2) is not o.k. There is something odd about saying

(3) If she had been at the concert and got stuck behind a group of tall people, she would not have seen Mick Jagger, but if she had been at the concert, she would have seen Mick Jagger.

So, can the order in which these counterfactuals are uttered affect their truth-values?

Posted by Moritz.

There is a plausible link between “would”-counterfactuals and “might”-counterfactuals. We can capture it with the following principle:

(M) A counterfactual of the form “If *A* had been the case, *B* would have been the case” is assertable just in case “If *A* had been the case, *B* might not have been the case” is rejectable (if *A* is taken to be possible).

On Lewis’s account, there is a straightforward explanation for this: the former “would”-counterfactuals are true just in case the latter “might”-counterfactuals are false. To put it another way, “might”-counterfactuals are duals of the corresponding “would”-counterfactuals.

Now, in order for the phenomenon of reversing Sobel sequences to get off the ground, one really needs the fact that (1) is assertable in the initial context. Given (M), this requires that

(4) If she had been at the concert, she might not have seen Mick Jagger (because she might have been stuck behind a group of tall people)

can be rejected. But in the circumstances most naturally associated with the example, (4) cannot be rejected. This suggests that (1) wasn’t really assertable in the first place. Perhaps it seemed o.k. to assert it because one did not think of the possibility that she might have got stuck behind tall people. Plausibly, if the standards of assertability are low, a counterfactuals passes these standards if most of the close antecedent-worlds are consequent-worlds. But once certain possibilities are mentioned, the standards of assertability are raised, and beeing close to the truth isn’t good enough any longer.

Note that the picture changes if (4) can be rejected. Suppose it is known that there weren’t any tall people around at the concert. Then (4) can indeed be rejected and (1) is indeed fully assertable in the initial context. But then it doesn’t seem clear to me that (3) would not be o.k. Perhaps the following utterance would lack a decisive point, but from a semantic perspective it seems fine:

(3′) If she had been at the concert and got stuck behind a group of tall people, she would not have seen Mick Jagger, but since there weren’t any tall people around at the concert, if she had been at the concert, she would have seen Mick Jagger.

Kenny(00:57:35) :Sarah Moss (a graduate student at MIT) has been arguing something similar. I’m not sure if she has a full paper up on her website at the moment, or if she’s only given talks. I’m sure she’d be interested in discussing her pragmatic account though, if you e-mail her!

moritzschulz(09:50:32) :Hi Kenny,

thanks for pointing that out! The paper is indeed on her website, one can find it here.

wo(12:29:55) :I’m worried that your argument from (4) to the falsehood of (1) generalizes too far. In fact, this is just the argument Al Hajek uses to support his claim that almost all counterfactuals ever uttered are false (in his paper “Most counterfactuals are false”).

moritzschulz(15:17:53) :Hi Wo,

that’s an important point. I thought, though, that I only need something weaker: a counterfactual and the corresponding “might”-counterfactual (which would be its dual if Lewis is right) are not jointly assertable. At least prima facie, this is compatible with the idea that the “would”-counterfactual may nevertheless be true. Compare: a present tense “Might not A”-statement and the corresponding “Will A”-statement are not jointly assertable, even though both of them may be true together (given standard semantics).

So, I agree that the argument is kind of playing with fire, but perhaps I don’t get burned.