Parameter Theory and Parametric Comparison

The Parametric Comparison Method (PCM) is a comparative procedure designed to investigate phylogenetic relationships between languages. It is based on the assumption that (syntactic) parameter theories may provide a radically new and mathematically reliable system or studying the historical evolution and classification of languages into families, and that the synchronic and the historical study of formal grammar can be ultimately related within a unified approach, made available precisely by the rise of parametric linguistics. This chapter shows that parameter analyses can be successfully used to attain historical adequacy: the fact that parametric classifications largely match the established families demonstrates the possibility of reconstructing history through syntactic parameters, which appear to carry a chronologically deep, statistically robust, and prevailingly vertical historical signal. In addition, parameter systems as theories of grammatical variation and its implicational structure receive novel support precisely from their success with historical issues: the correctness of the phylogenetic hypotheses made by the PCM further confirms the universal theory of parameters, constraints, and implications subsumed into it.