Transcript PowerPoint

CAS LX 502
Semantics
8b. Propositional attitudes
7, 9
Propositional attitudes
The door is
 I think Pavarotti is hungry.
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We discussed the morning star is the
evening star
Bond is hungry
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Bond is hungry.
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A proposition.
Either true or false,
relative to a given
situation.
A sentence.
Language has the
capacity to embed
one sentence within
another.
I think/hope/heard
Bond is hungry.
Bond is
hungry
Bond is
not hungry
I think Bond is
hungry
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The natural thing to
suppose about
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I think/hope/heard
Bond is hungry.
is that the sentenceembedding verbs think
etc. relate the thinker
(Experiencer) to a
proposition.
Bond is hungry need not
be true for I think Bond is
hungry to be true. It’s just
that worlds compatible
with my beliefs are those
in which Bond is hungry.
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(The actual world need not
be within the worlds
compatible with my
beliefs.)
Bond is
hungry
Bond is
not hungry
I think Bond is
hungry
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That is:
I think Bond is hungry is
true in any world w in
which my beliefs in world
w are such that any
world I believe is a
candidate for the actual
world is also a world in
which Bond is hungry.
That seems pretty
straightforward— except
what do we make of a
sentence like:
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I believe that 1+1=2.
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Bond is
hungry
Bond is
not hungry
I think 1+1=2
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Well, 1+1=2 is true all the
time.
Point one:
This is kind of contentless.
Point two:
1+1=2 is true in all the
same worlds that
12345x67890=838102050
is. So it must also be true
that I think 12345 x 67890
= 838102050.
In fact, everyone must
think both of these
things, as well as any
other mathematical
truth.
I think 1234x67890=8.
I think 1=0.
1+1=2
I think 1+1=2
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We’ve reached a rather
hard problem.
A similar one:
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Pat wants to marry Lynn.
Pat wants to marry Chris.
If want does something
like set up a relation
between Pat and the set
of worlds in which Pat’s
desires are met, one
must be true while the
other is false (if we
presuppose that the two
are mutually exclusive).
1+1=2
Where to go from here?
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Another case Portner mentions:
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I think 1+1=2.
I think 12345x67890=838102050.
Pat wants to marry Chris.
Pat wants to marry Lynn.
Day-care provider: Noah cries all the time.
Grandmother: Weihan is perfectly behaved.
Trusting hearer: I accept your statements.
Unbenownst to TH: Noah and Weihan are the same
kid.
Ideas?
My guess
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This is a literature that I am not that familiar
with, so I don’t know what the philosophers
have said about it.
However.
Clearly, we need to differentiate between:
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I think 12345x67890=838102060.
I think dogs are not dogs.
The pathological case is the first one.
Perhaps it is a failure of reference, which
might also be able to capture the
Noah/Weihan case as well.
My guess
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Noah refers to a baby. Weihan refers to a
baby.
If I use Weihan to refer to a different baby
than I use Noah to refer to, then I have one
of the names wrong.
It seems possible, though, that one can
have names wrong.
Given that, perhaps we can make
headway with the math question by
supposing that it’s possible to get the names
wrong there too…
My guess
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Tracy believes that 4+5=9 and 4x5=23.
There’s a sense in which Tracy doesn’t
“understand” multiplication.
Tracy believes that “x” is a (ditransitive) verb
that relates 4, 5, and 23. There could be such
a verb. It’s just not what mathematicians
refer to as “x”. But it’s the verb Tracy uses,
and named “x”.
Then, it is not necessarily true that if Tracy
believes that 4x5=23, Tracy also believes that
4x5=22.
If we insist that everything is a name, …?
My guess
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There is a certain flexibility with names
anyway in intensional contexts…
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I dreamt that I was Prince Charles and you were
Harry Potter and we were in a leaky canoe, trying to
return a wayward capybara to its birth parents.
Perhaps a proposition
carries not only
information about truth
conditions but also
information about F
(the naming function)?
De re vs. de dicto
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Trying again: de re vs. de dicto:
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Premise: Essentially a drawn-out game show
where players work as a team to win money,
but one is a plant there to foil their efforts.
De dicto belief: belief about description.
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Pat thinks that the mole is wearing a green shirt.
Pat thinks whoever the mole is, s/he is wearing a
green shirt.
De re belief: belief about individual(s).
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Pat thinks Chris is wearing a green shirt.
Chris happens to be the mole.
De re vs. de dicto
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De dicto: The mole is part of Pat’s thought.
De re: The mole is not part of Pat’s thought, but of
my assertion.
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Tracy claimed Pat thinks that the mole is wearing a green shirt.
The mole: my assertion
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Pat thinks that the mole is wearing a green shirt.
Chris is wearing a green shirt
Thinks Pat
According to Tracy
The mole: Tracy’s statement
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Lynn is wearing a green shirt
Thinks Pat
According to Tracy, who claims the mole is Lynn. But it’s Chris.
De re vs. de dicto
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This seems to arise from the relativization to
another possible reality, belief worlds,
thought worlds, dream worlds.
Substitution is possible where the referents
are the same in the reality under evaluation.
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Pat thinks Chris is wearing a green shirt.
Pat thinks the mole is wearing a green shirt.
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Same if in Pat’s belief worlds Chris and the mole have the
same referent. (de dicto)
Same if in reality, Chris and the mole have the same referent.
(de re)
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