Theoretical Comparative Syntax

4   Parameters and optionality

Chomsky (1991b) proposes general principles of economy that require derivations and representations to be minimal in cost. To provide the economy principles with full empirical content, it is of course necessary to characterize precisely the notion of “cost” in a grammar. Among other things, the status of optionality, particularly the status of optional movement, has been quite unclear under the general economy approach, which “tends to eliminate the possibility of optionality in derivation” (Chomsky 1991b: 433). Under the economy approach, “choice points will be permissible only if the resulting derivations are all minimal in cost” (p. 433). It then follows that an optional rule is allowed only if its application ...