ject matter.  It may help if I quote Chomsky again:

| In linguistic theory, we face the problem of constructing
| this system of levels in an abstract manner, in such a way
| that a simple grammar will result when this complex of abstract
| structures is given an interpretation in actual linguistic material.
|
| Since higher levels are not literally constructed out of lower ones,
| in this view, we are quite free to construct levels of a high degree
| interdependence, i.e., with heavy conditions of compati