One point raised in Chomsky’s Minimalist Program (MP) (1995), which had earlier antecedents in the literature (e.g., Pesetsky 1982), is the theoretical condition that paths (its ‘trace’ pathway) of movement cannot overlap (can’t cross one another), labeled as the Path Containment Condition. In more recent terminology, this same condition is referred to as the Edge Constraint. Let’s consider how these two similar conditions on movement work when considering ‘wh’-subjects.