ABSTRACT
The decision to include Agr in the inventory of functional heads or to exclude it often seems to depend exclusively on theory-internal considerations. Chomsky (1995b), for example, proposes to dispense with Agr entirely, precisely because Agr has no content of its own. Tense is, along with v, the only conceptually necessary functional category in root clauses. However, this radically minimalist proposal does not provide much space to account for syntactic variation.
The primary goal of this chapter is to show that this tension between conceptual necessity and descriptive adequacy resolves once it is recognized that some functional categories, proxy categories, are not included in the initial numeration, but are created in the course of the syntactic computation. This hypothesis will lead to a restrictive theory of phrase structure only if the projection of these categories is narrowly constrained. Several Principles are introduced, aiming at further restricting the functioning of checking operations. A basic claim of the chapter is that the formal features of functional heads, if unchecked, must move in overt syntax, forcing the projection of an additional head, a proxy, immediately above the category whose features are being checked. Proxies exclusively serve to create new checking domains.
Once the notion of proxy head is introduced into phrase structure theory and the role of feature Fission in the fulfilling of the morpho-syntactic requirements of functional heads is recognized, it is possible to arrive at a highly restrictive theory of categories and movement.
