Binding (linguistics) - Binding of Nominals Versus Operator-variable Binding

Binding of Nominals Versus Operator-variable Binding

Generative syntax distinguishes two kinds of binding. The first concerns nouns and the binding conditions discussed above: this is referred to as A-binding. The second concerns binding of another kind, a kind of logical binding known as operator-variable binding, or A'-binding.

Operator-variable binding is the formal mechanism employed to explain the syntax of interrogatives (questions), topicalization, as well as relative clauses, and other related language constructions.

In essence, operator-variable binding provides a way for an individual entity (or entities) to be picked out from a set of entities. Since this is a very abstract definition, an illustration will be helpful. Look at the two examples below. The first is a statement, and the second is a question derived from the statement.

(1) Smoltz hit Rodriguez with the baseball.
(2) Whom did Smoltz hit with the baseball?

Notice in the question (2), whom, which corresponds to the object of the verb hit, appears at the left of the sentence, not in the position marked, which is where the object appears in the statement.

The position marked by is linked to, (or bound by), the question word whom. Whom is the operator, denoting a set of individuals, and the spot is the variable, while the range of the operator is, in essence, limited to those people whom Smoltz might have hit (with the baseball). Notice that, since (2) is a question, it would not be quite correct to say that whom and Rodriguez refer to the same thing, since it is also possible that John Smoltz hit other people (with the baseball) as well.

The names A-binding and A'-binding come from the idea of A-levels and A'-levels, which distinguish arguments (required elements, such as subjects, objects, etc.) from non-arguments, such as elements which may have been arguments, but have moved "beyond" to become something else in addition, such as a question word; also elements which are peripheral, such as certain kinds of modifiers.

Thus, in the example (1) above, Smoltz and Rodriguez are A-level elements, since they are arguments of the verb hit (hit requires both someone/something that does the hitting, and someone/something that was hit. A'-level elements are question word whom in (2), as well as with the baseball. Whom was once an argument of hit, but has moved to the left to satisfy a rule in English that (more-or-less) requires question words to move to the left. The element with the baseball is not an argument of anything, since removing it would still result in a grammatical sentence (in the sense of syntactic theory), whereas removing either Smoltz or Rodriguez would not.