Kaplan and two-dimensionalism
(The following is adapted from Laura Schroeter’s article “Two-Dimensional Semantics”)
"We can think of contexts as what David Chalmers calls ‘centered worlds.’ A centered world is a world, an agent within that world, and a time when the agent exists or utters something within that world <w, a, t>"
(The following matrices are adapted from Robert Stalnaker)
Trump’s use of ‘I’ in his inaugural address:
w1
|
w2
|
w3
| |
⟨w1,DT,t0⟩
|
DT
|
DT
|
DT
|
The leftmost column represents context
The top row represents the world that takes us to an assessment of the utterance
Left is context of utterance
Top row is circumstance of evaluation
So, evaluating Trump’s use of ‘I’ in w1 requires that we keep the referent of ‘I’ fixed when we plug in w2 and w3. So, ‘I’ is very much like a rigid designator.
In other words, possible worlds get appealed to twice—once at the level of character—and once again at the level of content.
Character: w1 in <w1, DT, t0> is the relevant context of use (in this case, the use of the expression ‘I’) and once this gets plugged in, the content of the expression can be determined from various circumstances of evaluation.
Content: the circumstances of evaluation (the top row) allow us to assess the content of the utterance from various vantage points—different possible worlds. As you can see, each circumstance of evaluation yields the same value—namely, DT. So, once the character is fixed by the context, the content of ‘I’ yields the same referent.
Kaplanian character of ‘I’:
w1
|
w2
|
w3
| |
⟨w1,DT,t0⟩
|
DT
|
DT
|
DT
|
⟨w2,BS,t0⟩
|
BS
|
BS
|
BS
|
⟨w3,HRC,t0⟩
|
HRC
|
HRC
|
HRC
|
Left column: context of use (character is a function from context to content)
Top Row: circumstance of evaluation (Content is a function from possible world to truth value or semantic value more generally)
Kaplanian character of ‘the inaugural speaker in 2016’:
w1
|
w2
|
w3
| |
⟨w1,DT,t0⟩
|
DT
|
BS
|
HRC
|
⟨w2,BS,t0⟩
|
DT
|
BS
|
HRC
|
⟨w3,HRC,t0⟩
|
DT
|
BS
|
HRC
|
Do you see how the character (and the content) of ‘the inaugural speaker in 2016’ differs from the character (and the content) of ‘I’?
When the context is fixed (the left column), the content of the expression yields a different individual (the extension varies) depending on the circumstance of evaluation. Since in w2 Bernie Sanders is the inaugural speaker (see the context side), when the circumstance of evaluation is w2 (top row), Donald Trump’s use of the expression ‘the inaugural speaker’ in w1 picks out Bernie Sanders.
When you and I discuss how it is possible that the inventor of bifocals was Thomas Jefferson, we are uttering the expression ‘the inventor of bifocals’ from our world (w1) and evaluating it (determining it’s content or extension) from w2. Since in w2 Thomas Jefferson invents the bifocal, w2 represents Jefferson as the value of the expression.
Kaplanian character of ‘Donald Trump’:
w1
|
w2
|
w3
| |
⟨w1,DT,t0⟩
|
DT
|
DT
|
DT
|
⟨w2,BS,t0⟩
|
DT
|
DT
|
DT
|
⟨w3,HRC,t0⟩
|
DT
|
DT
|
DT
|
This is as it should be since ‘Donald Trump’ is an RD.
No matter the context of use (left column) the content of the expression ‘Donald Trump’ yields the same semantic value, namely, Trump himself.
Assume Trump would attend the inaugural address of Sanders but not of Clinton, Sanders would avoid the inauguration of anyone who defeated him, and Clinton would attend Sander’s inauguration but not Trump’s.
Kaplanian character of ‘I am here’
w1
|
w2
|
w3
| |
⟨w1,DT,t0⟩
|
T
|
T
|
F
|
⟨w2,BS,t0⟩
|
F
|
T
|
F
|
⟨w3,HRC,t0⟩
|
F
|
T
|
T
|
Look at the various ‘Fs’: They represent the fact that the utterance of ‘I am here’ is contingent. I did not have to be here right now. I could have been somewhere else, and thus ‘here’ would have picked out a different location. So, Trump’s utterance of ‘I am here’, where ‘here’ picks out the inaugural address turns out to be false in w3 since he would not have attended Clinton’s inaugural address.
The content of the expression ‘I am here’ given the context <w1, DT, t0> is that Trump is in DC on Jan 21, 2016. Since he is not in DC on Jan 21 in w3, the expression is false.
In other words, we want our semantics to conform to the fact that it is possible that I (the speaker) am not here (this particular location). It better not turn out that our semantics entails that ‘I am here’ is a necessary truth. If it did, then the speaker would be a necessary being and the location would be a necessary place. But that is either (a) not true at all, or (b) if it is true, it should not be entailed by the semantics but rather by lots of argument.
Look at the diagonal: ‘I am here’ is true whenever it is uttered. For every possible context, the sentence will be true at the world of that context. When we focus on the context—the world where DT, BS, or HRC is speaking—the utterance always comes out true according to that world. So, where BS is the speaker and the world is one where he is at the inauguration, the utterance is true.
This is supposed to be an instance of an apriori contingent truth. It is controversial, but the cool thing here is that 2D semantics seems to get the semantics of it right, even if the epistemology and metaphysics is controversial. So, 2D semantics allows us to do what it seems we should be able to do at least partially, namely, provide a semantics for a language that is as epistemically and metaphysically neutral as possible.
Of course, it is not completely neutral. All sorts of assumptions are at work, but the hope is that these assumptions are the most minimal and innocent—every plausible semantics will have to have them.
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