page_title: C-command
section_title: Binding Theory
hierarchical_section_title: C-command / Applications / Binding Theory
caption_attribution_description: English: Tree illustrating Binding and c-command- sentence 2
context_page_description: c-command is a relationship between the nodes of grammatical syntax trees. A working definition of c-command is that node X c-commands node Y if a mother of X dominates Y. C-command is closely associated with the generative phrase structure grammars of the Chomskyan tradition, and is not applicable to the tree structures of other theories of syntax, such as dependency grammars. C-command relations have served as the basis for many explorations and explanations of phenomena within the field of syntax. It has been taken to be the basic configurational relation underlying binding, and has played a central role in the analysis of diverse syntactic mechanisms, such as parasitic gaps and the scope of quantifiers.
  Informally, if a node has any sibling node, then it c-commands its siblings and all of their descendants; however, if a node doesn't have any siblings, then it c-commands everything that its parent c-commands.
context_section_description: One application of the c-command relation is found in the study of binding, which investigates the possible syntactic relationships between personal pronouns and their antecedents.
  Binding Theory consists of three principles, and the role of c-command differs amongst them: 
  Principle A: An anaphor (e.g. reflexives such myself, yourself, herself, himself, ourselves, yourselves, ourselves, themselves and reciprocals such as each other, one another) must be bound in its domain (that is, it must be c-commanded and co-indexed with a DP within its domain)
  Principle B: A pronominal (e.g. personal pronouns such as I, me, my, you, your he, him, his, she, her, we, us, our, they, them, their) must be free in its domain (that is, it must not be c-commanded and co-indexed with a DP within its domain)
  Principle C: An R-expression (e.g., John, Lucy, the dog, etc..) must be free (that its, must not be c-commanded and co-referenced)
  In order to establish binding, the bound element must be c-commanded and be co-referenced with an antecedent element.  Without a c-commanding relationship, binding cannot be established.  
  
  These relationships between pronouns and antecedents appear to be subject to certain restrictions. For example, it is hypothesized that a pronoun cannot appear in a position where it c-commands its antecedent (Binding Theory Principle B). Consider the sentences: 
  Sentence 1: [He]ⱼ said that John]ₖ was coming.
  Sentence 2: [His]ₖ mother said that [John]ₖ was coming.
  In the first sentence, "he" cannot refer to John. This was explained, at least in the original binding theory, by the fact that he c-commands John in the first sentence, whereas his does not c-command John in the second.	 
  In the second sentence, his and John may co-refer ("his mother" may mean John's mother).  Crucially, however, the pronominal [his] does not c-command the R-expression [John], as the sister of the D [his] is the NP (noun phrase) which dominates the terminal node [mother] and not the terminal node [John], making this a grammatical sentence because the pronoun is free in its domain.
  C-command in Principle A of binding theory:	
  Sentence 3: [Mary]ₖ talks about [herself]ₖ.
  The anaphor “herself” is subject to Principle A of binding theory and must be bound in its domain. This means that “herself” must be co-referenced (as indicated by subscript k) with an antecedent [Mary] and be c-commanded by the antecedent, meaning that the sister of the DP [Mary] must dominate the DP [herself].  
  Principle C of Binding Theory can be seen in the tree at the left.  The R-expression Mary is not c-commanded by any antecedent DP in the structure, making this a grammatical sentence.
caption: Tree illustrating c-command in sentence 2, Principle C of Binding Theory
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