Presuppositions (and Focus)
Sabine Iatridou
What does it mean to understand (the
meaning of) a sentence?
• Do you understand this sentence?
1. The instructor of this class is wearing glasses
Is it true?
Yes.
Do you understand this sentence?
2. The instructor of this class is wearing pink a hat
Is it true?
No.
2
• What about this sentence:
3. It is raining in Beijing right now
Is 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.
3
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?
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
5
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 vodka
But even if (6) is false, it still entails (7) and (8):
7. Half of MIT students have tried horseradish
vodka
8. All the students in my syntax class at MIT have
tried some type of vodka
6
• 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?
7
• 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 demonstrator
12. 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.
8
Further inferences
13. Chris believes that gombats futter bravely
14. 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 wrong
c. #Chris realized that gombats futter bravely,
but I do not know if they do
17. Chris believes that the earth is flat
18. 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 children
this 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 children
S2: 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
Chris realized that gombats
futter bravely
Did Chris drink vodka and eat
serniki?
≠>
Chris drank vodka
Did Chris realize that gombats
futter bravely?
=>
Gombats futter bravely
Chris did not drink vodka and
eat serniki
Chris did not realize that
gombats futter bravely
≠>
Chris drank vodka
=>
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 bravely
presupposes
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 France T
But negating (36) does not yield a true sentence:
36. Chris realized that London is the capital of France
37. 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 test
What does (39) presuppose?
He had failed the test before
What does (40) assert?
Bill failed the test
What 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):339359.
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 gazelle
48. 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.