Projection principle
Encyclopedia
The Projection Principle is a stipulation proposed by Noam Chomsky
as part of the Phrase Structure Component of Generative-Transformational Grammar
. 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, states that "lexical structure must be represented categorically at every syntactic level". For example, the verb strangle, apart from the subject, has an obligatory argument, its object, which must appear in the sentence. The following subcategorization frame
for the verb strangle specifies its properties; the underlined gap for the location of the verb is followed by the noun phrase (NP):
It is out of this frame that a sentence like the following can be generated:
A sentence without the object, in violation of the verb's subcategorization frame and the Projection Principle, would be ill-formed:
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.
Noam Chomsky
Avram Noam Chomsky is an American linguist, philosopher, cognitive scientist, and activist. He is an Institute Professor and Professor in the Department of Linguistics & Philosophy at MIT, where he has worked for over 50 years. Chomsky has been described as the "father of modern linguistics" and...
as part of the Phrase Structure Component of Generative-Transformational Grammar
Generative grammar
In theoretical linguistics, generative grammar refers to a particular approach to the study of syntax. A generative grammar of a language attempts to give a set of rules that will correctly predict which combinations of words will form grammatical sentences...
. 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, states that "lexical structure must be represented categorically at every syntactic level". For example, the verb strangle, apart from the subject, has an obligatory argument, its object, which must appear in the sentence. The following subcategorization frame
Subcategorization frame
In syntax, a subject within linguistics, the subcategorization frame of a word is defined to be the number and types of syntactic arguments that it co-occurs with...
for the verb strangle specifies its properties; the underlined gap for the location of the verb is followed by the noun phrase (NP):
- strangle Verb, [__ NP]
It is out of this frame that a sentence like the following can be generated:
- Fabio strangled Prince Jamal.
A sentence without the object, in violation of the verb's subcategorization frame and the Projection Principle, would be ill-formed:
- *Fabio strangled.
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.