Logical Form (linguistics)

In some theories of syntax and grammar, in particular in the Chomskyan schools of government and binding theory and the minimalist program, the Logical Form (abbreviated LF and conventionally spelled with capital initial letters) of a linguistic expression is a mental representation of it, derived solely from surface structure. In the words of Noam Chomsky, LF captures "those aspects of semantic representation that are strictly determined by grammar, abstracted from other cognitive systems". It functions as the interface between grammar and conceptual-intentional properties of language, analogous to how the phonetic form (abbreviated PF) is the interface between grammar and the audio-perceptual properties of utterances.

Logical Form is the level of representation that affects the semantic interpretation of a sentence. LF is sometimes referred to as a covert level of representation, because the output of this level is not actually pronounced by the speaker.

Worth noting is that many theories of syntax do not acknowledge Logical Form (e.g. Lexical Functional Grammar, Head-Driven Phrase Structure Grammar, Dependency Grammars, Tree-Adjoining Grammar, etc.), at least not in the way it is understood in Government and Binding Theory and the Minimalist Program. The postulation of such a level of representation remains a subject of debate.

The notion of Logical Form was originally invented for the purpose of determining quantifier scope. As the theory around the Minimalist program developed, all output conditions, such as theta-criterion, the case filter, Subjacency and binding theory, are examined at the level of LF. The study of LF is more broad than the study of syntax.

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