Cosubstitution, Derivational Locality, and Quantifier Scope

Quantifier scope challenges the mantra of Tree Adjoining Grammar (TAG) that all syntactic dependencies are local once syntactic recursion has been factored out. The reason is that on current TAG analyses, a quantifier and the furthest reaches of its scope domain are in general not part of any (unicomponent) elementary tree. In this paper, I consider a novel basic TAG operation called COSUBSTITUTION. In normal substitution, the root of one tree (the argument) replaces a matching non-terminal on the frontier of another tree (the functor). In cosubstitution, the syntactic result is the same, leaving weak and strong generative capacity unchanged, but the derivational and semantic roles are reversed: the embedded subtree is viewed as the functor, and the embedding matrix is viewed as its semantic argument, i.e., as its nuclear scope. On this view, a quantifier taking scope amounts to entering a derivation at the exact moment that its nuclear scope has been constructed. Thus the relationship of a quantifier and its scope is constrained by DERIVATIONAL LOCALITY rather than by elementary-tree locality.