Grad Seminar on Twin Earth and its Epistemological Consequences

Phil 523. Grad Seminar on Twin Earth

Tuesdays 7-10 PM, Marx Hall 201

Spring 2003

Jim Pryor

This seminar explores some issues in epistemology and philosophy of mind raised by Twin Earth thought-experiments. We'll be talking about these topics:

Externalism about content
The nature of a priori knowledge
The nature and epistemology of de re belief
Connections between indexicality and a prioricity
The relations between externalism and knowledge of the contents of your own thoughts
Reference-fixing and whether it gives us a priori knowledge
How to understand the necessary a posteriori and illusions of contingency
Two-dimensionalist theories of content, and the kinds of a priori knowledge they assume we can have

Topics and Readings

A "*" indicates that a copy of the reading is already on reserve in the Philosophy library. I'll put copies of the rest on reserve later, and will put readings on electronic reserve, as well.

I've cited reprints where I know about them, to help you get ahold of the articles more easily.

For most weeks, I've listed only a few central readings. I'll be assigning and recommending more as the term proceeds.

Week 1 (2/4). Introduction

Quick overview of Putnam and Kripke
"Narrow Content"
The Necessary a posteriori and illusions of contingency.
Two-dimensionalist theories of content

Optional Background Reading

* Brian Loar, "Social Content and Psychological Content," in R.H. Grimm and D.D. Merrill, eds. Contents of Thought (Univ. of Arizona Press, Tucson, 1988). Reprinted in David M. Rosenthal, ed., The Nature of Mind (Oxford Univ. Press, Oxford, 1991); and in Andrew Pessin and Sanford C. Goldberg, eds., The Twin Earth Chronicles (Paragon House, New York, 1995).

* Robert Stalnaker, "Narrow Content," in C. Anthony Anderson and Joseph Owens, eds. Propositional Attitudes: the role of content in logic, language, and mind (CSLI, Stanford, 1990). Reprinted in Robert Stalnaker, Context and Content: Essays on Intentionality in Speech and Thought (Oxford Univ. Press, Oxford, 1999).

* Ernest LePore and Barry Loewer, "Solipsistic semantics," in P.A. French, T.E. Uehling and Howard Wettstein, eds. Midwest Studies in Philosophy 10 (1986).

Chalmers, "The Foundations of Two-Dimensionalist Semantics," <http://www.u.arizona.edu/~chalmers/papers/foundations.html>.

Week 2 (2/11). Studying Twin Earth More Closely

How do the Twin Earth thought-experiments work?
What assumptions do they make?
What exactly are they supposed to establish?

Readings

* Hilary Putnam, "Meaning and reference," Journal of Philosophy 70 (1973), 699-711. Reprinted in Stephen Schwartz, ed., Naming, Necessity and Natural Kinds (Cornell Univ. Press, Ithaca, 1977).

* Tyler Burge, "Other bodies," in Andrew Woodfield, ed. Thought and Object (Oxford Univ. Press, New York, 1982), 97-120. Reprinted in Andrew Pessin and Sanford C. Goldberg, eds., The Twin Earth Chronicles (Paragon House, New York, 1995).

Week 3 (2/18). A Priori Justification

Distinguishing a prioricity from other epistemological notions with which it's often confused
A priori justification can be defeasible
Why semantic beliefs, like "Tables" refers to tables, aren't a priori
Various sources of the contingent a priori

Readings

Laurence BonJour, "A rationalist manifesto," in Philip Hanson and Bruce Hunter, eds. Canadian Journal of Philosophy Suppl. Vol. 18 (1992). Reprinted in Albert Casullo, ed., A Priori Knowledge (Ashgate/Dartmouth, Aldershot, 1999).

Philip Kitcher, "A priori knowledge," Philosophical Review 89 (1980), 3-23. Reprinted in Albert Casullo, ed., A Priori Knowledge (Ashgate/Dartmouth, Aldershot, 1999); and in Sven Bernecker and Fred Dretske, eds., Knowledge: Readings in Contemporary Epistemology (Oxford Univ. Press, Oxford, 2000).

Albert Casullo, "Revisability, reliabilism and a priori knowledge," Philosophy and Phenomenological Research 49 (1988). Reprinted in Albert Casullo, ed., A Priori Knowledge (Ashgate/Dartmouth, Aldershot, 1999).

Weeks 4-5 (2/25-3/4). De Re Beliefs and Indexicals

What we mean by calling a belief "de re," and what kind of content we should think of de re beliefs as having
We should understand most indexical beliefs to be de re
Indexical beliefs like I am here now are not a priori
When should we say that two subjects have "the same" de re or indexical belief?
To what extent are beliefs about natural kinds analogous to de re beliefs?
Twin Earth considerations don't support regarding names and natural kind terms as indexical

Some Readings (there will be more)

Some papers that argue for reducing de re beliefs to descriptive de se beliefs (e.g., Lewis, Chisholm)

John Perry, "The problem of the essential indexical," Nous 13 (1979). Reprinted in Nathan Salmon and Scott Soames, eds., Propositions and Attitudes (Oxford Univ. Press, Oxford, 1988); and in Quassim Cassam, ed., Self-Knowledge (Oxford Univ. Press, Oxford, 1994); and in John Perry, The Problem of the Essential Indexical and Other Essays, expanded ed. (Oxford Univ. Press, New York, 2000).

David Kaplan, "Demonstratives" and "Afterthoughts," in Joseph Almog, John Perry and Howard Wettstein, eds. Themes from Kaplan (Oxford Univ. Press, Oxford, 1989).

Scott Soames, Beyond Rigidity, Chapters 9-11

Joseph Almog, "Dthis and dthat: indexicality goes beyond that," Philosophical Studies 39 (1981).

Weeks 6-7 (3/11, Spring Break, 3/25). Externalism and Self-Knowledge

The "McKinsey argument" seems to show that we couldn't know, just by reflection, what the wide contents of our thoughts are.

Another argument concerns "slow switching" cases, where a subject who grew up on Earth is surreptitiously transplanted to Twin Earth. Many find it plausible that the difference in the subject's environment would gradually make a difference to the wide content of her thoughts; but this difference would not be accessible to the subject on the basis of reflection alone. On the basis of reflection alone, she would not be able to tell that she wasn't still on Earth.

These two arguments seem to provide a good case for narrow content. If our thoughts had narrow contents, then even if McKinsey's argument succeeded, we could still know about them by reflection alone. In addition, the narrow contents of our thoughts would be preserved even if unnoticed changes in our environment gradually changed the wide contents. So the sameness of narrow content could be used to explain why everything still "seems the same" to us.

However, I'll argue that we don't need narrow content to solve these puzzles.

Readings

Jessica Brown, "The incompatibility of anti-individualism and privileged access," Analysis 55 (1995). Reprinted in Peter Ludlow and Norah Martin, eds., Externalism and Self-Knowledge (CSLI Publications, Stanford, 1998).

Paul Boghossian, "Content and self-knowledge," Philosophical Topics 17 (1989). Reprinted in Peter Ludlow and Norah Martin, eds., Externalism and Self-Knowledge (CSLI Publications, Stanford, 1998); and in Sven Bernecker and Fred Dretske, eds., Knowledge: Readings in Contemporary Epistemology (Oxford Univ. Press, Oxford, 2000).

Paul Boghossian, "What the externalist can know a priori," Proceedings of the Aristotelian Society 97 (1997). Reprinted in Crispin Wright, Michael Smith and Cynthia Macdonald, eds., Knowing Our Own Minds: Essays in Self-Knowledge (Oxford Univ. Press, Oxford, 1998); and in Philosophical Issues 9 (1998).

Bill Brewer, "Externalism and a priori knowledge of empirical facts," in Paul Boghossian and Christopher Peacocke, eds. New Essays on the A Priori (Oxford Univ. Press, Oxford, 2000).

Brian McLaughlin and Michael Tye, "Is content-externalism compatible with privileged access?," Philosophical Review 107 (1998).

Pryor, "Externalism about Content and McKinsey-style Reasoning," <http://www.princeton.edu/~jimpryor/papers/McKinsey.pdf>.

Weeks 8-9 (4/1-4/8). Will we have enough descriptive knowledge to fix the reference of our terms?

Two-dimensionalists assume we're in a position to have robust bodies of a priori knowledge about the referents of our words. For instance, they'll say we can know a priori that the stuff "water" refers to is the clear drinkable liquid predominant in the lakes and rivers around here. This knowledge is supposed to be common property among everyone who has thoughts with the same narrow content as our water thoughts, even if the wide contents of these thoughts in some cases concern H₂O, in other cases XYZ, and in other cases even more exotic substances.

Let's grant we do associate some descriptive stereotype with "water." Will this stereotype be informative enough to uniquely identify water? Will we give it reference-fixing authority, or will we regard it as defeasible?

Readings

Frank Jackson, "Reference and description revisited," in James Tomberlin, ed. Philosophical Perspectives 12 (1998).

Byrne and Pryor, "Bad intensions," <http://web.mit.edu/abyrne/www/BadIntensions.pdf>.

Weeks 10-11-12 (4/15-4/22-4/29). What is the epistemic status of that descriptive knowledge, when we do have it?

Kind terms are either (i) synonymous with descriptions of the form "the actual so-and-so around here," or (ii) de re.

If (i), we could have a priori identifying knowledge about the relevant kinds. But it's implausible for independent reasons that all (or even many) kind terms are of type (i).

If (ii), there's no reason to think we'll be in a position to have the a priori identifying knowledge. Many philosophers think that if you fix the reference of a name like "Julius" to be the inventor of the zipper, then it will be knowable a priori--at least for you--that Julius invented the zipper. But I will argue that this view is mistaken.

Hence, for some (many) kind terms, we won't have a priori identifying knowledge.

Readings

Soames, The Age of Meaning, Chapter 14

Jason Stanley, "Names and rigid designation," in Bob Hale and Crispin Wright, eds. A Companion to the Philosophy of Language (Blackwell, Oxford, 1997).

Soames, Beyond Rigidity, Chapters 2 and 5

Soames, The Age of Meaning, Chapter 16

Keith Donnellan, "The contingent a priori and rigid designators," in P.A. French, T.E. Uehling and Howard Wettstein, eds. Midwest Studies in Philosophy 2 (1977).

Gareth Evans, "Reference and contingency," Monist 62 (1979). Reprinted in Gareth Evans, Collected Papers (Oxford Univ. Press, Oxford, 1985).

Some of Robin Jeshion's stuff.