Editing Government and binding theory (section)

==Binding==
[[Binding (linguistics)|Binding]] can be defined as follows:

* An element α binds an element β if and only if α [[c-command]]s β, and α and β corefer.

Consider the sentence "John<sub>i</sub> saw his<sub>i</sub> mother", which is diagrammed below using simple [[phrase structure rules|phrase structure trees]].

[[Image:Government and Binding Theory basic tree.png]]

The NP "John" c-commands "his" because the first parent of the NP, S, contains "his".  "John" and "his" are also coreferential (they refer to the same person), therefore "John" binds "his".

On the other hand, in the ungrammatical sentence "*The mother of John<sub>i</sub> likes himself<sub>i</sub>", "John" does not c-command "himself", so they have no binding relationship despite the fact that they corefer.

[[Image:the mother of John.png]]

The importance of binding is shown in the grammaticality or ungrammaticality of the following sentences:

# <nowiki>*</nowiki>John<sub>i</sub> saw him<sub>i</sub>.
# John<sub>i</sub> saw himself<sub>i</sub>.
# <nowiki>*</nowiki>Himself<sub>i</sub> saw John<sub>i</sub>. 
# <nowiki>*</nowiki>John<sub>i</sub> saw John<sub>i</sub>.

Binding is used, along with particular binding principles, to explain the ungrammaticality of statements 1, 3, and 4. The applicable rules are called Binding Principle A, Binding Principle B, and Binding Principle C.

*'''Principle A:''' an anaphor (reflexive or reciprocal, such as "each other") must be bound in its governing category (roughly, the clause).
Since "himself" is not c-commanded by "John" in sentence [3], Principle A is violated.

*'''Principle B:'''  a pronoun must be free (i.e., not bound) within its governing category (roughly, the clause).
In sentence [1], "him" is bound by "John", violating Principle B.

*'''Principle C:''' an [[R-expression]] must be free (i.e., not bound). R-expressions (e.g. "the dog" or "John") are referential expressions: unlike pronouns and anaphora, they independently refer, i.e., pick out entities in the world.
In sentence [4], the first instance of "John" binds the second, violating Principle C.

Note that Principles A and B refer to "governing categories"—domains which limit the scope of binding. The definition of a governing category laid out in ''Lectures on Government and Binding''<ref name = LGB/> is complex, but in most cases the governing category is essentially the minimal clause or complex NP.