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Logical Form Tree

In the field of linguistics, specifically in syntax, logical form (abbreviated 'LF'), refers to a certain level of mental representation of a linguistic expression, derived from surface structure. LF is the semantic equivalent of Phonetic Form (PF), a representation of the sound of a sentence derived from its surface structure.

Logical form is the level of representation which fully determines the semantics 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.^[1] LF is posited in syntax in order to give a structural account of certain kinds of semantic ambiguities. For example, the sentence,

Everyone loves someone

is semantically ambiguous. Specifically, it contains a scope ambiguity. This ambiguity cannot be resolved at surface structure, since someone, being within the verb phrase, must be lower in the structure than everyone (though see [1]). Generative semanticists argued that the ambiguity should be resolved at Deep Structure (or at least, some level of representation preceding Surface Structure in the derivation), but Noam Chomsky and his student Robert May argued in favor of an LF account. At LF, the sentence above has two possible structural representations, one for each possible scope-reading, in order to account for the ambiguity by structural differentiation. In this way, it is similar in purpose, but not the same as Logical form in logic.

1. ^ Ouhalla, J: "Introducing Transformational Grammar." 2nd Ed., page 68. Arnold Publishers, 1999

• http://kleene.ss.uci.edu/~rmay/LogicalForm.html

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