Projection Principle

Projection Principle is a principle which says that


 * 1)  representations at each level of representation are projections of the features of lexical items, notably their subcategorization features, and that
 * 2) if F is a lexical feature, it is projected at each syntactic level of representation (D-structure, S-structure,  Logical Form).

The Projection Principle entails that sentence (i) cannot have the structure in (ii).

(i) I believe him to be a fool (ii)  I believe [NP him] [S to be a fool]

The NP him is the subject of the embedded sentence at the level of D-structure, so it has to be analyzed as its subject at all syntactic levels of representation, even though it has objective case. See also Extended Projection Principle.

Links
Utrecht Lexicon of Linguistics