Projection principle
The projection principle is a stipulation proposed by Noam Chomsky as part of the phrase structure component of generative-transformational grammar. The projection principle is used in the derivation of phrases under the auspices of the principles and parameters theory.
Details
Under the projection principle, the properties of lexical items must be preserved while generating the phrase structure of a sentence. The principle, as formulated by Chomsky in Knowledge of Language: Its Nature, Origin and Use (1986), states that "lexical structure must be represented categorically at every syntactic level" (Chomsky 1986: 84). Chomsky further defined the projection principle as "representations at each level of syntax(MF, D, S) are projected from the lexicon in that they observe the subcategorisation properties of lexical items."
This refers to the fact that every individual piece of a syntactic structure is part of a particular category[1] (i.e. “John” is a member of the category Noun and “run” is a member of the category Verb). The Projection Principle requires that reference to these categories surfaces at every level of a syntactic phrase structure[2]. This requires a knowledge of arguments and internal structures. “John” may be a noun, but nouns are always dominated by a determiner phrase (DP). The verb “run” does not select for the noun “John”, but rather it selects for the DP “John”. The Projection Principle simply states that when notating the syntactic structure of a sentence such as “John runs fast.”, we must specify at every level what lexical category each piece of the sentence belongs to[2] Two common ways of notating the syntactic structure of a sentence under X-Bar Theory include bracketing and tree drawing.
The bracketing for the sentence "john runs fast", generated in line with X-bar Theory, is as follows:
[CP[C'[C e][TP[DP[D'[D e][NP[N'[N John]]]]][T'[T_EPP [V run] [T -s]][VP[VP[<DP>[D'[D <e>][NP[N'[N <John>]]]]][V'[<V> <run>]]][AP[A'[A fast]]]]]]]]
Each uppercase letter in the above bracketing represents a category being specified. We see NP (noun phrase) followed by N' (N bar), followed by N (noun) because the projection principle requires that the category of "John", Noun, be represented throughout the structure.
The verb run has an obligatory argument, its subject (a DP theme), which must appear in the sentence. The following subcategorization frame for the verb run specifies its properties. The subcategorization frame of run is as follows:
- run Verb, [DP theme __ ]
An adverb such as fast has its own subcategorization frame:
fast Adverb, [VP_]
It is out of this frame that a sentence like the following can be generated:
- John runs fast.
If either of these subcategorization frames are violated, so is the projection principle, and the utterance would be ill-formed:
- *Runs fast.
- *John fast.
Before the projection principle was proposed, phrase structures were generated in separation from the properties of lexical entries. These were hypothesized to enter the slots in pre-generated structures waiting to be filled by the lexical material. According to more recent theories, phrase structures are not generated by phrase structure rules, but are "projected" from the lexical entries. The projection principle therefore obviates the need for phrase structure rules in the generative component.
In 1982, Noam Chomsky proposed the extended projection principle as an addendum to the projection principle.[2]
References
- ^ Tesnière, Lucien (2015). Elements of Structural Syntax. Amsterdam/Philedelphia: John Benjamins Publishing Company. p. 41. ISBN 978 90 272 6999 7.
- ^ a b c Chomsky, Noam (1982). Some concepts and consequences of the theory of government and binding. MIT Press. p. 10.
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