On certain differences between noun phrases and clauses

Along with the noted similarities that have prompted much important study in the development of the theory of phrase structure and movement, nouns and verbs (and their projections) exhibit remarkable differences. These differences have often been neglected or otherwise discredited in favor of the similarities that have been a target for novel proposals regarding the internal structures of noun phrases and clauses. This paper tries to pin down the locus of the differences, and identifies the fundamental difference between noun phrases and clauses as the fact that noun phrases (nominal expressions) have a singlelayered internal structure having a single phase and are completed (or “closed”) in terms of licensing of internal elements, whereas clauses have a double-layered internal structure with two internal phases one of which (vP) is not completed (or “open”) in the sense that outside probes (namely, C and C-T) play a role in determining the inner workings of vP. The paper argues in a preliminary form that from this fundamental difference (which itself seems to be rooted in considerations of the C-I interface, i.e., clauses are propositions while nominal expressions are typically arguments), various syntactic differences between the two classes of categories, particularly those with respect to A-movement and A’-movement, naturally follow.