Presuppositions (and Focus)

Sabine Iatridou

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What does it mean to understand (the meaning of) a sentence?

• Do you understand this sentence?1. The instructor of this class is wearing glassesIs it true?Yes.Do you understand this sentence?2. The instructor of this class is wearing pink a hat Is it true?No.

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• What about this sentence:3. It is raining in Beijing right nowIs this sentence true or false?You don’t know.Yet, you know what it would take for it to be true. So to understand a sentence, is to know its “truth-conditions”. The truth-conditions of a sentence S1 are the conditions under which S1 is true.

Assertions

Let’s call an ‘assertion’ the act by which one commits oneself to the truth of the sentence uttered. (we will shortly give a better definition)

Often, when we utter a sentence, we make an assertion. But not always.

Can you think of examples where we utter a sentence but do not make an assertion?

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Relations among sentences:Entailment

• A sentence S1 entails a sentence S2 if whenever S1 is true, S2 is true.

(though we will come back to this definition)

4. S1: I drank horseradish vodka and ate serniki

5. S2: I drank horseradish vodka

=>

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Entailment is not about whether a sentence is actually true. The actual fact of the matter is irrelevant. What is relevant is whether the truth of one sentence makes another sentence necessarily true.For example, I suspect that (6) is false:6. All MIT students have tried horseradish vodkaBut even if (6) is false, it still entails (7) and (8):7. Half of MIT students have tried horseradish vodka8. All the students in my syntax class at MIT have tried some type of vodka

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• Entailment does not have to be symmetric. (9) entails (10) but (10) does not entail (9):

9. The cheetah killed the gazelle 10. The gazelle died

Why?

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• But of course, it can be symmetric, as two sentences can entail each other.

• Can you think of two sentences that entail each other?

11. The police arrested the demonstrator12. The demonstrator was arrested by the police

When two sentences entail each other, we say that they are equivalent:S1 and S2 are equivalent if S1 entails S2 and S2 entails S1.

Further inferences

13. Chris believes that gombats futter bravely14. Chris realized that gombats futter bravely

What does (14) convey that (13) does not?

In (14) there is an inference that I / the speaker believes that gombats futter bravely.(this inference is usually described as ‘gombats futter bravely’ being true)

Is this inference cancellable?15a. Chris believes that gombats futter bravely, but I don’t believe it b. Chris believes that gombats futter bravely, but he is wrong c. Chris believes that gombats futter bravely, but I don’t know if they do

16a. #Chris realized that gombats futter bravely, but I don’t believe it b. #Chris realized that gombats futter bravely, but he is wrongc. #Chris realized that gombats futter bravely, but I do not know if they do

17. Chris believes that the earth is flat18. Chris realized that the earth is flat

How about the following predicates? Can you use them without believing that the earth is flat?

hear, discover, be aware that, say, regret

Factive predicates: realize, discover, be aware that, regret

19. What is your opinion about Mimi and Lena?20. I like Lena

Inference:21. I don’t like Mimi that much (or at all)

Is it cancellable?

22.… but I adore Mimi(as a follow-up on 20)

Some inferences are cancellable, some are not.

The inferences that are cancellable are called “conversational implicatures”.

Conversational implicatures are not part of the encoded meaning, unlike entailments (and unlike presuppositions, as we will see shortly).They are inferences that a hearer can draw based on the cooperativity and rationality of the speaker, basically reasoning about the speaker’s intentions.

Implicatures are all around us.

23. Do you know what the time is?

24. A: Do you sell limes? B: I sell lemons

A: What European country will you visit next year? B: One with a Mediterranean coast

Or when we hear numbers:3 children implicates exactly 3 children• When you hear 25a. Max has three childrenthis implicates b. Max has exactly three children

But you can cancel this:26.A: If someone has three children, they are entitled to a tax break B: Max has three children. In fact, he has

four.

Sentence S2 is an implicature of sentence S1, if S2 is inferred upon hearing S1, without being entailed. i.e. S1 can be true without S2 being true i.e. an implicature is cancellable

S1: Max has three childrenS2: Max has exactly three children

Back to the non-cancellable inferences

27. Chris realized that gombats futter bravely

28a. #Chris realized that gombats futter bravely, but I don’t believe it b. #Chris realized that gombats futter bravely, but he is wrong

What is the relationship between (27) and the inference in (29)29. Gombats futter bravely

Is it entailment?

27. Chris realized that gombats futter bravely

entails??

29. Gombats futter bravely

Could the answer to this question be ‘yes’?Could the answer to this question be ‘no’?

Let’s take a case where for sure we are dealing with entailment:

30. I drank horseradish vodka and ate serniki=>

31. I drank horseradish vodka

Chris drank vodka and ate serniki

Did Chris drink vodka and eat serniki?≠>Chris drank vodka

Chris did not drink vodka and eat serniki

≠>Chris drank vodka

Chris realized that gombats futter bravely

Did Chris realize that gombats futter bravely?=>Gombats futter bravely

Chris did not realize that gombats futter bravely

=>Gombats futter bravely

So if the left column shows the bahavior of entailments under questions and negation (the inference disappears), the inferences in the right column should not be called entailments as well, as their behavior is different (the inferences survive questions and negation).

The inferences in the left column do not survive questions or negation. Let’s reserve the term ‘entailments’ for those.

But the inferences in the gombat sentences do. Therefore we should not call these inferences ‘entailments’.

We should call these inferences something else, and explore their properties.

Presuppositions

Presuppositions are inferences that survive questions and negation.

Factive verbs presuppose the truth of their complement.

Factive verbs are ‘presupposition triggers’

But there is more:

32a. Chris realized that gombats futter bravelypresupposes

b. Gombats futter bravely

What happens if a presupposition does not hold (is false)?

33. Chris realized that London is the capital of France

So what is the status of (33)?

Is it a true sentence?Is it a false sentence?

If it is false, negation should make it true:Imagine (34, 35) uttered in a world in which Hedde believes that Paris is the capital of France:

34. Hedde believes that London is the capital of France F

35. Hedde does not believe that London is the capital of FranceT

But negating (36) does not yield a true sentence:

36. Chris realized that London is the capital of France37. Chris did not realize that London is the capital of France

(36, 37) suffer from presupposition failure: it is false (in our world) that London is the capital of France.

What if a sentence suffers from presupposition failure?

Two views: -false (Russell)-undefined (Frege)

What would you say?

Which brings us to one more way to describe presuppositions:

Sentence S1 is a presupposition of sentence S2 if S1 has to be true for S2 to have a Truth-value.

Factive verbs are presupposition triggers.There are many presupposition triggers. Some are verbs, like the factive verbs.

Some determiners (classic example of a presupposition trigger):

38. The present king of France is bald

Presupposes: There is a king of France (= existential presupposition)Presupposes: There is only one king of France

(=uniqueness presupposition)What does (38) assert?Asserts: The present King of France is bald

We will say more later about how to distinguish asserted content from presuppositional content.

Some are adverbs:

39. Bill failed the test again

40. Bill failed the test too

What does (39) assert?Bill failed the testWhat does (39) presuppose?He had failed the test beforeWhat does (40) assert?Bill failed the testWhat does (40) presuppose?Somebody in addition to Bill failed the test

Some presupposition triggers are constructions:

41. It is Miranda who broke the computer

Presupposes: 42. Somebody broke the computer

Asserts:43. Miranda broke the computer

So, presuppositions are inferences which

• survive questions• survive negation• have to be true for the sentence that contains

them to have a truth-value

But why should these properties pattern together?And there is one more property that is considered basic about presuppositions (and gives them their name):

When we utter a sentence that has presuppositions, the presuppositions are not part of the new information we want to convey. Instead, we take the presuppositional content as already known.

This helps us determine what the assertion and what the presupposition of the utterance is

For example, when I tell you

38. The present king of France is bald

The new thing that I am telling you is not that there is a king of France. I am presupposing that you know that.The new information that I want to give you is that this person is bald.

39. Bill failed the test again

40. Bill failed the test too

Similarly, when I tell you (39), I am assuming you already know that Bill failed the test once before.When I tell you (40), I am assuming you already know that somebody other than Bill failed the test.

So, when I tell you:

44. My brother gave me this watch

I am presupposing that I have a brother.What I am asserting is that he gave me this watch.

But does this seem correct?

Can’t I tell you

44. My brother gave me this watch

if you don’t know that I have a brother?

For sure I can!

But my having a brother is still expressed as a presupposition in (44).How can we express something as a presupposition even if its truth is not taken for granted by the interlocutors?

The hearer accommodates the presupposition.

“If at time t something is said that requires presupposition P to be acceptable, and if P is not presupposed just before t, then –ceteris paribus and within certain limits– presupposition P comes into existence at t”

David Lewis 1979: “Scorekeeping in a language game” Journal of Philosophical Logic 8(1):339-359.

Presuppositions

• survive questions• survive negation• have to be true for the sentence that contains

them to have a truth-value• are taken for granted by the interlocutors or

accommodated by the hearer(s)

Why should these properties cluster together?

Two more basic notions for today

In a previous slide we talked about sentences having truth-conditions.Let’s improve on that a bit.

Let’s call a ‘sentence’ any constituent of the syntactic category IP.

We defined ‘assertion’ as the act by which one commits oneself to the truth of the sentence uttered.

A sentence that makes an assertion, expresses a ‘proposition’.

(some think of a proposition as the “thought” expressed by a sentence)

It is propositions that are true or false.(not sentences)

Let’s keep the two notions separate:

• Some, not all, sentences express a proposition. For example, questions and commands are sentences but they do not express propositions

• Two different sentences can express the same proposition:

45. The cheetah killed the gazelle 46. The gazelle was killed by the cheetah

• Two different sentences in different languages can express the same proposition:

47. The cheetah killed the gazelle48. Гепард убил газель

• A sentence can express a different proposition depending on the context it is uttered in.

49. I am wearing a hat right now

Sentence (49) expresses a different proposition depending on• -who is uttering it.• -when it is being uttered.

• So propositions and sentences are not the same thing.

Even so, we often speak sloppily and talk about sentences having truth-values etc.

So sentences are linguistic objects.

A common way of thinking of propositions is as a set of possible worlds, specifically, those worlds in which the proposition holds/is true.

Why a plurality of worlds?Let us say that (50) is true.

50. The instructor talking right now is wearing glasses

Imagine a world in which (50) is true and (51) is also true:

51. It is raining right now in Bejing

w1: The instructor is wearing glasses It is raining in Bejing

But we can also have w2:

w2: The instructor is wearing glasses It is not raining in Bejing

Do you know which world we are in?

And of course, there are infinitely many ways to describe a world. Just add one more sentence:

52. The number of people in the building right now is odd

Before we had two possible worlds:

w1: The instructor is wearing glasses It is raining in Bejing

w2: The instructor is wearing glasses It is not raining in Bejing

Now we have 4 possible worlds:

w3: The instructor is wearing glasses It is raining in Bejing The number of people in the building right now is odd

w4: The instructor is wearing glasses It is raining in Bejing The number of people in the building right now is not odd

w5: The instructor is wearing glasses It is not raining in Bejing The number of people in the building right now is odd

w6: The instructor is wearing glasses It is not raining in Bejing The number of people in the building right now is not odd

In all these worlds, it is true that the instructor is wearing glasses. This is why a proposition corresponds to the set of worlds in which it is true.