Peer-based Intelligibility

Accusations of unintelligibility are hard to deal with methodologically. They cannot amount to a direct argument against the view: after all, we cannot argue against something we do not understand. Unintelligibility considerations also have a certainad hominemflavor to them – if there are actual philosophers defending the views taken to be unintelligible, they are defending views which they do not understand. If you believe, as you should, that philosophers are not the kind of people that defend views they do not understand, at least not en masse, then you think that the fact that a reasonable number of philosophers defend a particular view is good evidence that the view is intelligible after all.

While this argument-form has its problems, I think that it is prima facie plausible. And Berto et al. use it to defend the phenomena of worldly opaque- ness. Here is what they say:

There are hyperintensional contexts that are not in any way ‘about representational features’ (see Nolan 2014), and counterfactuals may well be among these. Hyperintensionality without appeal to repre- sentation is invoked in many discussions of metaphysical ground- ing; [. . . ] The claim that hyperintensionality as such requires being about representational features would need serious support; and this Williamson does not offer. (Berto et al. 2017:9)

This reply rests on a confusion. What Williamson claims is unintelligible (or what I claim to be unintelligible on his behalf) is the phenomenon of worldly

opaqueness not worldly hyperintensionality. Berto et al. seem to think that these phenomena coincide:

That is, we take it that counterfactuals create hyperintensional con- texts, contexts in which substitutivity of identicals is not valid. (Berto et al. 2017:9)

Williamson (2017: 175) however, holds that this is “highly implau- sible”. The reason given there has two premises: that hyperinten- sionality occurs only in constructions that are “about representa- tional features” (that is, constructions that are broadly epistemic or intentional, like ‘It is a priori...’ or ‘Alice believes...’); and that counterfactuals are not about representational features in this way. (Berto et al. 2017:9)

But these phenomena do not coincide. In fact, none of the examples reviewed in Nolan (2014: Section 4) as instances of worldly hyperintensionality violate the substitutivity of identicals.6

And metaphysical grounding is also generally taken to be transparent. Claim- ing that the consensus on the grounding literature is that grounding is opaque would definitely be false. There is, however, one proponent of such a view, Wilson (2014). Wilson has been criticized in Bennett (2017: 3.2.2). It will be instructive to sketch the general lines of that debate in order to understand bet- ter what is at stake in ours. But first let me present a relatively uncontentious case of hyperintensionality without opaqueness to conclude the point that Berto et al.’s appeal to existing literature is misguided.

The example is taken from Williamson (2017: 210ff). Consider the relation A#B in which two sentences stand if and only if they express the same russelian proposition. A russelian proposition is, roughly, a structured entity which is expressed by declarative sentences and whose constituents are the objects and relations referred to and whose structure roughly mimics the syntactic structure of the sentence.7 The sentence “2+2=4” expresses the russelian proposition that can be represented by<[=],([+]([2],[2]),[4]>, which has as its constituents the numbers 2 and 4 and the relationsplus and identity. “#”, as defined above, is hyperintensional. “2+2=4” has the same intension as “2+3=5”, true at all possible worlds. But they do not express the same russelian proposition - one has the number three as a constituent and the other does not. But # is transparent. If you take any russelian proposition and substitute one of its constituents for an identical constituent, you get thesamerusselian proposition. This much should be enough to highlight the illegitimate inference from hyperintensionality to opaqueness.8

Let us now turn to the debate between Wilson and Bennet in the arena of metaphysical grounding. The discussion concerns the relation of being “more fundamental than”. It seems clear that such a relation must be irreflexive, in much the same way as the relation of “being taller than” must be irreflexive. But Wilson (2014: 573) thinks that there can be cases where: 1- a is more fundamental thanb; and 2- a=b. An example would be the case of identity- based physicalism. Such a physicalism would say that a mental state is identical to a physical state. But any physicalism must claim that the physical is more fundamental than the mental.

If all of the above is true, the relation of being “more fundamental than” had better be opaque. Otherwise, the physical would be more fundamental than itself (and so would the mental). For this reason, Wilson (2014: 573) postulates opaqueness for the “more fundamental than” relation.

Karen Bennett’s (2017: 43) reaction to Wilson is very much similar to the

6_{They are: explanation, essence, grounding, intrinsicality, property identities and disposi-}

tions.

7_{King (2007) is a very influential defense of this theory of propositions. Whether or not it}

is thecorrect theory of propositions is immaterial to the point I am making.

8_{But an instance of failure of substitutivity of identicals is, indeed, an instance of hyper-}

one Williamson has in relation to the non-vacuists. This should show that the issues we are dealing with in this chapter are general enough to be replicated in other debates in different areas.

Bennett’s main complaint is the following:

The claim that the predicate ‘more fundamental than’ creates an opaque context needs to be supplemented with a story about why it does so—a story, if you will, about the metaphysical underpinnings of the semantic phenomenon. (Bennett 2017: 44, my emphasis)

One explanation, which Bennett goes on to consider, is that representations are involved. But this cannot be the solution to this problem. The phenomenon of fundamentality is not a representational phenomenon. It has to do only with how things are in the world, not with the way we represent them to be. If the mental is identical with the physical then they are the samething. Bennett goes on to conclude:

Perhaps she has in mind a different explanation of, or metaphysical underpinning for, the putative opacity. But in the absence of one, it is not promising or plausible to retain reflexive [instances of “more fundamental than”]. (Bennett 2017: 45-6)

The objection is that the opacity in question must have some kind of meta- physical underpinning which must not be representation-based. Just postulat- ing opacity in a strictly worldly matter raises intelligibility worries. What is needed is a “story [. . . ] about the metaphysical underpinnings of the semantic phenomenon”. And that is exactly what is required of the non-vacuist which thinks the counterfactuals are opaque.

In the next section, we will consider a way in which Berto et al. try to provide one and see why it should be found wanting.