barrier (n.)

A term used in GOVERNMENT-BINDING THEORY to refer to categories whose boundaries restrict certain phenomena. A barrier is a NODE which blocks the syntactic processes of MOVEMENT and GOVERNMENT: one barrier blocks government; two barriers block movement. The principle that movement cannot cross more than one barrier is known as SUBJACENCY. A is considered to be an (inherent) barrier for B if A is a ‘blocking category’ for B: to be a blocking category, A must not be THETA-marked by a LEXICAL (L) category, and A must dominate B. Anything can be a barrier, apart from IP (INFLECTION-phrase). Other nodes can also become barriers for B if they dominate a blocking category for B (the INHERITANCE barrier) or if they dominate the nearest governor of B (the ‘MINIMALITY condition’). The notion became increasingly important in SYNTACTIC theory following the publication of Noam Chomsky’s Barriers (1986). Barriers are also encountered in PHONOLOGY, where they refer to any unit (e.g. a BOUNDARY SYMBOL, a SEGMENT) within a STRING which blocks the application of a phonological RULE to that string.