Kaplan on demonstratives 10/3

Transcription

1 Kaplan on demonstratives 10/3 Philosophy of Language, Fall 2015 Peter van Elswyk, Rutgers University 1 The key ideas 1.1 Indexicals Indexicals are words whose meaning depends on context. Kaplan distinguishes between pure indexicals (e.g. I, here, now) and true demonstratives (e.g. that, this). What distinguishes the two is how context determines their meaning. Pure indexicals have their meaning determined automatically. Nothing further is required by the speaker. Not so for true demonstratives. They require something extra. We will return to this issue at the end of class. 1.2 Two principles Kaplan starts off with two principles. Individually, each principle is highly plausible. Together, they appear to be in tension. principle one: The referent of an indexical depends on context. principle two: Indexicals are directly referential. principle one states that indexicals vary their referents with something. In contrast, principle two states that indexicals do not vary their referents with something. To fully appreciate the latter principle, remember that directly referential expressions are rigid designators. They refer to the same individual without deviation across times or possible worlds.

2 kaplan on demonstratives 2 Kaplan s resolution to this tension is to add a new dimension to meaning. The referent of an indexical depends on context, but, once context determines the referent, the indexical is directly referential. It does not vary for across circumstances of evaluation. Once more, but slower. In distinguishing names from descriptions, Kripke reminded us to be sensitive to the worlds and times at which we evaluate descriptions. For example, The President of Rutgers will pick out different individuals at different worlds and at different times. Kaplan identifies the circumstance of evaluation with pairs of worlds and times. So we already have one dimension of meaning. Kaplan s innovation following Kamp s (1971) analysis of now is to add a second dimension. In addition to the circumstance of evaluation, we have to assess expressions at the context of utterance. This happens first. Once the context c determines an indexical s referent, the indexical is directly referential and does not vary what it refers to across circumstances of evaluation. 1.3 Character Kaplan s picture is sometimes called two dimensionalism. That s because he says that expressions have a meaning that gets assessed at the context and a meaning that gets assessed at the circumstance. character content context speaker, addressee location, time... truth value True, False circumstance worlds, times... The first dimension of meaning he calls character. Character is a function from contexts to content: supply a context, and character will supply the content. Some expressions then have variable or constant character. If they have the former, they denote different things in different contexts. If they have the latter kind of character, the denote the same thing regardless of the context in which they are used. The second dimension of meaning is content. Content is a function from a circumstance to a truth value: supply a circumstance, and content will supply a truth value.

3 kaplan on demonstratives 3 (Here s a technical way to represent what s going on. Let be an interpretation function that takes natural language expressions to their denotations. To illustrate, assume a Millian view of names. Then Ari = Ari. What we learned from Kripke was that the denotation of a definite description can be sensitive to the times and possible worlds at which it is evaluated. That requires us to add a parameter to the interpretation function. Where w represents the world of evaluation and t represents the time of evaluation, the function now looks like this: w,t. These additions are the circumstances of evaluation. The interpretation function then becomes a function from worlds and times to denotations. Kaplan s contribution was that these parameters are not enough. In addition, we need to add a completely different parameter for context. So the interpretation function must look like c, w,t and become a function from context and the circumstances of evaluation (e.g. worlds, times) to denotations.) What other features do you think should be in the context or in the circumstance of evaluation? Give examples with respect to particular expressions. 2 Intermission: Kripke and Frege Kaplan follows Kripke in his commitment to direct reference. Kripke thinks that names are rigid designators while Kaplan thinks indexicals are rigid designators. But more than that, Kaplan offers a fuller picture for how expressions end up rigid by introducing the notion of character and this constitutes a departure from Kripke. Kaplan (1989: ) puts matters as follows: For me, the intuitive idea is not that of an expression which turns out to designate the same object in all possible circumstances, but an expression whose semantical rules provide directly that the referent in all possible circumstances is fixed to be the actual referent. In typical cases the semantical rules will do this only implicitly, by providing a way of determining the actual referent and no way of determining any other propositional component. We should beware of a certain confusion in interpreting the phrase designates the same object in all circumstances. We do not mean that the expression could not have been used to designate a different object. We mean rather that given a use of the expression, we may ask of what has been said whether it would have been true or false in various counterfactual circumstances, and in such counterfactual circumstances, which are the individuals relevant to determining truth-value. Thus we must distinguish possible occasions of use which I call contexts from possible circumstances of evaluation of what was said on a given occasion of use. By following Kripke down the path of direct reference, Kaplan is at odds with Frege who thought senses mediated all reference in language. But the introduction of character gives Kaplan something that is sense like. Kaplan (1989: 524) puts it this way: The relationship of character to content is something like

4 kaplan on demonstratives 4 that traditionally regarded as the relationship of sense to denotation, character is a way of presenting content. For example, we can think of the character of now as providing a rule to find a referent in the context of utterance. The rule it provides is this: find the current time. Similar rules can be provided for other indexicals. As a result, Kaplan thinks he has a solution to Frege s puzzle over how a=a and a=b can differ in cognitive significance. The explanatory difference is that a and b have different characters. They might refer to the same entity and have the same referent, but the semantic rule associated with each is different. For example, him and that guy might refer to the same individual in a context of use, but each expression has a different semantic rule for how a referent is retrieved. Is character enough to solve Frege s puzzles? And does it provide a solution to both puzzles? 3 Quarantine 3.1 I am here now A crucial feature of Kaplan s semantics is that the context and circumstance of evaluation are kept separate from one another. They are quarantined off. Here is a Kaplan style arguments for containment. Suppose that the context included in the circumstance of evaluation. content circumstance worlds, times context truth value True, False This is a one dimensional picture of meaning. Once we have a our content, we just have to check it against a circumstance of evaluation and a truth value will be supplied. Now consider an expression like this: (1) I am here now.

5 kaplan on demonstratives 5 (1) is loaded with indexicals. A one dimensional picture of meaning allows us to vary all of parts of a circumstance of evaluation. But now we can pick combinations of worlds, times, and speakers so that (1) comes out false. This is the wrong prediction. There is something about (1) that makes it true for any arbitrary context that we could choose. Two dimensionalism delivers this verdict by keeping the circumstance of evaluation distinct from the context of utterance. There is the context, which supplies indexicals with their referents, and there is the circumstance of evaluation which is where sentences get assessed. Can you see any way for the one dimensionalist to avoid making a bad prediction? 3.2 Operators and monsters A guiding idea for Kaplan is that only the circumstance of evaluation can be shifted by operators. Operators come in a number of forms. We will consider modal operators like possibly or necessarily and temporal operators like yesterday or tomorrow. What these operators do is shift the circumstance of evaluation. (2) Possibly, Pauly D went to the gym. (3) Previously, Snookie went to the shore. In (2), the circumstance is shifted by possibly to a possible world that is potentially not the actual world. In other words, (2) is true just in case there exists a world where Pauly D went to the gym. In (3), the world part of the circumstance is left unshifted by the operator previously, but the time of the circumstance is pushed back in time. (3) is true just in case at a prior time in our world Snookie went to the shore. (Logically, we can treat operators as adjusting the world and time parameters on the interpretation function c, w,t in the metalanguage. So Possibly, φ c, w,t = True iff there exists a world w such that φ c, w,t = True. Similarly, Previously, φ c, w,t = True iff there exists a time t such that t <t and φ c, w,t = True.) Kaplan was committed to this idea because of his commitment to quarantine. He needed indexicals to be unaffected by the above operators. For example, the indexicals in (4) and (5) should not be influenced by the operators. (4) Possibly, I went to the gym. (5) Yesterday, he went to the shore.

6 kaplan on demonstratives 6 Possibly and yesterday should not influence the meaning of I or he. Kaplan s semantics provides this by having the two dimensions quarantined off. But Kaplan has another reason for this idea. He thinks indexicals are directly referential (e.g. principle two). Nothing like Fregean sinn mediates their reference. If indexicals could be operated on, it would suggest that they are not direct. They depend on some intermediary feature of their meaning that can be shifted by the right operators. As a result, Kaplan s commitment to direct reference makes him think that only the circumstance of evaluation can be shifted by operators. Nothing can operate on indexicals because they immediately find their referents once they are used in a context. Put differently, Kaplan s two dimensional picture of meaning places character prior to content. Then Kaplan insists that all operators in language operate on content to shift the circumstance of evaluation. There are zero operators on character, which he calls monsters. (Were there monstrous operators in natural language, there would be an operator such that φ c, w,t = True iff, in context c, φ c, w c,t c = True.) Whether or not monsters exist in natural language has been hotly contested in recent years by philosophers and linguists alike. Some have claimed that there are monsters in English. Here s Schlenker (2003: 98): Monsters do exist in natural language. Each time we report somebody s speech or thought we use one. Other languages appear to have them for pure indexicals like I (e.g. Amharic, Navajo, Zazaki, Slave). Can you think of any monstrous operators in English? (hint: Read the Schlenker quote again.) 4 Metasemantics again 4.1 Disambiguation Recall the distinction we drew last week between two types of questions we can ask about meaning. semantic question. What is the meaning of expression e? metasemantic question. How is expression e s meaning determined? This distinction needed to be drawn to properly understand Kripke s causal historical theory of reference. His theory was not a semantic theory, but a metasemantic theory. Equipped with Kaplan s notion of character, we can now disambiguate two versions of the metsemantic question.

7 kaplan on demonstratives 7 metasemantic (1). How is expression e s character determined? metasemantic (2). How is the input to expression e s character determined in a context? The first disambiguation is (more or less) equivalent to metasemantic question. But the second disambiguation asks a very different question that applies only to context sensitive expressions. 4.2 Metasemantics of context sensitivity metasemantic (2) is a question about how context helps to determine the meaning of a context sensitive expression. Pure indexicals have simple, automatic rules. True demonstratives do not. As we said at the outset, they require something extra. Kaplan s (1989: ) initial answer was that demonstratives require extralinguistic demonstrations like gestures: A demonstrative without an associated demonstration is incomplete. The linguistic rules which govern the use of the true demonstratives that, he, etc., are not sufficient to determine their referent in all contexts of use. Something else an associated demonstration-must be provided. The linguistic rules assume that such a demonstration accompanies each (demonstrative) use of a demonstrative. An incomplete demonstrative is not vacuous like an improper definite description. A demonstrative can be vacuous in various cases. For example, when its associated demonstration has no demonstratum (a hallucination) or the wrong kind of demonstratum (pointing to a flower and saying be in the belief that one is pointing to a man disguised as a flower) or too many demonstrata (pointing to two intertwined vines and saying that vine ). But it is clear that one can distinguish a demonstrative with a vacuous demonstration: no referent; from a demonstrative with no associated demonstration: incomplete. Without an extra demonstration, demonstratives are incomplete. They do not just fail to refer, they just fail to have meaning altogether. It is still unresolved in the philosophy of language how to best answer metasemantic (2). Part of what makes it puzzling is that there is diverse variety of context sensitive expressions. In addition to demonstratives and indexicals, there are gradable adjectives (tall, long), modals (might, must), attitude verbs (knows), and many more. Glanzberg (2007: 17) puts this point as follows: Metasemantics, especially the metasemantics of contextual parameters, is a notoriously messy subject, about which we understand relatively little. This is no failure of any given semantic analysis. For instance, though it falls on the simple side of metasemantics, it is already a very messy issue just how demonstrated objects are identified. However messy this may be, it is no reason to reject the semantics which says a demonstrative picks out a demonstrated object. Difficulties in the metasemantics here do not make us doubt the semantics itself.

8 kaplan on demonstratives 8 It is easy to think of counterexamples to the requirement that there be demonstrations. Think of a counterexample and then think of a new requirement that explains your counterexample.