Symmetry, Shared Labels and Movement in Syntax

What is the trigger for displacement phenomena in natural language syntax? And how can constraints on syntactic movement be derived from interface conditions and so-called Third Factor principles? Within the Minimalist Program a standard answer to the first question is that it is driven by morphosyntactic features. This monograph challenges that view and suggests that the role of features in driving syntactic computation has been overestimated. Instead it proposes that "labeling" -- the detectio