Some Test Cases

This much of Horgan’s characterisation also seems promising as an answer to our

‘characterisation’ question, but it isn’t the end of the story either. We’re now going to look at a set of ‘test cases’ which show some details that the accounts we’ve seen so far either get wrong, or fail to address fully, and which give us a benchmark against which we can test other proposals.

The first case is the expression ‘early thirties’. This case is raised in Smith (2008, 156) and Weatherson (2010, 81). The problem here is that someone starts being in their early thirties the moment they become thirty (which seems to be a precise matter), while the expression ‘early thirties’ is presumably vague — when does someone stop being in their early thirties? Yet Horgan’s proposal (as stated so far) classifies it as precise, since competent speakers with enough information about people’s ages will

draw a sharp boundary between those to whom ‘early thirties’ applies and those to whom it does not on the basis of a small change in age.

Likewise, competent speakers would presumably not by default take ‘early thirties’

to be tolerant, and so Eklund’s characterisation as stated so far seems to make the wrong prediction for ‘early thirties’. Now Eklund does adapt his view in light of this kind of case to say that, for a term to be vague, speakers must be disposed to take it to be tolerant ‘somewhere along its parameter of application’ (2005, 49, his emphasis). It’s not immediately clear what exactly this amounts to — what exactly does a speaker need to believe to believe that a term is tolerant somewhere along its parameter of application? In the case of ‘early thirties’, for example, it can’t be that making someone a day older doesn’t affect whether they’re in their early thirties, because making a 29 year old a day older can sometimes have an effect on that. Maybe, then, it’s that making someone a day older can’t take them from being in their early thirties to not being in their early thirties. But this isn’t the same thing as saying that ‘early thirties’ is tolerant somewhere along its parameter of application — it’s to specify exactly where along its parameter of application it is tolerant.

Perhaps a way to spell out the claim that a term is tolerant somewhere along its parameter of application would be to say that a certain disjunction is true: in the case of ‘early thirties’, for example, we could say that it’s tolerant in this respect if either making someone a day older can’t take them from being in their early thirties to not being in their early thirties or making someone a day older can’t take them from not being in their early thirties to being in their early thirties. In this case, the first disjunct is the one that Eklund claims to be the one that competent speakers would by default take to be true. This seems to work by Eklund’s lights, though in the next section we’ll see a way in which we can eliminate the need to use a disjunction by appealing to something more general.

The second test case is the artificial predicate ‘child*’. Recall that someone is a child* if they’re younger than 17, and not a child* if they’re older than 18, and so by stipulation it’s indeterminate whether those who are between 17 and 18 are children*.

Eklund’s characterisation seems to get this one correct: competent speakers wouldn’t by default take ‘child*’ to be tolerant (since it’s at best unclear whether someone who turns 17 stops being a child* at that moment), and so it comes out as precise. It’s less clear what Horgan’s view (as stated, at least) says about this case; really we need to know what counts as a ‘polar opposite’ verdict before we can say whether compet-ent speakers would apply polar opposite verdicts to marginally differcompet-ent cases when it comes to ‘child*’. It seems inappropriate to say, for example, that the sentences

‘someone who’s a moment under 17 is a child*’ and ‘someone who’s exactly 17 is a child*’ go from true to false, or perhaps even from true to not true, since the status of the latter is by stipulation indeterminate. Still, it would be appropriate for someone to assert that between these two sentences there is a clear change from determinacy of status to indeterminacy. If Horgan’s notion of a ‘polar verdict’ allows for this, then Horgan’s characterisation correctly predicts that ‘child*’ is precise; it’s just not clear whether it does. In any case, whatever account we arrive at in the end, we should make sure that it predicts that ‘child*’ is precise.

The third test case is actually a set of cases. We need to ask: what does the correct account say about different borderline categories? Supposing that ‘green’ is vague, does the account predict that ‘borderline green’ is vague? ‘Borderline borderline green’?

How far does this go, if at all? I raise this last set of cases not necessarily as a set of cases about which either Eklund or Horgan gets things wrong; rather I raise it as something which any account needs to have a defensible answer to.