RADICAL ARGUMENT DROP VIEWED THROUGH PARAMETRIC VARIATION: Parametric Variation: Null Subjects in Minimalist Theory by Theresa Biberauer, Anders Holmberg, Ian Roberts and Michelle Sheehan, Cambridge University Press, Cambridge, 2010, vi+368pp

The present article attempts to summarize the major achievements advanced in Parametric Variation by Biberauer, Holmberg, Roberts and Sheehan on the one hand, and to develop some central ideas proposed in the volume to account for a novel generalization about radical argument drop, on the other. The generalization is proposed that every language that allows argument ellipsis allows pro. As the generalization itself implies, it is argued that radical argument drop is not a uniform phenomenon. Rather it consists of pro and elided arguments.