Heim on Comparative Clauses

Metaphysical eternalists occasionally offer presentists the following challenge: if only present things exist, how do we account for the truth of claims of the following sort:

-Al Gore is taller than almost any ancient politician
-Russell was smarter than most philosophers of his generation.

The alleged problem for the presentist is that claims like these seem to ascribe cross-time relations. But no relation can be instantiated by objects that do not exist.

As it turns out, however, if Irene Heim's recent theory of comparative adjectives is correct, comparative claims pose no problem for presentism. Heim begins with claims of the following sort:

-John is taller than every girl
-John is taller than one of the girls

As Richard Larson (1988) argues, such claims can be dealt with by positing that (i) the quantified noun phrase moves to a wide-scope position and (ii) the comparative expression 'taller than' combines with two type e expressions (i.e., variables or referring terms). But a similar strategy is unavailable for claims of the following sort:

-John is taller than every girl is.
-John is taller than one of the girls is.

The initially tempting hypothesis that the quantified noun phrases scope out of the 'than'-clauses is extremely implausible, given what we know about the sort of movement quantified noun phrases undergo (quantified noun phrases do not normally scope out of relative clauses, etc.) Moreover, Heim argues, even if quantified noun phrases could scope out of 'than'-clauses, adverbs of quantification, modal expressions and floated quantifiers can't possibly do that. Out-of-'than'-clause accounts of comparatives are thus unable to account for claims of the following sort (from Heim):

-The suit cost more than they had each paid in taxes.
-It is warmer here today than it usually is in New Brunswick.
-It is warmer today than it might be tomorrow.
-George is richer than his father was and his son will be.

After considering some traditional analyses of comparatives, Heim then offers a theory where comparatives ascribe relations between what she calls "degrees" (i.e., abstract entities like heights, weights, etc.). To account for quantifier scopes, Heim suggests that there are semantically vacuouos 'wh'-items in the sentence structure of comparative claims. 'John is taller than every girl is' is thus of the following form:

[wh5[every girl is t5]]4 [John is taller than t4]

'Every girl is wh', where 'wh' is a semantically vacuous 'wh'-item, scopes out of the comparative clause, and the 'wh'-item raises to a wide-scope position. The truth-condition for this sentence is: for every girl x, John's height is greater than x's height.

From a semanticist's point of view, Heim's hypothesis is interesting because it makes the right predictions in nearly every case. From a metaphysician's point of view, her theory is interesting because it makes presentism look less unattractive. Consider:

-Al Gore is taller than almost any ancient politician ever was

Heim's theory predicts that this sentence is of the following form.

[wh5[almost any ancient politician was t5]]4 [Gore is taller than t4]

Assuming the past tense takes wide scope over the quantified noun phrase 'almost any ancient politician', we get the following truth-condition: it was the case that, for almost any ancient philosopher x, Gore's height is greater than x's height. As this analysis incurs no commitments to the existence of non-present individuals, presentists can happily embrace it.

Reference:
Larson, R. (1988), "Scope and Comparatives", Linguistics and Philosophy.