Editing Minimalist program (section)

====Phase impenetrability condition (PIC)====

Movement of a constituent out of a phase is (in the general case) only permitted if the constituent has first moved to the left edge of the phase (XP).

The edge of a head X is defined as the residue outside of X', in either specifier of X and adjuncts to XP.<ref>{{Cite book|last=Chomsky|first=Noam|url=https://books.google.com/books?id=E-IbAQAAIAAJ|title=Derivation by Phase|date=1999|publisher=MIT, Department of Linguistics|language=en}}</ref>

English successive cyclic wh-movement obeys the PIC.<ref name=":0" /> Sentence (7) has two phases: ''v''P and CP. Relative to the application of movement, ''who'' moves from the (lower) ''v''P phase to the (higher) CP phase in two steps:

*Step 1: '''''who''''' moves from the complement position of VP to the left edge of ''v''P, and the EPP feature of the verb forces movement of '''''who''''' to the edge of vP.
* Step 2: '''''who'''''  moves from the left edge of the lower ''v''P phase to the specifier of the (higher) CP phase.

 (7)  [<sub>CP</sub> '''''Who''' did you'' [<sub>vP</sub> ''see'' <s>who</s>]]?

 {| class="wikitable"
 |<!--col1-->[[File:Phasal_Movement_Syntax_tree-_step_1.png|300x300px]]
 |<!--col2-->[[File:Phasal_movement_tree-_step_1.png|300x300px]]
 |-
 |<!--col1-->Step 1: wh-phrase moves to edge of vP phase
 |<!--col2-->Step 2: wh-phrase moves to edge of CP phase
 |}