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The Nature of LanguageLecture 8 (Week 10): Semantics

2013-2014

Semester 1

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What do we do today?

Todays topic - Semantics

Semantics is the study of meaning.

We talk about the meaning of words andsentences.

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Two types of meaning

Suppose a lady gives me a call and asks,

I cant go out on a date.

I am married.

I have a wife.

Would youlike to go out

on a datewith me?

Literal Meaning

Speaker Meaning(Implicature)

Todays topic

Next weeks topic

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Word meaning: Concepts and Objects What is the meaning of a word?

Chair

Conceptof chair What is the meaning of a word?

(i) The name of a concept in ourmind (intension/sense).

(ii) It refers to the worldly objectscharacterized by the concept.(extension/reference)

Referential/extensionalmeaning of the word

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Concepts

Do we really have concepts in our minds thatwords represent?

If yes,

How do we know/show that we have them?

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Concepts A simple game to show that we have concepts:

Instruction - Give me the name of the color in which eachof the following words is written.

Black Yellow

BlueRedPurple

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Concepts A simple game to show that we have concepts:

Instruction - Give me the name of the color in which eachof the following words is written.

Black Yellow

BlueRedPurple

Its hard to turnoff the conceptthat a wordbrings up in ourmind when wesee the word.

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Concepts: semantic relations With concepts in our minds, we can identify

various semantic relations that hold betweenwords.

Bachelor Male

ChairIf x is a bachelor, x is a male.The meaning/semantic relation: hyponymyBachelor is a hyponym of Male.

Closely related

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Concepts: semantic relations

Given the two words, Male and Bachelor

Male Bachelor

Bachelor is a hyponym of Male .The superordinate term, Male, is a hypernymof Bachelor

Male

Bachelor

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Concepts: semantic relationsTask : Answer the following questions.

(1) What are the hyponyms of animal ?

(2) List the hyponyms of color .

(3) List the hyponyms of emotion .

Dog, horse, bird, etc.

Red, blue, green, etc.

Anger, fear, love, etc.

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Task : Now, consider the following words.

stubborn obstinate

Is stubborn a hyponym of obstinate ?

Is obstinate a hyponym of stubborn ?

If two words are hyponyms of each other, they are said tobe synonymous .

Yes

Yes

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Some examples of synonymssofa couchbig largepurchase buyautomobile carremember recall

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Concepts: semantic relations Antonyms are words that are opposites with

respect to some component of their meaning.

DEFINITION BINARY ANTONYMS are words which come in pairs

and between them exhaust all the relevantpossibilities. If the one word is applicable, thenthe other cannot be, and vice versa.

EXAMPLE true and false are binary antonyms.

If X is not true, X is false.

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T ASK : Are the following pairs of words binaryantonyms?

(1) chalk - cheese (2) same - different (3) copper - tin

(4) dead - alive (5) married - unmarried (6) love - hate

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Concepts: semantic relations CONVERSES (D EFINITION ) If a word describes a relationship between

two things (or people) and some other worddescribes the same relationship when the

two things (people) are mentioned in theopposite order, then the two words areCONVERSES of each other.

EXAMPLE Parent and child are converses, because X

is the parent of Y (one order) describes thesame situation (relationship) as Y is thechild of X (opposite order).

A B X A Y Y B X=

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Task : Are the following pairs of expressions converses?

(1)Below-above (2) Grandparent-grandchild

(3)Love-hate

(4)Conceal-reveal (5)greater than-less than (6) own-belong to

X is below Y Y is above X

X is a grandparent of Y Y is a grandchild of X

X loves Y Y hates X

X conceals Y Y reveals XX is greater

than YY is less than

X

X owns Y Y belongs to X

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Task : Consider the following words.

hot and cold

Would you consider them antonyms?Would you consider them binary antonyms like male and female ?

No.Negation of male means female , butNegation of hot does not necessarily mean cold .

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DEFINITIONTwo words are GRADABLE ANTONYMSif they are atopposite ends of a continuous scale of values (ascale which typically varies according to thecontext of use).

hot Cold =

A good test for gradability is to see whether theyare compatible with very or very much.

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Concepts: semantic relationsT ASK : Classify the following pairs as binary antonyms,

converses, or gradable antonyms.

(1) easy-difficult (2) good-bad (3) better than worse than (4) deciduous evergreen (5) pass-fail

g

g

c

B

B

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Concept: Fundamental questions Our mind is full of concepts.

Conceptof chair

Conceptof

horse Conceptof animal

Conceptof eating

Conceptoffurniture

How do we define a concept?

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ConceptHow do we define a concept?

Definitional theories of word meaning (truth-conditionaltheories) :The concept of a word X is a necessary andsufficient set of conditions that an entity isrequired to satisfy in order to count as an instance ofX.

CHAIR:it is (a) a piece of furniture (b) for one person(c) to sit on, (d) having a back and (e) four legs.

BACHELOR: A person who is an (a) unmarried (b) adult (c) male.

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Concept

How do we define a concept? With the pieces of knowledge that constitute concepts,

we can tell whether an entity is

chair bachelor

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ConceptHow do we define a concept?

This is basically the method that a dictionaryadopts to define the meaning of words.

We can define all the words in this way.

There are some problems with the definitional

approach to the concepts of words.

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ConceptHow do we define a concept?CHAIR:it is (a) a piece of furniture (b) for one person(c) to sit on, (d) having a back and (e) four legs.

Beanbag chairs

Barber chair

No legs, no back

Not really meant forsitting

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Concept

How do we define a concept? Definitional theories of meaning (defining the

meaning of a word by providing the necessary andsufficient conditions that an entity is required to

satisfy in order to count as an instance of X) arepromising but not without problems.

Other theories of lexical meaning:

- componential theories of meaning- image theories of meaning- prototype theories of meaning

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Concepts:How do we organize them?Semantic Network

HORSE MANE

HAVING

HAY SUGAR EATING

CART

PULLING

JOCKEY HUMAN

RIDING

IS

BACHELOR MAN LAWYER

ANIMAL

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Hyponym

ANIMAL

HUMAN HORSE

MAN LAWYER JOCKEY

BECHELOR..

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Concepts:How do we organize them?Semantic Network

For a peek at a version of semantic network,visit the following website:

http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Semantic_network.html

http://wordnet.princeton.edu/

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Sentence Meaning Just as words are semantically related to each

other, sentences are related to each other in theirmeaning.

Hyponymy is a relation between words.

Something similar to hyponymy holds betweensentences, i.e. entailment .

DEFINITION A proposition X ENTAILS a proposition Y if the

truth of Y follows necessarily from the truth of X.

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Sentence Meaning: Entailment EXAMPLE: John ate all the kippers (X) entails

Someone ate something (Y).

John killed Bill (X) entails Bill died (Y).

It is not possible to think of any circumstances in which

sentence X is true and sentence Y false.

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Sentence Meaning: Entailment T ASK : Look at the following and circle the statements

of entailment as correct (C) or incorrect (I).

(1) John cooked an egg entails John boiled an egg .(2) John boiled an egg entails John cooked an egg .(3) I saw a boy entails I saw a person .(4) John stole a car entails John took a car .(5) His speech disturbed me entails His speech deeply

disturbed me .

I

CC

C

I

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Sentence Meaning: Entailment Task : Do the following sentence entail each other?

(1) John and Mary are twins.

(2) Mary and John are twins.

Two sentences may be said to be P ARAPHRASESof each other, ifand only if they mutually entail each other so that whenever oneis true the other must also be true.

entailsentails

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Sentence Meaning : Entailment

& Paraphrase Task : Look at the following pairs of sentences and see if theyparaphrases of each other.

(1) No one has led a perfect life.

Someone has led a perfect life.(2) Weve just bought a dog.Weve just bought something.

(3) The house was concealed by the trees.The house was hidden by the trees.

(4) I ran to the house.I went to the house.

(5) It is hard to lasso elephants.Elephants are hard to lasso.

No

No

Yes

No

Yes

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Sentence Meaning: A NTONYMS AND

CONTRADICTORIES

DEFINITIONA proposition is a CONTRADICTORY ofanother proposition if it is impossiblefor them both to be true at the sametime and of the same circumstances.

EXAMPLEThis beetle is alive is a contradictory ofThis beetle is dead .

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ANTONYMS ANDCONTRADICTORINESS

T ASK : Say whether the following pairs are contradictoriesor not.

(1) John murdered Bill.Bill was murdered by John.

(2) John murdered Bill.John did not kill Bill.(3) Bill died.

James cant swim.(4) Mary is Anns parent

Mary is Anns child.(5) Room 404 is below this one.

Room 404 is above this one.(6) This doorhandle is brass.

This doorhandle is plastic.

N

Y

N

Y

Y

Y

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The meaning of sentence:Truth conditional semantics

Question : What is the meaning of sentence (1)?

(1) Bart snores.

Do you know the meaning of the sentence?

What exactly is it that you know when you say youknow the meaning of the sentence?

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Truth-conditional Semantics

When you hear (an utterance of)

(1) Bart snores .

This might be what is going on in your mind. (next slide)

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(1) Bart snores .

There is a guycalled Bart

He does this thing

Meaning of (1)Meaning of (1)

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(1) Bart snores.

There is aguy called

Bart

He doesthis thing

Meaning of (1)

This knowledgeThis knowledge

to tell whetherto tell whether

sentence (1) issentence (1) is truetrueoror falsefalse in a givenin a givensituation.situation.

enables us

If what I have inIf what I have inmy mindmy mind(meaning of (1))(meaning of (1))

(1) is true(1) is true

(1) is false(1) is false

holds

If not

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(1) Bart snores .

There is aguy called

Bart

He doesthis thing

Meaning of (1)

to tell whetherto tell whether

sentence (1) issentence (1) istruetrue oror falsefalse in ain agiven situation.given situation.

enables us

the meaningthe meaningof (1)of (1)==

Then, whatwe really

know whenwe say weknow the

meaning of (1)

The truth conditionsThe truth conditionsunder which this sentenceunder which this sentencecan be true (or false)can be true (or false)

This knowledge

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To sum up,

(1) Bart snores .

So, the conceptual meaning of (1) is a set of necessary and

sufficient conditions under which it can be true:(a) There is a guy whose name is Bart.(b) Bart makes a snorting or grunting sound when he sleeps.

Knowing theKnowing the meaningmeaningof a sentenceof a sentence

Knowing itsKnowing its truthtruth--conditionsconditions ..

(what the world would have(what the world would haveto be like for the sentence toto be like for the sentence tobe true).be true).==

Conceptual/inten-sional meaning

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What is the extensional/referential meaning of a sentence?

(1) Bart snores .

The extensionalThe extensionalmeaning of a sentencemeaning of a sentence

== Its truth valueIts truth value(truth or falsity)(truth or falsity)

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Truth-conditional semantics:Computation of the meaning of a sentence

How do we calculate the meaning of a sentence from itsparts?

(1) Bart snores

Two ways to compute a sentence meaning;(i) Combine the intensional meanings of the words in

the sentence.(ii) Combine the extensional meanings of the words in

the sentence.We only talk about this for the sake of simplicity.

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Truth-conditional semantics:Computation of the meaning of a sentence

What are the extensional meanings of the words in (1)?

(1) Bart snores

The set of individuals who snores.

Intension: X isan entity whois referred toas Bart.

Intension: Harsh breathingwith a snorting sound duringsleep

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Truth-conditional semantics: extension

A naive claim about the intensional meaning of Bart?

Bart means all the properties that has.

What do you think of this claim?

PropertiesA naughty boy,

A cartoon character,His skin is yellow,

His last name is SimposnEtc.

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Consider the following name:

Karl Marx

How much do you know about him? If I know very little about him, does it mean that I do

not know the meaning of the name?

I am using the name now in a perfectly sensible manner. If I did not know the meaning of Karl Marx, it would

be impossible for me to use the word.

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The hypothesis about the meaning of proper names:

Bart means all the properties that has.

We may have worldly knowledge about the properties ofa name holder, but that does not count as the meaningof the name.

Properties

A nasty boy,A cartoon character,

His skin is yellow,His last name is Simposn

Etc.

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Back to sentence (1)

Computing the meaning (truth condition) of (1):

(1) Bart snores

Extension: The set of individualswho snore

combine

What is the relation that is established?

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Back to sentence (1)

Computing the meaning (truth condition) of (1):

(1) Bart snores

Extension: The set of individualswho snore

combine

What is the relation that is established?

Hypothesis: the membership relation:

Bart is a member of the set of snoring individuals.

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Summary

When you combine the two words Bart and snore,

Bart snores(1)

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Summary When you say sentence (1), you are claiming that

Bart snores(1)

The meaning of (1)

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Summary Sentence (1) is true.

An Imaginary World

Inhabitants = {Homer, Bart, Lisa, Maggie, Marge}Snorers = {Bart, Homer}

Meaning of snore

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Do you see how the meaning of asentence is calculated in our(extensional) theory of meaning?

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Sentences with adjectives Task : Calculate the meaning of sentence (2).

Treat the copula is as a meaningless element.

(2) Homer is handsome.

The meaning of handsome :

Concept/intension ExtensionThe set of individualswho are handsome.

The set ofhandsomeindividuals.

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Sentences with transitive verbs

Task : Calculate the meaning of sentence (3).

(3) Homer loves Bart.

The meaning of love (transitive verbs):

Concept

What is the extensionalmeaning of love ?

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Task : Calculate the meaning of sentence (3).


The set of pairs wherethe first member in eachpair loves the secondmember.

Extension of love

The members arepairs like ,

, etc.

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In our theory of meaning, when you say (3),


You are interpreted as making the claim:

The set of pairs wherethe first member in eachpair loves the secondmember.

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There are much more to be said abouttruth-conditional semantics

The theory of meaning presented today is rudimentary,which can only deal with very simple sentences like:

(1) Bart snores.

Consider (4).

(4) Every boy likes a girl.Meaning 1: One girl that every boy likes.Meaning 2: For every boy, there is a girl that he likes.

For a full-fledged theory of meaning, sign up for asemantics module.

Our theory of meaning is unable to handle a sentence like (4).

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