Albert Gatt - PowerPoint Presentation

Slide1

Albert Gatt

LIN3021 Formal Semantics

Lecture 10Slide2

In this lecture

We shift our focus to events, and ask:

How should we think of events in natural language?

How

do we treat semantic issues related to events, specifically:

The nature of events and event modification

Time and tense

Aspect and event structure

Modality and possibilitySlide3

What is an event?

So far, we’ve thought of verbs (transitive and intransitive) as predicates and relations:

[[

sleep

]]

= [[eat]] = This puts them on a par with nouns:[[man]] = Slide4

Predicates of what?

But notice:

The argument of the semantic representation of the noun is an

individual

(an “entity”)This is evident in a typical predicative construction:Sam is a man And if we add premodifiers, we assume they’re <<e,t>,<

e,t>>, i.e. Take a noun predicate and return a complex noun predicate:Sam is a tall manSlide5

Predicates of what?

But what about events?

With

Sam eats

, it seems to be similar to the nominal case:

eat(s)But what about Sam eats quickly? What is the argument of quickly? Do we want eat(s) & quick(s)?Many semanticists argue that verbs actually denote an

implicit event argument.

I ate a meat pie roughly means:There is an event, and this event is an eating event, and the event involves me as agent, and a meat pie as patient

In other words, rather than a relation between two things (an eater and an

eatee

), we

might

think of this as a relation between three things (an event, and the eater and

eatee involved in it)Slide6

A preliminary example

Strange goings on! Jones did it slowly, deliberately, in the bathroom, with a knife, at midnight. What he did was butter a piece of toast.

Davidson, 1980 [1967], p. 105

Some questions/observations:

What does

it refer to in that sentence? (The buttering event?)We have the intuition that slowly, deliberately, in the bathroom etc modify the same buttering event involving Jones and the toast.There is a difference between:Adverbs like

slowly, which actually modify the event itselfPhrases like in the bathroom,

with a knife etc, which seem to add arguments to the event in addition to Jones and the toast.Slide7

The phenomena we want to look at

Strange goings on! Jones did it slowly, deliberately, in the bathroom, with a knife, at midnight. What he did was butter a piece of toast.

Davidson, 1980 [1967], p. 105

We’re going to consider three classes of phenomena:

Thematic roles

Event modifiers and their relationship to nominal modifiersEvent reference and nominalisationSlide8

Part 1

Evidence from thematic rolesSlide9

Thematic roles

We’ve encountered thematic roles

before...

Roughly, these are semantic categories that specify the roles of arguments of events:

Agent, patient, location, instrument etc

Their main theoretical function is to allow us to:Categorise the arguments of verbs (and of some other predicates)Make generalisations about how they combine with predicatesSlide10

An example

John buttered the toast.

The toast was buttered by John.

John

= the agent

The toast = the patientThe roles stay the same whether it’s active or passive.Notice that we don’t have a verb (say, sbuttered) which would be synonymous with buttered-in-the-passive and would reverse the roles:

The toast sbutttered John (=the toast was buttered by John).Why?Slide11

Generalisations

The apparent non-existence of verbs like

sbuttered

, with

reversed

agent/patient roles, suggests that language:is biased towards having specific properties for agents and patients (John is a more likely agent of a buttering event)maintains these roles even if the event is conceptualised in terms of the reverse relation (as with the passive)Typically:

Agent maps to subjectIf there is no agent, but there is a patient, then patient maps to subjectIf there is both an agent and a patient, then (1) applies, and patient maps to object.Slide12

An aside on Maltese and related languages

Superficially, we do seem to find languages that allow the equivalent of “

sbuttered

”, i.e.:

Take a verb with Agent and Patient

Add something to it to morphologically to reverse the roles.Pawlu qatel raġelRaġel

inqatel minn

PawluBut note:The roles are not

being reversed (

Pawlu

is still agent)

The verb

nqatel is arguably marked with respect to the base form qatel.

This suggests that the “passive” is not the basic form.Slide13

Agent and patient of what?

John buttered the toast.

The toast was buttered by John.

Notice that we have the

same event

viewed in different ways: It’s the same action in both cases (a buttering)It involves an agent and a patient in both cases.We might take this as prima facie

evidence for the argument that:There is a single event underlying these two sentences (call it e)The agent and patient roles are relations between the event and an individual. E.g.

AGENT(e) = JohnPATIENT(e) = the toastSlide14

Things to note

If we adopt this view, then we no longer think of

butter

as a 2-place predicate involving 2 arguments. We would think of

butter

as also involving an implicit event argument.Semantically, it might look like this:In other words, we think of event sentences as:Implicitly involving an event argumentRelating the explicit arguments directly to the event itself

So we no longer analyse this as a 2-place predicate along the lines of butter(j,t).Slide15

Some further evidence

John buttered the toast.

John buttered the toast

with a knife

.

Here, we seem to have introduced additional arguments!If we assume that [[butter]] is a two-place predicate in the first example, what happens in the second case?Do we want to have to say that butter is ambiguous?2-place

butter: agent, patient3-place butter: agent, patient, instrument...Slide16

Some further evidence

John buttered the toast.

John buttered the toast

with a knife

.

Our event-based analysis would allow us to avoid this kind of argument.In the second sentence, all we’ve done is introduce a third role (instrument), but it’s still the same butter predicate (only we’ve added an optional argument):Slide17

A complication

(1)

Sam hit the table with a hammer

(2)

Sam hit the hammer against the table.

Do we have the same event here? Intuitively, perhaps, we do.Given an actual event in a world/model, could we describe it in either of these two ways?But the thematic roles seem different in the two cases: Sam does something to the table in (1), but to the hammer in (2).

By our earlier generalisations, table is the patient in (1), but hammer is patient in (2).

If we we want to keep the traditional thematic role analysis, we’d be forced to conclude that hit takes different arguments in (1) and (2).But

then, we can’t really say it’s the same event! The two have different participants

.

Two different entries for

hit

?Slide18

Dowty’s (1990)

theory

Sam hit the table with a hammer

Sam hit the hammer against the table.

Perhaps we should instead think of these as “prototypes”:

Proto-agent entailments: volitional, sentient, causer, moves, exists independentlyProto-patient entailments: undergoes change, changes portion by portion, causally affected, stationary, doesn’t exist independently.

Under this view:Sam is more agent-likeBoth hammer and

table are roughly equally patient-like; hence we have a choice about which becomes the object.Hit is the same in the two cases; it’s just that we have an option about which argument to map to the patient role.Slide19

Interim summary

We’ve adduced some evidence for events involving an implicit event argument:

The same events can be conceptualised in different ways (e.g. active/passive) but retain the same thematic roles

The thematic roles relate the event to its arguments

Additional roles can be introduced (often through PPs) and these are just conjoined to the whole interpretation.

We’ve also seen some reasons for thinking of roles as being “prototypical”. This helps in maintaining the event analysis, and dealing with variable mappings to the syntax.Slide20

Interim summary cont/d

Things to note about the analysis:

There is an implicit event argument

Thematic roles are relations between the event and its arguments

The event argument is existentially bound (

there is an event...)Slide21

Part 2

Event modifiersSlide22

Our original example

Jones buttered the toast slowly, in the bathroom, with a knife, at midnight.

Here we have:

Prepositional phrases introducing “extra” or “optional” arguments (instrument, location)

Manner adverb (

slowly)Time adverbial (at midnight)These are all “event” modifiers – they add some more information to the basic event of John buttering the toast.Slide23

Questions

How should event modifiers be analysed?

Do verb modifiers have anything in common with adjective modifiers?

Can we have a single, unified theory?Slide24

Some observations

Event modifiers exhibit two interesting phenomena, which, following

Landman

(2000), we’ll

cal

l permute and dropPermute:John buttered the toast slowly, in the bathroom, with a knife.

John buttered the toast in the bathroom, slowly, with a knife.We can permute the order of modifiers, and this seems to make no difference to the interpretation. (One entails the other)

Drop:John buttered the toast slowly, in the bathroom, with a knife.

John buttered the toast in the bathroom with a knife.

If (1) is true, then it entails (2).

In a sentence S with

n

modifiers, if we form a new sentence S’ from S by dropping one or more of these modifiers, then S

 S’.Slide25

The parallel with adjectives

Adjectival

premodifiers

of nouns seem to exhibit the same properties.

Permute:

John is a dark, thirty-something, Maltese manTherefore, John is a thirty-something, dark, Maltese man.Drop:John is a dark, thirty-something, Maltese manTherefore,

John is a thirty-something, Maltese manSlide26

More parallels with adjectives

Adjectives:

If we set things up so that we’re talking about the same individual, then inferences of the following sort seem to be ok:

John is a dark man.

John is a basketball player.

Therefore, John is a dark basketball player.But we’ve noted that some adjectives are exceptions to this (so-called “intensional” adjectives):John is a former president.

John is a basketball player.*Therefore, John is a former basketball player.Slide27

More parallels with adjectives

Adverbs:

If we set things up so that we’re talking about the same event, then inferences of the following sort seem to be ok:

Caesar stabbed Brutus with a knife.

Caesar killed Brutus.

Therefore, if the event here is the same one: Caesar killed Brutus with a knife.But some adverbs resist this (those related to belief, state of mind etc):Caesar stabbed Brutus intentionally.

Caesar killed Brutus.*Therefore, if the event here is the same one: Caesar killed Brutus intentionally.

NB: it is crucial that we assume that the event is the same one! (Just as it’s crucial in the adjective examples that we’re talking about the same individual)Slide28

Can we exploit the parallels?

Except for a particular class of adjectives, we find remarkable flexibility in

premodification

of nouns, given permute and drop.

Recall that, in our earlier analysis, we distinguished between:

Predicative adjectives (John is tall) which are just properties: tall(j). Type: <e,t>Attributive adjectives (

John is a tall man) which take a noun predicate (<e,t>) and return a complex noun predicate (also of type <

e,t>). So the attributives have type <<e,t>,<e,t>>Slide29

Attributives

Attributive adjectives (

John is a

tall

man

) are of type <<e,t>,<e,t>>, so they’re not simple predicates.What is their relationship to their predicative counterparts (John is tall

)? These have simpler types (<e,t>) and so seem more basic.

Let A be an attributive adjective, and Ap be its predicative counterpart. We might analyse the attributive as:

This says: the attributive adjective takes a noun meaning and applies this to

x

. It also applies the basic adjectival meaning corresponding to A, to the same individual

x

.

Crucially, the adjectival meaning is conjoined to the nominal meaningSlide30

Attributives

Now, if attributives take a noun predicate and return a new complex predicate, we know that this can be done recursively:

If we apply the above function to

man

we get

dark man (which is itself of type <e,t>) To get fat dark man, we combine the above with the entry for fat:Slide31

Permute and drop with adjectives

The crucial observation is that the semantic analysis of complex NPs with multiple attributives views these as

conjunctions

.

The predicates are applied to the

same argument (the same individual is a man, dark and fat)Logically, if we have P & Q, then:This implies P (i.e. From P & Q we can drop Q to get P)

This is logically equivalent to Q & P (i.e. We can permute P&Q)This seems to be exactly what we want...Slide32

Adverbs

Brutus ate quickly with a fork

We want to capture the same permute/drop phenomena with verb modifiers.

So, we might say that the above involves conjunction.

Just like

dark fat N is something like [dark(x) & fat(x) and N(x)]Let’s think of this example as something like:[quick(x) & with-a-fork(x)]Problem:With John is a dark fat man, we know what x

is (namely, John)But what is the x with quick and

with a fork?Slide33

Take 1: subject modification

Brutus ate quickly with a fork

Here’s a suggestion:

Maybe

quickly

modifies the subject (Brutus), which is also the argument of the verb.eat(b) & quick(b) & with-a-fork(b)(Simplifying the analysis of with a fork for the moment)

Problem:It doesn’t seem natural to say that quickly is a property of Brutus himself (it’s a property of what he does)

Consider:Kim tapped Susumo

lightly

(after Landman, 2000)

Kim

is a Sumo wrestler. He’s anything but light. We don’t want to say that

lightly(x) involves predicating light of Kim.Slide34

Take 2: the event argument

Brutus ate the toast quickly with a fork

We can resolve this problem if we take up our earlier suggestion:

Events involve an implicit event argument

The modifiers modify this argument directly.Slide35

Compositional interpretation

Takes two arguments, but also introduces an implicit event

e

Just like an attributive adjective, requires a verb predicate

V

to return a complex verb.Slide36

Compositional interpretation

Brutus ate the toast quickly

To get the full interpretation, we first apply this to

the toast

:

...and then to Brutus:Slide37

Adding modifiers

Brutus ate the toast quickly with a knife

To get the permute and drop phenomena, we want to have simple logical conjunction of

quickly

and

with a knife:Observe that our logical form says:Quickly is a property of the event

(as are the thematic roles)The thematic roles are relations between the event and individuals.

We get the right entailments: Brutus ate the toast quickly (drop with a knife

)

 Brutus ate the toast with a knife (drop

quickly

)

 Brutus ate the toast (drop both)

 Brutus ate the toast with a knife quickly (permute)Slide38

Part 3

Event referenceSlide39

Event reference

We are often able to refer back to an event, as though it were a thing. Compare:

John

met

Sally

. She was very pretty.She clearly refers back to the individual Sally.

This suggests that we have some “mental representation” of the individual to refer back to.Usually, we think of these NPs as introducing a variable. So she can then hook on to the variable introduced by

Sally.John met Sally. It was really traumatic.

It

refers back to the event.

This suggests that we have some “mental representation” of the event to refer back to. Where does it come from?

Just as

Sally

introduces an individual variable in the discourse, perhaps meet introduces an event variable.Slide40

Event reference

Language allows us to “nominalise” events, i.e. To take verbs and turn them into nouns (or

nouny

things, like gerunds).

In

fact, we are able to quantify over events the way we quantify over individuals:Every farmer eats meat. Every burning consumes oxygen.We could think of these events as predicates. The noun farmer is semantically a predicate of individuals (the property of things which are farmers).

The noun theft is semantically a predicate of ... What? The things which are thefts are events.

This would also capture the relationship between verbs and their nominalisations quite straightforwardly.Slide41

Summary

We’ve proposed (following Davidson) that events can be viewed as introducing an implicit event argument.

Under this theory, we are able to:

Deal quite flexibly with events having different numbers of participants in different contexts (

eat, eat with a knife

etc)Deal with event modification in much the same way that we deal with adjectival modificationAccount semantically for permute and drop phenomena