Implementing Boundaries

Let me now give some more speci c, albeit still rather general reasons to think that none of the proposals can be made to work in a way that is compatible with the key tenets of semanticism. In this sub- section, that is, I am going to assume that some sort of case has been

_{With regard toi), the semanticist might be tempted to appeal to some weaker notion of cat-}

egory, perhaps de ned by means of the ‘partial signi cation’ relations suggested in Field (1973: 202)—items in each category would refer to tokens of arangeof candidate types, rather than of a unique type. is would amount to a species of sense-enumeration strategy (type-enumeration, in this case), and it would suffer from the problems which I discuss in the next two chapters. Nor would it help to appeal to the notion of arbitrary object for the type, as per Fine (1983), for again we lack criteria for associating a given range of objects with each type. As forii), see fn. 144, p. 46, and the last bullet point on the same page.

_{is aspect of CC is explicitly spelled out in Chomsky (1966: 59).}

_{To reiterate: those tenets include a commitment to CC, EPoCU, MDP and UaKTC, plus the}

What Compositionality Could Not Be |  made to justify a speci c choice of categories. I argue that no such choice would be implementable.

Here’s why:

• e most natural way to think of semantic categories is in terms of equivalence classes closed under substitution. is how- ever gets things intuitively wrong. First, expressions can be very unstable under language expansion (new expressions cre- ate new contexts where substitutivityfor the old categoriesmay fail). Secondly, the intersubstitutivity criterion would sep- arate expressions that intuitively belong to the same category (classic case: the ‘eat/devour’ pair). _{Semantic categories de-} ned by closure under substitution, then, whatever their prove- nance and grounding, would end up being either impossibly ne-grained (in all likelihood: singleton classes, for we could always come up with a linguistic context in which intersubsti- tutivity fails) or drawn only relative to a given language strictly conceived (language expansion would not be conservative with respect to the class of semantic categories, that is). is of course would make CC completely uninteresting since catego- rial features would only be determinedaer observing an ex- pression’s behaviour underallpossible embedments, including those generated bynewwords added to the original language. • It is impossible to draw the boundaries of semantic categories without robust appeal to metaphysics, for we need identity cri- teria for what counts as e.g. an individual (andpari passufor all other categories) before we can specify the range of signi cance of a given predicate. _{e same is true for all other features} spelling out the various subcategorisation restrictions. In short, the required separation between semantics and metaphysics is simply not available. And it would be no escape route for the semanticist toassumesome such drawing of boundaries is pos- sible. As I have said already:thatis precisely the point at issue. If

_{See Hodges (2005: 54).} _{Hodges (1998: 11).}

_{Perhaps this was what Quine (1953b: 155) had in mind when criticising Strawson (1952) and}

Russell by noting “the obscurity of the notion of category involved” in type theory and the diffi- culties both in settling and implementing categorical restrictions. One might of course accept that

gradienceis a feature of categories (see e.g. Muysken 2008: 3ff.), but the problem recurs: what dis- ciplines the relevant aspects of categorial gradience? It might be objected that I am here taking ‘language’ in too formal a sense (adding new expressions gives rise to new languages). Quite so. But this is exactly what the semanticist commitment to PoC entails.

 | Chapter 

it proves to be metaphysically impossible to draw xed bound- aries for our categories (say, because our concepts are ineradi- cably vague), then a compositional meaning theory will have to be a very different beast from what is standardly assumed; its very structure, and the way in which it spells out the normative constraints on performance (in terms ofhowthe theory mod- els our competence) would have to be radically re-thought from the ground up.

• Finally, and most seriously, and even assuming that the two difficulties just listed can be overcome, the need to implement selectional restrictions to rule out nonsense and thus preserve PoCU lands the semanticist straight into the jaws of my SD I, for a lexicon that would be fully equipped topredictthe emer- gence of NS across the board would be unlearnable. It would be, that is, too complex for us to master, for the simple reason that the range of contextual embedments that would need to be considered fully to predict when NS would arise has cardinality strictly greater thanℵ0. e purported explanation of how nite minds can encompass in nite (linguistic) totalities thus ounders under pressure from nonsense.

I conclude that the only nonsense-busting answer open to the seman- ticist at this point in the dialectic is one whose implementation would exceed our computational abilities.

_{In contrast to my view of these matters, Larson and Segal (1995: 46) argue that a theory of se-}

mantic aberrancy lies “outside semantics proper”. ey seem to have forgotten that 43 pages earlier they’d said that semantics should tell us about nonsensical anomaliesand their sources. Szabó (2000: 40) makes the equally astonishing remark that “as far as the semantics is concerned” liar sentences and Chomsky sentences “do not qualify as genuine sentences” at all. Cappelen and Lepore (2005a: ch. 11) also argue against con ating semantics and metaphysics.

_{Indeed, Tarski (1935: 216) himself had asked whether before drawing categorial boundaries}

we need to checkallsentential embeddings for substitutivity failure or whether one case would be enough to determine the pro le of a given semantic category. Consider now the following startling admission by two leading Chomskyans: “Ideally, knowing the thematic structure of a given verb is akin to knowingeverything there is to knowabout the sorts of constructions where this verb can appear” (Lasnik and Uriagereka 2005: 6-7), my emphasis (see also Chomsky 1981: 31 and Collins 2003: 428). e point is: how much work can ‘ideally’ be doing in an explanation ofour

competence? Chomsky (1972a: 146) had spoken more generically of lexical entries as containing “a complex account of conceptual structure, nuance, presuppositions.” e computational costs of such an account were however le unexplored. Note also that Lasnik and Uriagereka (2005: 4) blithely concede that wemaydiscover “a new subcategorization frame” for a verb (roughly, a sentential embedment where a new thematic role isdisclosed); all we need to do in those cases, we are told, is “add it to the lexicon.” Again, this may preserveex post factoPoC, but it certainly does not address the CC puzzle.

What Compositionality Could Not Be |  e upshot is that the attempt to salvage the full generality of EPoCU from the problems posed by nonsense requires the imposi- tion of restrictions on meaningful derivations that force the semanti- cist to sacri ce learnability (that’s my SD I again, and that shows once more that PoC and CC are incompatible requirements on a seman- tics).

If I am right about all this, the only other option for the semanticist is to argue that wedounderstand nonsense, that the meaning of NS is compositionally determined (and compositionally understood) just as in normal cases. is would clearly preserve the desired CC/PoC connection. But there are other costs involved (it’s the other horn of my SD II aer all) and in the next section I try to assess them.