Today, we look askance at the word "content". What is this term, from philosophy of mind, doing in our semantic theorizing? We are not sure; our suspicions are roused.
Yet Prof. MacFarlane talks at length about content in "Nonindexical contextualism," where he argues for the existence and viability of a view on which epistemic operators are context-sensitive without being indexical. Translation into our suspect terminology: an epistemic standard parameter may play a circumstance-determinative role without playing a content-determinative role in our semantics.
From his discussion, the following, at least, are clear about content:
*the content of a sentence-at-a-context is intuitively identified with a proposition
*sentences with indexicals express different propositions (hence, have different contents) at different contexts.
*the content of a sentence determines its truth-value at a context of use.
...From this, it seems that the right thing to conclude is that content of a sentence-at-a-context is just its semantic intension. All the indexicals are, so to speak, "filled in", but the the resulting intension has not yet been evaluated at the circumstance of the context, so the intension has not yet been reduced to an extension (either T or F.)
Another way to get a bead on content, suggested by MacFarlane's discussion, is to look at the dispute between Temporalism and Eternalism. For Eternalists, the time of the context gets into the content of tensed sentences like "Socrates is sitting":
"On the Eternalist's view, the sentence ["Socrates is sitting"] varies in truth-value across times because it expresses different propositions at different times." (4)
This suggests the following gloss on the difference between Eternalism and Temporalism in terms of semantic values:
(Temp) [[Socrates is sitting]]^c_{\varnothing}* = \lambda w. \lambda t. Socrates is sitting in w at t
(Eter) [[Socrates is sitting]]^c_{\varnothing} = \lambda w . \lambda t . Socrates is sitting in w at t_c.
...hence on this view what it means for the Eternalists and Temporalists to disagree about what proposition "Socrates is sitting" expresses is for them to disagree on the intension of the sentence. Behold the "t_c" in the Eternalist's semantic entry; this is an indexical, just as "speaker_c" would be the meaning of "I" or "loc_c" would be the meaning of "here." So, on this entry, the Eternalist just thinks that "Socrates is sitting" is synonymous with "Socrates is sitting now."
What I find confusing about this is that I am unable to give a proper semantic entry for temporal operators on the eternalist's view. "Socrates is sitting" does NOT behave like "Socrates is sitting now" in that, of course, [[It will always be the case that Socrates is sitting]] is not the same as [[It will always be the case that Socrates is sitting now.]] Any eternalist view must account for this difference; the Eternalist cannot be so easily refuted as that!
...He must account for it in the same way that a possible worlds theorist accounts for the intuitive truth conditions of "Snow is white" as opposed to "Snow is actually white." He must hold that unembedded assertions like "Snow is white" are as a default evaluated at the world of the context, but that they are still shift-able in the scope of modal operators. I can see two ways to do this. One is to mimic, for our intuitive notion of content, the semanticists intensional type-lift: hold that content is usually extension, unless it is *forced* to be intension by the presence of a model operator. Hence: an unembedded "snow is white" utterance is true if snow is white in w_c, yet the contribution "snow is white" makes in the scope of modal operators does not refer us back to w_c.
The problem with this is that it makes nonsense of the other things MacFarlane says about content. For example, he says of the sentence "tomorrow comes after today" that it expresses different contents at different contexts, while having the same truth-value at every context. However, if the content of an unembedded expression is its EX-tension, then it cannot vary in this way.
The only other way I can see is to hold that content is what Prof. Yalcin calls "centered diagonal content", where this is lambda-abstraction over the c parameter. Hence:
(Temp) [[Socrates is sitting]]^wt_{\varnothing}** = \lambda c. Socrates is sitting at w_c
(Eter) [[Socrates is sitting]]^wt_{\varnothing} = \lambda c . Socrates is sitting at w_c and t_c.
Note once again the absence of t_c from (Temp). What, now, would the difference between (Temp) and (Eter) come to? Almost nothing, which is, perhaps, the point...It seems only to support the following intuition:
"If I had said "Socrates is sitting" at another time, it would have expressed a different content."
...this is true for (Eter) and not for (Temp). These creatures, (Eter) and (Temp), are NOT the arguments of temporal operators. What *are* the intensions on this view? It must be...
(Temp) [[Socrates is sitting]]^c_{\varnothing} = \lambda w . Socrates is sitting in w
(Eter) [[Socrates is sitting]] ^c_{\varnothing} = \lambda w . \lambda t . Socrates is sitting in w at t
Now this is pretty odd. On this version of temporalism, sentence truth looks like this:
A sentence s is true at a context c iff [[S]] is true at w_c and t_c. [hence there need be no temporal content "in" S.]
(A sentence s is true at a context c iff the proposition expressed by S is true when evaluated at the circumstance of C. = (25), pg. 21.)
And temporal operators look...metalinguistic, I guess, like this:
[[ALWAYS \phi]]^cwt = \lambda w . \forall c' s.t. w_c' = w_c, [[\phi]] expresses a truth at the circumstance determined by c; [[\phi]]^w_c, t_c is true.
...this view looks very strange to me, though we should note of an analogous move for epistemic standard parameters it is widely conceded that there *are* no shifters. The arguments in favor of such a view must mostly be content-based ones in the phil-mind sense, because semantically speaking, it's ugly.*** (Perhaps the right thing to say about this ugliness is that we are simply no longer speaking about any kind of semantic value or anything straightforwardly derivable from a semantic value.)
Here is such a consideration: the propositions we believe (= the contents of sentence at a context) intuitively don't determine truth "all by themselves." Sam believes it is 0 degrees--is that belief true or false? Well, we don't know until we know the time and place his belief 'concerns'. We also need to know what world he's in, and intuitively his belief isn't about worlds:
"One might respond to these considerations by bringing the world of the context of use into the *content* of Sam's thought. But intuitively, Sam could have had a thought with the same content even if the world had been very different." (16)
According to Temporalism, both worlds and times play a circumstance- but not content-determining role. For Eternalism, times play a content-as-well-as-circumstance determining role. Yet I am puzzled about how to make this work in the formal semantics, because I am puzzled by how content is supposed to interact with intensions. We have a good argument that intensions must have an *open* (hence shiftable) time-parameter, but whether this legislates that time does not play a content-determining role depends on what the relationship between intensions and contents is. In the epistemic standards case, once it is conceded that there are no shifters, we don't need an open (hence shiftable) time-parameter in the intension. Perhaps we don't need one *at all*, and it is this that nonindexical contextualism amounts to. The difference then would not be between a *free* t-parameter and a [contextually] *bound* t-parameter, but rather a difference between a [contextually] *bound* e-parameter and...no e-parameter at all.
******
*e.g., the intension of the sentence, rather than the extension. (Following Heim and von Fintel.) Note the index here comprises world-time ordered pairs.
**Generalizing the pattern to mean abstraction over c but not w and t? Probably this is abuse of notation.
***Note that this won't work for the world parameter anyway, for familiar reasons: it is not sufficient for the truth of the sentence "necessarily p" that p express a truth at every context.
*******
MacFarlane, J. "Nonindexical Contextualism." Synthese 166, 2009.
Yalcin, S. "Notes on semantics, context, and content". Handout at UC Berkeley for Phil 290-5, 9/16/2010.
Tuesday, September 21, 2010
Thursday, September 16, 2010
Writing about...
Instead of blindly trying to edit my paper by asking myself if I agree with every individual sentence, I've decided to step back and remind myself what I'm trying to accomplish. This could get rocky!...Hang on!...
When we talk about the contents of a perceptual experience, we assign to it a kind of abstract entity, a function from situations to truth-values, which is very much like the kind of abstract entity we assign to a meaningful, well-formed sentence (occurring at a context). When we do this, we assign to perceptual experiences Lewis [1980]'s "first job" for semantic values: determining a truth-value at a context.
However, a big difference with giving semantics for sentences is immediately apparent: perceptual experiences don't have meaningful *parts.* So we cannot give ourselves the compositional project of accounting for the content of the whole experience in terms of the contents of the parts. There is no analogue, for theorizing about perceptual content, of the constraints that compositionality imposes on our semantic theorizing "from below": we just don't know what it would *mean* to give a theory of content for the whole of a perceptual experience by giving a theory of content for the experience's parts, because, er, experiences don't *have* parts in the same way that sentences do. Or at least, *if* they do, this would come as a big fat surprise to me.
We can say that the need for a compositional theory of language is grounded in the bald fact about our language that it consists of sentences which are s.t. the meaning of the whole supervenes on the meanings of the parts. Yet it is worth noting that this is not the way compositionality is usually argued for. The argument is usually put in terms of our *knowledge* of our language: we say that we need a compositional theory for our language because we observe that knowledge of the parts of a well-formed sentence is sufficient for knowledge of the meaning of a novel combination of those elements. (This is what Prof. Yalcin calls the "productivity" of our linguistic knowledge.) I am somewhat confused here as to whether there is a genuine difference in views; presumably our knowledge is productive because our language is productive, and our language is productive because our knowledge of it is productive. Perhaps there is no genuine difference here, just two different ways of putting the point. The first way is to make the compositionality of language sound like a *metaphysical* truth: the meaning of our language just *is* s.t. the meanings of whole sentences is determined on the meanings of their parts. Hence the meanings of the parts are metaphysically sufficient for determining the meanings of new wholes constructed out of those parts. The second way to look at it is as an *epistemic* truth: it turns out to be true of us that we can understand novel sentences whenever we have prior "acquaintance" with their parts. Hence, if we are giving a theory which is supposed to capture (not just the nature of our language but) the nature of OUR KNOWLEDGE of our language, the theory should account for this fact. It would be compatible with such a theory, and such an outlook on the constraint of compositionality, that other creatures with other epistemic habits could speak the SAME language as we do, yet not be "productive" consumers of the language in the same sense that we are. Is this really possible?...I am inclined to feel rather skeptical that this is possible. So to the extent that the two views of compositionality come apart, I am more sympathetic towards the "metaphysical" view.
We return to the nature of perceptual experiences, and the project of assigning them content. We have just come from the observation that we cannot go, as it were, below the level of the whole representational experience, to assign content to its proper parts (upon which the content of the whole will then metaphysically-cum-epistemically supervene.)* But that's okay...after all, that part of compositionality is not even what Lewis is interested in. He is interested in compositionality "from above": on the constraint imposed by the fact that well-formed sentences compose with sentential operators. The question becomes: what (how complex a) semantic value must we assign to the argument-sentence so that this semantic value is sufficient for determining the semantic value whole sentence? It turns out--famously...--that the semantic value must include things that are not in (and not recoverable from) the set of all contexts. This is the set of possible indices.
Now, the analogy I am pursuing in the paper, which is only a partial analogy, is this: although there are ALSO no "experience operators" around for philosophers of perception to talk about, there *is* something quite similar: there are distinct phenomenal states which the content of perceptual experience can interface with. One of these is imagination. Another is memory. Perhaps yet a further one is premonition...who knows?
What is this like, in the philosophy of language?
Well, it's really more like giving a theory of content for representational mental states, rather than sentences. One and the same content can be both believed and supposed (maybe entertained as possible, even, where this is a separate state.) We want to seek this thing, the content, which can be both believed and supposed, so that we intuitively get right what belief and supposition have in common and how they differ.
One oft-proposed connection between content qua representational mental states and philosophy of language is giving a semantic account of *what is said* (which might or might not be identical with giving a semantics for the verb "said that.") Roughly, the idea is that what you say expresses what you believe, and that is just the semantic value of your sentence evaluated at the context of your believing/uttering. The context will play two roles: it will initialize the index (to wit, it is the index of the context that will determine whether the sentence is true or false) and it will fix the extension of indexical terms.
Upshot: maybe our project is like giving an account of what is said/what is believed. What this means is that we may not need an index as well as a context.
Here are two arguments meant to push us to the "index too" conception:
1) Indexicals have semantic values which are sensitive to context. But indexicals don't shift in the scope of modal operators.
I don't think this consideration is relevant either to the language case OR (a fortiori...) to the representational state case. We could just say that indexicals are rigid designators. So while they're sensitive to context for their semantic values, the semantic values don't shift. This could be implemented in several ways. We could restrict the accessibility relation on other contexts. We could define an intermediate notion of 'contextual proposition', where all the values for the indexicals were fixed, and then quantify over whatever remained in the scope of the operator (this would be the equivalent of giving the indexicals widest scope.)
2) There are cases in which the compound sentence you get from intensional operator + sentence just doesn't seem to have the truth-conditions you would get if the intensional operator quantified over contexts. For example, "It might have been that I am not here now." That is true, even though "I am here now" is true in every context. This, it seems to me, is what genuinely makes the case for independently shiftable indices. Note that the argument will go through with an indexical-ridden sentence like "I am here now" even if we took the indexicals to be rigid designators across contexts: all this would mean is that in the scope of the modal operator, "I" always refers to the speaker of the original context, "here" always refers to the location of the original context, and "now" always refers to the time of the original context. In such a language, for example, "I might have been male" isn't made true because a man might have said it; the only contexts quantified over are contexts where the original speaker is still the speaker of the context. So "I might have been male" is false. Nontheless, "I might not have been here" is still true.
While I think this is the right argument for the language case, this argument does not generalize to the perception case, because as we said, there is no analogue of an intensional operator. So my verdict is that so far the "we must have index as well as context!" claim does not go through.
Could an argument from supposing, considered as an attitude taking a propositional complement, be sufficient to overthrow this conception?
...It might be, depending on what we take supposing to be. It seems that supposing can shift individual indices (= individual features of context). We can suppose that I am not here. (I do this all the time, by way of supposing I am elsewhere.) We can suppose it's raining but we don't believe it is. We can suppose that Hesperus is not Phosphorus, for that matter. We can suppose many things which are (i) not true in any context, and furthermore (ii) not true at any index (though we'll leave that one aside for now.) Perhaps this is identical with the attitude of pretense.
An argument that we need more than just contexts to represent the contents of our attitudes of supposing would have to proceed from a variation on the second type of argument. If it just seems like an appeal to intuition, that might be ok with me...it seems like a pretty *strong* appeal to intuition! It would just be to say: can you suppose you're not here? And the answer is just: yes. What is a bit unsatisfying about the dialectic of my paper is that this is precisely what my interlocutors deny. How to respond?...well, I guess my intuitive response is that they don't really believe this on the basis of intuition; they are in the grip of a theory. So the task shifts to explaining why the theory is wrong, which is sort of complicated. In that discussion, it seems like my initial advantage is somehow lost, for want of emphasis.
If we want to put non truth-apt supposings in the form of sentences with different truth values, the nearest analogue seems to be the antecedent of a conditional. Suppose p; is q true? This is just: is it true that p->q? So a way to show that you needed indices as well as contexts here would be to find two sentences p and q that did not differ in their truth-at-a-context profile: whenever p is true at a context, q is true at that context, and vice-versa. Yet we could try to find a sentence r that followed from the former but not the latter. That would show that p was contributing more to the evaluation of the conditional than just a set of contexts where it is true.
Suppose p; is r true? (yes)
Suppose q; is r true? (no)
For this strategy, we could use p = "I exist", and q = "I am here."
If I am here, then I am not there. (True)
If I exist, then I am not there. (False)
My method was another common one: just take p to be "I am not here." Since this is true in no context, every conditional with p as an antecedent should sound the same: either all trivially true or all uninterpretable (or whatever, given our theory of conditionals). The point is that there shouldn't be possible to find an A and a B such that "if p, A" strikes us as true while "if p, B" strikes us as false.
Let's try to see exactly how Lewis makes the point. Is it just a bald appeal to intuition? He considers sentences like
"If someone is speaking here then I exist." (True)
"Forevermore, if someone is speaking here then I will exist." (False)
NB The argument works as an appeal to intuition, but only because we are actually assuming that "If someone is speaking here then I exist" is true, and this is only because we haven't taken the more restricted view of indexicals. Clearly, "If someone is speaking in the Dennes Room then Melissa exists" is not true; my existence does not depend on whether people continue to talk in the Dennes Room. However, other cases could be constructed, as above.
****
It has just occurred to me that this might in fact be possible, and the way of explaining e.g. Escher staircase experiences of the type that interest Susanna Siegel...
Siegel, Susanna (2004). Indiscriminability and the Phenomenal. Phil. Studies.
When we talk about the contents of a perceptual experience, we assign to it a kind of abstract entity, a function from situations to truth-values, which is very much like the kind of abstract entity we assign to a meaningful, well-formed sentence (occurring at a context). When we do this, we assign to perceptual experiences Lewis [1980]'s "first job" for semantic values: determining a truth-value at a context.
However, a big difference with giving semantics for sentences is immediately apparent: perceptual experiences don't have meaningful *parts.* So we cannot give ourselves the compositional project of accounting for the content of the whole experience in terms of the contents of the parts. There is no analogue, for theorizing about perceptual content, of the constraints that compositionality imposes on our semantic theorizing "from below": we just don't know what it would *mean* to give a theory of content for the whole of a perceptual experience by giving a theory of content for the experience's parts, because, er, experiences don't *have* parts in the same way that sentences do. Or at least, *if* they do, this would come as a big fat surprise to me.
We can say that the need for a compositional theory of language is grounded in the bald fact about our language that it consists of sentences which are s.t. the meaning of the whole supervenes on the meanings of the parts. Yet it is worth noting that this is not the way compositionality is usually argued for. The argument is usually put in terms of our *knowledge* of our language: we say that we need a compositional theory for our language because we observe that knowledge of the parts of a well-formed sentence is sufficient for knowledge of the meaning of a novel combination of those elements. (This is what Prof. Yalcin calls the "productivity" of our linguistic knowledge.) I am somewhat confused here as to whether there is a genuine difference in views; presumably our knowledge is productive because our language is productive, and our language is productive because our knowledge of it is productive. Perhaps there is no genuine difference here, just two different ways of putting the point. The first way is to make the compositionality of language sound like a *metaphysical* truth: the meaning of our language just *is* s.t. the meanings of whole sentences is determined on the meanings of their parts. Hence the meanings of the parts are metaphysically sufficient for determining the meanings of new wholes constructed out of those parts. The second way to look at it is as an *epistemic* truth: it turns out to be true of us that we can understand novel sentences whenever we have prior "acquaintance" with their parts. Hence, if we are giving a theory which is supposed to capture (not just the nature of our language but) the nature of OUR KNOWLEDGE of our language, the theory should account for this fact. It would be compatible with such a theory, and such an outlook on the constraint of compositionality, that other creatures with other epistemic habits could speak the SAME language as we do, yet not be "productive" consumers of the language in the same sense that we are. Is this really possible?...I am inclined to feel rather skeptical that this is possible. So to the extent that the two views of compositionality come apart, I am more sympathetic towards the "metaphysical" view.
We return to the nature of perceptual experiences, and the project of assigning them content. We have just come from the observation that we cannot go, as it were, below the level of the whole representational experience, to assign content to its proper parts (upon which the content of the whole will then metaphysically-cum-epistemically supervene.)* But that's okay...after all, that part of compositionality is not even what Lewis is interested in. He is interested in compositionality "from above": on the constraint imposed by the fact that well-formed sentences compose with sentential operators. The question becomes: what (how complex a) semantic value must we assign to the argument-sentence so that this semantic value is sufficient for determining the semantic value whole sentence? It turns out--famously...--that the semantic value must include things that are not in (and not recoverable from) the set of all contexts. This is the set of possible indices.
Now, the analogy I am pursuing in the paper, which is only a partial analogy, is this: although there are ALSO no "experience operators" around for philosophers of perception to talk about, there *is* something quite similar: there are distinct phenomenal states which the content of perceptual experience can interface with. One of these is imagination. Another is memory. Perhaps yet a further one is premonition...who knows?
What is this like, in the philosophy of language?
Well, it's really more like giving a theory of content for representational mental states, rather than sentences. One and the same content can be both believed and supposed (maybe entertained as possible, even, where this is a separate state.) We want to seek this thing, the content, which can be both believed and supposed, so that we intuitively get right what belief and supposition have in common and how they differ.
One oft-proposed connection between content qua representational mental states and philosophy of language is giving a semantic account of *what is said* (which might or might not be identical with giving a semantics for the verb "said that.") Roughly, the idea is that what you say expresses what you believe, and that is just the semantic value of your sentence evaluated at the context of your believing/uttering. The context will play two roles: it will initialize the index (to wit, it is the index of the context that will determine whether the sentence is true or false) and it will fix the extension of indexical terms.
Upshot: maybe our project is like giving an account of what is said/what is believed. What this means is that we may not need an index as well as a context.
Here are two arguments meant to push us to the "index too" conception:
1) Indexicals have semantic values which are sensitive to context. But indexicals don't shift in the scope of modal operators.
I don't think this consideration is relevant either to the language case OR (a fortiori...) to the representational state case. We could just say that indexicals are rigid designators. So while they're sensitive to context for their semantic values, the semantic values don't shift. This could be implemented in several ways. We could restrict the accessibility relation on other contexts. We could define an intermediate notion of 'contextual proposition', where all the values for the indexicals were fixed, and then quantify over whatever remained in the scope of the operator (this would be the equivalent of giving the indexicals widest scope.)
2) There are cases in which the compound sentence you get from intensional operator + sentence just doesn't seem to have the truth-conditions you would get if the intensional operator quantified over contexts. For example, "It might have been that I am not here now." That is true, even though "I am here now" is true in every context. This, it seems to me, is what genuinely makes the case for independently shiftable indices. Note that the argument will go through with an indexical-ridden sentence like "I am here now" even if we took the indexicals to be rigid designators across contexts: all this would mean is that in the scope of the modal operator, "I" always refers to the speaker of the original context, "here" always refers to the location of the original context, and "now" always refers to the time of the original context. In such a language, for example, "I might have been male" isn't made true because a man might have said it; the only contexts quantified over are contexts where the original speaker is still the speaker of the context. So "I might have been male" is false. Nontheless, "I might not have been here" is still true.
While I think this is the right argument for the language case, this argument does not generalize to the perception case, because as we said, there is no analogue of an intensional operator. So my verdict is that so far the "we must have index as well as context!" claim does not go through.
Could an argument from supposing, considered as an attitude taking a propositional complement, be sufficient to overthrow this conception?
...It might be, depending on what we take supposing to be. It seems that supposing can shift individual indices (= individual features of context). We can suppose that I am not here. (I do this all the time, by way of supposing I am elsewhere.) We can suppose it's raining but we don't believe it is. We can suppose that Hesperus is not Phosphorus, for that matter. We can suppose many things which are (i) not true in any context, and furthermore (ii) not true at any index (though we'll leave that one aside for now.) Perhaps this is identical with the attitude of pretense.
An argument that we need more than just contexts to represent the contents of our attitudes of supposing would have to proceed from a variation on the second type of argument. If it just seems like an appeal to intuition, that might be ok with me...it seems like a pretty *strong* appeal to intuition! It would just be to say: can you suppose you're not here? And the answer is just: yes. What is a bit unsatisfying about the dialectic of my paper is that this is precisely what my interlocutors deny. How to respond?...well, I guess my intuitive response is that they don't really believe this on the basis of intuition; they are in the grip of a theory. So the task shifts to explaining why the theory is wrong, which is sort of complicated. In that discussion, it seems like my initial advantage is somehow lost, for want of emphasis.
If we want to put non truth-apt supposings in the form of sentences with different truth values, the nearest analogue seems to be the antecedent of a conditional. Suppose p; is q true? This is just: is it true that p->q? So a way to show that you needed indices as well as contexts here would be to find two sentences p and q that did not differ in their truth-at-a-context profile: whenever p is true at a context, q is true at that context, and vice-versa. Yet we could try to find a sentence r that followed from the former but not the latter. That would show that p was contributing more to the evaluation of the conditional than just a set of contexts where it is true.
Suppose p; is r true? (yes)
Suppose q; is r true? (no)
For this strategy, we could use p = "I exist", and q = "I am here."
If I am here, then I am not there. (True)
If I exist, then I am not there. (False)
My method was another common one: just take p to be "I am not here." Since this is true in no context, every conditional with p as an antecedent should sound the same: either all trivially true or all uninterpretable (or whatever, given our theory of conditionals). The point is that there shouldn't be possible to find an A and a B such that "if p, A" strikes us as true while "if p, B" strikes us as false.
Let's try to see exactly how Lewis makes the point. Is it just a bald appeal to intuition? He considers sentences like
"If someone is speaking here then I exist." (True)
"Forevermore, if someone is speaking here then I will exist." (False)
NB The argument works as an appeal to intuition, but only because we are actually assuming that "If someone is speaking here then I exist" is true, and this is only because we haven't taken the more restricted view of indexicals. Clearly, "If someone is speaking in the Dennes Room then Melissa exists" is not true; my existence does not depend on whether people continue to talk in the Dennes Room. However, other cases could be constructed, as above.
****
It has just occurred to me that this might in fact be possible, and the way of explaining e.g. Escher staircase experiences of the type that interest Susanna Siegel...
Siegel, Susanna (2004). Indiscriminability and the Phenomenal. Phil. Studies.
Wednesday, September 8, 2010
Fregean contents again
Frege has been much in the air this week. Let's make sure we really understand what it's all about. What we have to puzzle out is (i) what it would mean for perceptual states to have "Fregean" (as opposed to/in addition to "Russellian") contents,
(ii) what kind of challenge indexicality, as we find it in natural language, poses for Frege (we do this in the absence of acquaintance with Frege's own work on the subject), (iii) what Frege can tell us about the distinction, recently discussed in Crimmins's "Hesperus and Phosphorus: Sense, Pretense, and Reference" between a sentence's truth-conditions and its modal contents.
I. Fregean and Russellian contents
Fregeans make a sense-reference distinction. Each meaningful term has two sorts of semantic values, a sense and a reference. The referent of a sentence is a truth-value. Senses determine reference; senses of whole sentences, therefore, are truth-conditions. One and the same referent, for a single term or for a whole sentence, may have different senses. Frege had two goals in doing this. One was to explain why identity statements could be contingently true. Another was to explain why they could be cognitively significant; different modes of presentation can plan distinct inferential roles in our mental lives.
At a first pass, to hold that a perceptual state exhibits Fregean contents is to hold that it it contains objects under modes of presentation. We could want these modes of presentation to explain (a) why it is that we do not always recognize the sameness of objects we encounter on different occasions (thus leaving space for cognitively significant breakthroughs when we do come to make informative identity statements on the basis of our perceptions). (b) a point more intimately related to phenomenology of perception, which we would have even if we were omniscient, and always knew when we were looking at the same thing twice. This is simply that when we see things, we see them in a certain phenomenal way. Perhaps that things we see are presented to us in a certain way is just completely obvious. The way in which things are presented to us is, for example, what naturalistic painters are good at capturing.
Siegel writes that
"one of the two roles of m.o.p.'s is to determine reference...another is to reflect cognitive significance."
What about the determination of reference? The intuition is that when we are perceptually in contact with particular objects, we can perceive them incorrectly yet still have contents involving them. So it seems that mode of presentation does not determine reference; reference is determined by context and causal contact. Note that whether or not this makes perceptual content different from linguistic content depends on whether we take the objects represented in experience to be represented in a "name-like" (or demonstrative-like) way, or in a "complex description"-like way. So what to do?...do we abandon Fregean contents, or endorse Russellian contents as well, to capture get the objects we are in causal contact with into the contents of our experience? Moreover, if we go the double-content route (both Fregean and Russellian), do we do so for objects, for properties, or for both? A "double-double" content of a red cube (called 'o') would then contain: (1) o, (2) a mode of presentation of o, (3) o's redness, (4) a mode of presentation of o's redness.
A puzzle: suppose we incorrectly perceive object o as orange (due to funny lighting). It is certainly o which we are (mis)perceiving, but are we (i) misperceiving its redness (presumably, as orange-ness), or (ii) failing to perceive its redness at all? If we go for (ii) then the double-double-content looks overstuffed; we aren't really getting (3) at all. This seems like the right intuition for this case. The difference between this case and the regular inverted spectrum cases (which inspired Shoemaker, for example, to endorse doubled content for color properties) is that the subject is mistaken by her own criteria; if she were to perceive the cube in regular lighting, she would call it "red", not "orange." On the other hand, the lawlike ways in which funny lighting gives rise to misperceptions of color might convince someone that (3) really gets into the content of the perceptual state after all; if the cube weren't red, it wouldn't have been perceived *as orange* in the funny light.
The upshot seems to be this. Frege's original purpose in making the sense-reference distinction was to get a "meaning" (semantic value) for lexical constituents that was fine-grained enough to explain the informativeness of identity statements, while still making it the case that the fine-grained meaning determined course-grained meaning. Now we see arguments that fine-grained (cognitive) content cannot determine coarse-grained (extensional) content. We could just go for both; perhaps not much is lost (according to "two-dimensionalists" about perceptual content) if all that needs to be added to Frege's story is that fine-grained cognitive content *in combination with context* determines extensional content. This is the kind of "narrow content" view (once) endorsed by Fodor. In formal semantics, when it is the context (rather than index) that determines the extension of [phi], then [phi] is an indexical. [phi] is a word, and a constituent of a larger sentence.
Now, I do NOT know what it would mean to say that a constituent of the content of a perceptual experience is an indexical, where 'constituent' is used in the same way.
We will continue this discussion in II below.
II. Frege and Indexicality.
We break from perceptual experience altogether to consider Frege and Indexicality. Consider what a proto-Fregean, equipped only with the sense-reference distinction and the two goals it intends to achieve (cognitive significance and the determination of reference), would have to say about the indexical "I". First, he would face a puzzle about just what the reference of "I" is, since it can be used by different people to refer to different people.
Rather than a sameness of identity underlying [Venus] a proliferation of senses [morning star, evening star] this case gives us a proliferation of different identities underlying a sameness of sense!
The appropriate thing to do, it seems, is abandon the idea that sense determines reference, and argue instead that the sense of "I" only determines reference on an occasion of use. We will have to individuate "occasions of use" finely, however, to capture the fact that only I can secure reference to me using the "I"-mode of presentation. The crucial feature of an "occasion of use," here, is who the user is; you and I cannot occupy the same "occasion of use".
The cognitive significance point is preserved, since it explains why it is informative to learn (on some occasions) that I am the tallest person in the room, while at other times, it is not informative (or indeed even true.) What about a rigid designator statement like "I am Melissa"? We can account for what is cognitively significant about this by characterizing ignorance as ignorance of features of context (aka "occasions of use.")
The new knowledge can be glossed metalinguistically:
I am the the referent of "Melissa".
...in which case we can characterize it as an ignorance of features of the world after all. But I suspect that this gloss is a violation of what---now that I can take the phrase from another authority!---I would call "semantic phenomenology." It seems that when I learn that e.g. *I'm* the one making the mess, what I learn is a fact about the world, not a fact about my language. But a deeper understanding of what is at stake in making this point would be facilitated by a better understanding of the two kinds of disquotational and referential principles we use (as discussed for example by McG/McL).*
III. Crimmins's distinction between truth-conditions and modal contents
The simple move here appears to be equating truth-conditions with communicative content (what Dummett calls "Assertoric content") and modal contents with, well, modal contents (what Dummett calls "Ingredient sense"). We can think of what Crimmins says about compositionality in this light. It is ingredient sense--modal content--which is directly constrained by compositionality, because it is in this mode that we consider what a well-formed sentence needs to contribute to larger sentences of which it is a constituent.
We do not assert the sub-sentences of our asserted sentences (except perhaps in the very special case of sentences conjoined by "and") so there is no need to assign assertoric contents directly to sub-sentences. Thus we have some wiggle room to characterize the communicative (= assertoric) content differently than we characterize the modal content of the same sentence...and perhaps we need to do so by explaining mechanisms of pretense, irony, metaphor, etc.
The distinction is particularly important for a pretense account because it is truth-conditions and not modal contents which are globally affected by pretense. It is no part of the pretense account that there are e.g. pretense-referencing or pretense-triggering lexemes within identity statements (or nonexistence statements, etc.) themselves. Rather, there are classifications of whole chunks of discourse, well above the sentential level.
The account can be usefully compared with discourse representation theory in this way...*Except that*, in discourse representation theory, some lexemes *do* operate directly on a representation which is built up above the sentential level!
****
Siegel, S. "The contents of perception", Stanford Encyclopedia of Philosophy
Crimmins, M. "Hesperus and Phosphorus: Sense, Pretense, and Reference." In Martinich, ed., The Philosophy of Language (5th edition), Oxford.
(ii) what kind of challenge indexicality, as we find it in natural language, poses for Frege (we do this in the absence of acquaintance with Frege's own work on the subject), (iii) what Frege can tell us about the distinction, recently discussed in Crimmins's "Hesperus and Phosphorus: Sense, Pretense, and Reference" between a sentence's truth-conditions and its modal contents.
I. Fregean and Russellian contents
Fregeans make a sense-reference distinction. Each meaningful term has two sorts of semantic values, a sense and a reference. The referent of a sentence is a truth-value. Senses determine reference; senses of whole sentences, therefore, are truth-conditions. One and the same referent, for a single term or for a whole sentence, may have different senses. Frege had two goals in doing this. One was to explain why identity statements could be contingently true. Another was to explain why they could be cognitively significant; different modes of presentation can plan distinct inferential roles in our mental lives.
At a first pass, to hold that a perceptual state exhibits Fregean contents is to hold that it it contains objects under modes of presentation. We could want these modes of presentation to explain (a) why it is that we do not always recognize the sameness of objects we encounter on different occasions (thus leaving space for cognitively significant breakthroughs when we do come to make informative identity statements on the basis of our perceptions). (b) a point more intimately related to phenomenology of perception, which we would have even if we were omniscient, and always knew when we were looking at the same thing twice. This is simply that when we see things, we see them in a certain phenomenal way. Perhaps that things we see are presented to us in a certain way is just completely obvious. The way in which things are presented to us is, for example, what naturalistic painters are good at capturing.
Siegel writes that
"one of the two roles of m.o.p.'s is to determine reference...another is to reflect cognitive significance."
What about the determination of reference? The intuition is that when we are perceptually in contact with particular objects, we can perceive them incorrectly yet still have contents involving them. So it seems that mode of presentation does not determine reference; reference is determined by context and causal contact. Note that whether or not this makes perceptual content different from linguistic content depends on whether we take the objects represented in experience to be represented in a "name-like" (or demonstrative-like) way, or in a "complex description"-like way. So what to do?...do we abandon Fregean contents, or endorse Russellian contents as well, to capture get the objects we are in causal contact with into the contents of our experience? Moreover, if we go the double-content route (both Fregean and Russellian), do we do so for objects, for properties, or for both? A "double-double" content of a red cube (called 'o') would then contain: (1) o, (2) a mode of presentation of o, (3) o's redness, (4) a mode of presentation of o's redness.
A puzzle: suppose we incorrectly perceive object o as orange (due to funny lighting). It is certainly o which we are (mis)perceiving, but are we (i) misperceiving its redness (presumably, as orange-ness), or (ii) failing to perceive its redness at all? If we go for (ii) then the double-double-content looks overstuffed; we aren't really getting (3) at all. This seems like the right intuition for this case. The difference between this case and the regular inverted spectrum cases (which inspired Shoemaker, for example, to endorse doubled content for color properties) is that the subject is mistaken by her own criteria; if she were to perceive the cube in regular lighting, she would call it "red", not "orange." On the other hand, the lawlike ways in which funny lighting gives rise to misperceptions of color might convince someone that (3) really gets into the content of the perceptual state after all; if the cube weren't red, it wouldn't have been perceived *as orange* in the funny light.
The upshot seems to be this. Frege's original purpose in making the sense-reference distinction was to get a "meaning" (semantic value) for lexical constituents that was fine-grained enough to explain the informativeness of identity statements, while still making it the case that the fine-grained meaning determined course-grained meaning. Now we see arguments that fine-grained (cognitive) content cannot determine coarse-grained (extensional) content. We could just go for both; perhaps not much is lost (according to "two-dimensionalists" about perceptual content) if all that needs to be added to Frege's story is that fine-grained cognitive content *in combination with context* determines extensional content. This is the kind of "narrow content" view (once) endorsed by Fodor. In formal semantics, when it is the context (rather than index) that determines the extension of [phi], then [phi] is an indexical. [phi] is a word, and a constituent of a larger sentence.
Now, I do NOT know what it would mean to say that a constituent of the content of a perceptual experience is an indexical, where 'constituent' is used in the same way.
We will continue this discussion in II below.
II. Frege and Indexicality.
We break from perceptual experience altogether to consider Frege and Indexicality. Consider what a proto-Fregean, equipped only with the sense-reference distinction and the two goals it intends to achieve (cognitive significance and the determination of reference), would have to say about the indexical "I". First, he would face a puzzle about just what the reference of "I" is, since it can be used by different people to refer to different people.
Rather than a sameness of identity underlying [Venus] a proliferation of senses [morning star, evening star] this case gives us a proliferation of different identities underlying a sameness of sense!
The appropriate thing to do, it seems, is abandon the idea that sense determines reference, and argue instead that the sense of "I" only determines reference on an occasion of use. We will have to individuate "occasions of use" finely, however, to capture the fact that only I can secure reference to me using the "I"-mode of presentation. The crucial feature of an "occasion of use," here, is who the user is; you and I cannot occupy the same "occasion of use".
The cognitive significance point is preserved, since it explains why it is informative to learn (on some occasions) that I am the tallest person in the room, while at other times, it is not informative (or indeed even true.) What about a rigid designator statement like "I am Melissa"? We can account for what is cognitively significant about this by characterizing ignorance as ignorance of features of context (aka "occasions of use.")
The new knowledge can be glossed metalinguistically:
I am the the referent of "Melissa".
...in which case we can characterize it as an ignorance of features of the world after all. But I suspect that this gloss is a violation of what---now that I can take the phrase from another authority!---I would call "semantic phenomenology." It seems that when I learn that e.g. *I'm* the one making the mess, what I learn is a fact about the world, not a fact about my language. But a deeper understanding of what is at stake in making this point would be facilitated by a better understanding of the two kinds of disquotational and referential principles we use (as discussed for example by McG/McL).*
III. Crimmins's distinction between truth-conditions and modal contents
The simple move here appears to be equating truth-conditions with communicative content (what Dummett calls "Assertoric content") and modal contents with, well, modal contents (what Dummett calls "Ingredient sense"). We can think of what Crimmins says about compositionality in this light. It is ingredient sense--modal content--which is directly constrained by compositionality, because it is in this mode that we consider what a well-formed sentence needs to contribute to larger sentences of which it is a constituent.
We do not assert the sub-sentences of our asserted sentences (except perhaps in the very special case of sentences conjoined by "and") so there is no need to assign assertoric contents directly to sub-sentences. Thus we have some wiggle room to characterize the communicative (= assertoric) content differently than we characterize the modal content of the same sentence...and perhaps we need to do so by explaining mechanisms of pretense, irony, metaphor, etc.
The distinction is particularly important for a pretense account because it is truth-conditions and not modal contents which are globally affected by pretense. It is no part of the pretense account that there are e.g. pretense-referencing or pretense-triggering lexemes within identity statements (or nonexistence statements, etc.) themselves. Rather, there are classifications of whole chunks of discourse, well above the sentential level.
The account can be usefully compared with discourse representation theory in this way...*Except that*, in discourse representation theory, some lexemes *do* operate directly on a representation which is built up above the sentential level!
****
Siegel, S. "The contents of perception", Stanford Encyclopedia of Philosophy
Crimmins, M. "Hesperus and Phosphorus: Sense, Pretense, and Reference." In Martinich, ed., The Philosophy of Language (5th edition), Oxford.
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