Abstract
Current theories place very mild constraints on possible diachronic changes, something at odds with the trivial observation that actual, “language change” represents a tiny fraction of the variation made a priori available by Universal Grammar. Much recent work in diachronic syntax has actually been guided by the aim of describing changes (e.g., parameter resetting), rather than by concerns of genuine explanation. Here I suggest a radically different viewpoint (the Inertial, Theory of diachronic syntax), namely, that syntactic change not provably due to interference should not occur at all as a primitive-that is, unless forced by changes in the phonology, the semantics, or the lexicon, perhaps ultimately by interface or grammar-external pressures, in line with the minimalist enterprise in synchronic linguistics. I concentrate on a single case, the etymology of Modern French chez, showing howthe proposed approach attains a high degree of explanatory adequacy.