David Kaplan (philosopher)
David Kaplan | |
---|---|
Born | September 17, 1933 |
Nationality | American |
Education | demonstratives, "quantifying in", Kaplan's intensional paradox[2] |
Website | Faculty webpage |
David Benjamin Kaplan (
Education and career
Kaplan began as an undergraduate at
In most years, Kaplan teaches an upper division course on
In 2022 he received the Rolf Schock Prize in the category of "Philosophy".[8]
Philosophical work
This article possibly contains original research. (July 2017) |
Kaplan's work is primarily focused on issues in the philosophy of language and logic. These ventures, however, sometimes take him into related issues in other fields, such as the philosophy of mind.
Semantics for indexicals and demonstratives
Kaplan's most influential contribution to the philosophy of language is his
Kaplan's insights center on two key distinctions, which may be seen as responses to the inability of Frege's semantics to deal with context-sensitivity in language. First, in place of Frege's categories of Sinn and Bedeutung (typically translated as "sense" and "reference"), Kaplan introduces the notions of character and content. The former is the
From these rough distinctions, Kaplan then defines character and content more precisely. Character defines a function associated by convention with an expression, which takes contextual elements as arguments and yields content as values. Content, on the other hand, defines a function taking as arguments those elements of the circumstances of evaluation relevant to determining extension, and yielding the
Two more important notions can thus be defined. We can say that an expression is context-sensitive if and only if its character defines a non-constant function (i.e., if, and only if it yields different content-values given different context-element-arguments). An expression is context-insensitive if and only if its character defines a constant function. Also, the distinction between character and content breaks down in the case of context-insensitive expressions, and convention associates each such expression directly with a content.
On the other hand, an expression is directly referential if, and only if its content defines a constant function from circumstances of evaluation to extension. Kaplan also characterizes directly referential expressions as those that refer without the mediation of a Fregean Sinn, or as those whose only contribution to content are their referents. Thus, in the case of directly referential expressions, we can say that the distinction between content and referent breaks down.
Any singular term is directly referential according to Kaplan. So the following intuitive picture emerges: the meaning of an indexical is a rule taking us from some part of the context to an expression, and the meaning of an expression is a bit of propositional content that determines the extension in each possible world.
Kaplan goes on to use this semantic scheme to explain phenomena concerning the relationship between necessary and a priori truth. An utterance is said to be necessarily true if, and only if the content it expresses is true in every possible circumstance; while an utterance is said to be true a priori if, and only if it expresses, in each context, a content that is true in the circumstances that context is part of. So, "I am here now" is true a priori because each of the indexical expressions used ('I', 'here', 'now') directly refer to the speaker, location, and time of utterance. But the utterance is not necessarily true, because any given speaker might have been in at a different place at that time, given different circumstances of evaluation. On the other hand, "I am David Kaplan," as spoken by David Kaplan, is necessarily true, since "I" and "David Kaplan" (both directly referential expressions) refer to the same object in every circumstance of evaluation. The same statement is not true a priori, however, because if it were spoken in a different context (e.g., one with a speaker other than Kaplan), it might be false.
Another result of Kaplan's theory is that it solves
Kaplan's semantic theory faces a problem, however, with proper names, which seem both directly referential and context-insensitive. On Kaplan's account, this means that constant functions are defined by both a proper name's character and its content, which would imply that proper names have no meaning other than their reference. While this approach to proper names is not novel (
Quantifying in
In his article "Quantifying In" (1968), Kaplan discusses issues in intensional and indirect (Ungerade, or oblique) discourse, such as substitution failure, existential generalization failure, and the distinction between de re / de dicto propositional attitude attributions. Such issues were made salient primarily by W. V. Quine in his "Quantifiers and Propositional Attitudes" (1956).
The phrase "quantifying in" comes from Quine's discussion of what he calls "relational" constructions of an existential statement. In such cases, a variable bound by an anterior variable-binding operator occurs within a non-extensional context such as that created by a 'that' clause, or, alternatively, by propositional attitude or modal operators. The "quantifying in" idiom captures the notion that the variable-binding operator (for example, the existential quantifier 'something') reaches into, so to speak, the non-extensional context to bind the variable occurring within its scope. For example, (using a propositional attitude clause), if one quantifies into the statement "Ralph believes that Ortcutt is a spy," the result is (partly formalized):
- (Ǝx) (Ralph believes that x is a spy)
- ["There is someone Ralph believes is a spy"]
In short, Kaplan attempts (among other things) to provide an apparatus (in a Fregean vein) that allows one to quantify into such intensional contexts even if they exhibit the kind of substitution failure that Quine discusses. If successful, this shows that Quine is wrong in thinking that substitution failure implies existential generalization failure for (or inability to quantify into) the clauses that exhibit such substitution failure.
Logic 2000 program
In recent years, Kaplan has devoted much effort to teaching introductory logic. A main contribution has been his work to create a computer program, Logic 2000, on which students can do their assignments. Logic 2000 is currently available for use free of charge. The program has many parts, including a derivations module, a symbolizations module, a models module, and much more. The program was initially developed to complement the logic text of Donald Kalish and Richard Montague, and the derivations module therefore uses their distinctive natural deduction system. Perhaps the most significant features of the program are its feedback and error-checking capacities. The program can provide a student with immediate and extensive error messages detailing any errors the student may have made on the problem he or she is currently working on. The program's current iteration and name is Logic 2010.[9]
Bibliography
- "Quantifying In," Synthese, XIX 1968.
- "On the Logic of Demonstratives," Journal of Philosophical Logic, VIII 1978: 81–98; and reprinted in French et al. (eds.), Contemporary Perspectives in the Philosophy of Language (Minneapolis: University of Minnesota Press, 1979): 401–412.
- "Dthat," Syntax and Semantics, vol. 9, ed. P. Cole (New York: Academic Press, 1978); and reprinted in The Philosophy of Language, ed. A. P. Martinich (Oxford: Oxford University Press, 1985).
- "Bob and Carol and Ted and Alice," in Approaches to Natural Language (J.Hintikka et al., eds.), Reidel, 1973.
- "How to Russell a Frege-Church," The Journal of Philosophy, LXXII 1975.
- "Opacity," in W. V. Quine(L. Hahn, ed.), Open Court, 1986.
- "Demonstratives" and "Afterthoughts" in Themes from Kaplan (Almog, et al., eds.), Oxford 1989. ISBN 978-0-19-505217-6
- "Words," The Aristotelian Society, Supplementary Volume, LXIV 1990
- "A Problem in Possible World Semantics," in Modality, Morality, and Belief (W. Sinnott-Armstrong et al., eds.) Cambridge, 1995.
- "Reading 'On Denoting' on its Centenary", Mind, 114 2005: 934–1003.
See also
References
- ^ Two-Dimensional Semantics (Stanford Encyclopedia of Philosophy)
- ^ Andrew Bacon, John Hawthorne & Gabriel Uzquiano, "Higher-order free logic and the Prior-Kaplan paradox", Canadian Journal of Philosophy 46(4–5): 493–541 (2016).
- ^ "David Kaplan - Faculty".
- ^ "American Academy of Arts and Sciences | UCLA".
- ^ "David Kaplan - British Academy". Archived from the original on 2015-07-07. Retrieved 2015-07-06.
- ^ a b The Philosophy of David Kaplan. Oxford University Press. 2008. pp. 27–8.
- ^ "CFUL – Centre of Philosophy University of Lisbon". Archived from the original on 2017-08-13. Retrieved 2017-08-13.
- ^ "Rolf Schock Prize 2022". Archived from the original on 2022-03-25. Retrieved 2022-03-24.
- ^ The program may be obtained at [1].
Further reading
- Joseph Almog & Paolo Leonardi, eds., The Philosophy of David Kaplan, Oxford University press, 2009. ISBN 978-0-195-36788-1
External links
- Braun, David. "Indexicals". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.