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Language, Logic, and Meaning. USEM 40a Spring 2006 James Pustejovsky. Thanks to Dan Wedgewood of U. Edinburgh for use of some slides. The study of meaning. What does ‘meaning’ mean? To what extent is it a linguistic matter?

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Language logic and meaning l.jpg
Language, Logic, and Meaning

USEM 40a

Spring 2006

James Pustejovsky

Thanks to Dan Wedgewood of U. Edinburgh for use of some slides

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The study of meaning

  • What does ‘meaning’ mean?

  • To what extent is it a linguistic matter?

  • What kind of theory of meaning is best suited to the linguistic facts?

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Two Views of Meaning

  • Mentalistic Theory

    • Focuses on how expressions map to concepts

  • Referential Theory

    • Focuses on how expressions map to world

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Place of Semantics in Linguistics

  • Expressions are built up with structure

    • Syntax

  • Expressions refer to things

    • Semantics

  • Expressions are uttered in context

    • Pragmatics

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Properties of the Utterance

  • Intention behind u

  • Context of use of u

  • The speaker and hearer of u

  • Structure of u

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Reference and Meaning

  • Referring Expressions: a specific referent is picked out

    • I want that cookie.

  • Non-Referring Expressions: a generic interpretation

    • I want a dessert. I don’t know what, just anything

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Extensions and Referents

  • Referent: the thing picked out by uttering the expression u in a specific context

  • Extension: the set of things which are possibly referred to by the expression u.

  • Denotation: the relationship between an expression u and its extension.

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Names and Noun Phrases

  • Description Theory

    • Names are shorthand descriptions for knowledge about the referent

  • Causal Theory

    • Names are socially inherited from a chain of uses going back to a grounding.

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Kinds of Denotation

  • Proper Names denoteindividuals

  • Common nouns denotesets of individuals

  • Verbs denoteactions

  • Adjectives denotepropertiesofindividuals

  • Adverbs denotepropertiesofactions

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Structure of Utterance

  • Individual Word Meanings

    • Lexical Semantics

  • Word meanings in combination

    • Compositional Semantics

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Necessary and Sufficient Conditions

  • X is an A if and only if P and Q and …

  • What properties are necessary?

  • What properties are sufficient?

  • E.g., bird, game, book, ground rule double

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Meaning and the lexicon

  • Componential analysis

    bachelor = [+male, -married, +adult]

  • Sense relations

    synonymy, antonymy, hyponymy…

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Meaning and Grammar

Compositional meaning:

The cat chased the dog.

The dog chased the cat.

The cat ate the hat.

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Semantics and Grammar

  • Linguistic semantics: the output of combining words through the syntax

  • …though syntax can produce meaningless grammatical structures too:

    Colorless green ideas sleep furiously.

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The Principle of Compositionality

The meaning of an expression is a function of the meaning of its parts and the way they are put together.

-Gottlob Frege

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The Principle of Compositionality

The syntax-semantics relationship isn’t always straightforward:

  • a blue pen

  • a beautiful dancer

  • a criminal lawyer

    Where do the differences originate? The lexicon? Syntax? Semantics? Pragmatics (i.e., world knowledge)?

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Constraining linguistic semantics

  • We want to account for the linguistic contribution to meaning

  • Competence-basedapproach:

    we aim to characterize the knowledge that language users have (just asin syntax).

  • …specifically, knowledge of how language contributes to meaning

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Approaching linguistic semantics

Not all meaning that arises in ‘performance’ is part of semantics (as a branch of linguistic competence):

{11:45 am}

John: Want to join us for lunch?

Mary: a. I have a class at noon.

b. I have a class at 3:00 pm.

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Semantics v. pragmatics (I)

One view:

  • Meaning from the language = semantics

  • Meaning from the context= pragmatics

    (identity of / relationship between speaker and hearer, situation, beliefs, intentions …)

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But what is meaning?

  • So we’re restricting ourselves to linguistically-determined meaning

  • But what is it to know that some piece of linguistic structure affects meaning?

  • We need a theory of what it means to say that a sentence ‘means something’

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Knowledge of Linguistic Meaning

Some things we know about meaning:

  • Paraphrase: P is true, if and only ifQ is true

    P: Bill was killed by Phil.

    Q: Phil caused Bill to die.

  • Contradiction: if P is true, then Q is false

    P:Phil is a murderer.

    Q: Phil has never killed anyone.

  • Entailment: if P is true, then Q is true

    P:Phil killed Bill.

    Q1:Phil killed someone.

    Q2:Someone did something in the past.

    (cf. synonymy, antonymy, hyponymy)

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Semantics and Truth

Note that all these meaning relations depend on the truth (or falsity) of each sentence

  • So can we define meaning in terms of truth?

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Semantics vs. Pragmatics

A different criterion: truth conditions

To know what a sentence means is to know the circumstances under which it is true(=its truth conditions)

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Semantics vs. Pragmatics

A different criterion: truth conditions

  • Semantics (of a sentence)= what must hold true in the world for the sentence to be judged true

  • Pragmatics = all speaker or context related meaning

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Language and truth-conditions

We’ve considered two definitions of semantics: (i) what linguistic forms encode and (ii) truth conditions

  • Both are ways to get at the invariant meaning of a sentence.

    (Sentence meaning, as opposed to utterance meaning)

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Language and Truth-Conditions

We will continue to treat a sentence as ‘having truth conditions’

  • Enables discussion of semantic knowledge

    • paraphrase, contradiction, entailment

  • Connects linguistic meaning to the world

  • But truth depends also on context

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  • “A sentence has truth conditions” – equivalently, it conveys propositional content

  • A proposition has a truth value(T or F)

    It is a statement that certain truth conditions hold

    Often thought of as a state of affairs in the world

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A proposition is usually expressed as the meaning of a sentence:

  • The Red Sox won the World Series last year.

    • That sentence contains nine words. (Sentence)

    • That sentence is true (Proposition)

      Another possibility would be to express propositions in a formal metalanguage

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Entailment is a relation between sentences or sets of sentences, the premises and conclusions.

  • A entails B if B follows from any utterance of A.

  • A entails B if any way of making A true makes B true too.

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An implicature is to read between the lines. Conversational implicatures arise from the interplay of semantic interpretation and general principles of social interaction or conversation.

  • Fritz had a flat tire this morning.

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A presupposes B if B follows from A, and B follows from the negation of A .

  • Have you stopped smoking?

  • John didn’t answer the phone.

  • Mary regrets that she insulted her mother-in-law.

  • Fritz managed to make it to class on time.