What the PCC tells us about “abstract” agreement, head movement, and locality

Based on the cross- and intra-linguistic distribution of Person Case Constraint (PCC) effects, this paper shows that there can be no agreement in ϕ -features ( PERSON, NUMBER, GENDER/NOUN-CLASS ) which systematically lacks a morpho-phonological footprint. That is, there is no such thing as “abstract” ϕ -agreement, null across the entire paradigm. Applying the same diagnostic to instances of clitic doubling, we see that these do involve syntactic agreement. This cannot be because clitic doubling is agreement; it behaves like movement (and unlike agreement) in a variety of respects. Nor can this be because clitic doubling, qua movement, is contingent on prior agreement—since the claim that all movement depends on prior agreement is demonstrably false. Clitic doubling requires prior agreement because it is an instance of non-local head movement, and movement of X 0 to Y 0 always requires a prior syntactic relationship between Y 0 and XP. In local head movement (the kind that is already permitted under the Head Movement Constraint), this requirement is trivially satisfied by (c-)selection. But in non-local cases, agreement must fill this role.