Responses to articles on my work
This page is mostly for brief responses to published or forthcoming
articles that discuss my work. I've starred [*] the more technical
entries so nonphilosophers can skip them. (The first
entry is probably the best place for nonphilosophers to start.)
These responses are "unofficial", but if you'd like to use
them in an article, feel free to ask. See also online
discussions of my work for some further papers and other
discussion (without responses).
Table of contents: A link on the author's name goes to an entry further down on this page.
- Journal of Consciousness Studies symposium on the "hard problem" (26 papers).
- Reviews of The Conscious Mind.
- Katalin Balog, Conceivability, possibility,
and the mind-body problem. Philosophical Review 108:497-528, 1999.
- Tim Bayne, Chalmers
on the justification of phenomenal judgment. Philosophy
and Phenomenological Research 62:407-19, 2000.
- George Bealer, Modal epistemology and the rationalist renaissance. In (T. Gendler and J. Hawthorne, eds) Conceivability and Possibility. Oxford
University Press, 2002.
- Mark Bishop, Counterfactuals cannot count: A rejoinder to David Chalmers. Consciousness and Cognition, 11:642-52, 2002.
- Mark Bishop, Dancing with pixies: Strong artificial intelligence and panpsychism. In (J. Preston and J.M. Bishop, eds) Views into the Chinese Room. Oxford University Press, 2002.
- Ned Block and Robert Stalnaker, Conceptual
analysis, dualism, and the explanatory gap. Philosophical
Review 108:1-46, 1999.
- Andrew Botterell, Conceiving what is not there. Journal of Consciousness
Studies 8:21-42, 2001.
- David Braddon-Mitchell, Qualia and analytic conditionals. Journal of Philosophy 100:111-35, 2003.
- Anthony Brueckner, Chalmers' conceivability argument for dualism. Analysis 61:187-93, 2001.
- Alex Byrne, Cosmic hermeneutics.
Philosophical Perspectives 13:347-83, 1999.
- Alex Byrne, Chalmers on epistemic content. SOFIA conference on Metaphysics of Mind, December 2001.
- Alex Byrne, Intentionalism defended.
Philosophical Review 110:199-240, 2002.
- Alex Byrne and Ned Hall, Chalmers on consciousness
and quantum mechanics. Philosophy of Science 66:370-90, 1999.
- Alex Byrne and Jim Pryor, Bad intensions. In (M. Garcia-Carpintero & J. Macia, eds) Two-Dimensional Semantics: Foundations and Applications (OUP, 2006).
- Patricia Churchland, The hornswoggle problem. Journal of Consciousness Studies 3: 402-8, 1996.
- Paul Churchland, The rediscovery of light.
Journal of Philosophy 93:211-28, 1996.
- Daniel Dennett, Facing backward on the problem of consciousness. Journal of Consciousness Studies 3: 4-6, 1996.
- Daniel Dennett, The fantasy of first-person
science. Northwestern University, February 2001.
- William Greenberg, On Chalmers' principle
of organizational invariance and his `dancing qualia' and `fading qualia'
thought experiments. Journal of Consciousness Studies 5:53-58, 1998.
- John Hawthorne, Advice to physicalists. Philosophical Studies 109:17-52, 2002.
- John Hawthorne, Direct reference and dancing qualia. In (T. Alter and S. Walter) Phenomenal Concepts and Phenomenal Knowledge (OUP, 2006).
- Christopher Hill, Chalmers
on the a priority of modal knowledge. Analysis 58:20-26, 1998.
- Christopher Hill and Brian McLaughlin, There are fewer things in reality than are dreamt of in Chalmers' philosophy. Philosophy and Phenomenological Research 59:445-54, 1999.
- Jenann Ismael, Science and the phenomenal.
Philosophy of Science 66:351-69, 1999.
- Mark Johnston, Manifest
kinds. Journal of Philosophy 94:564-83, 1997.
- Robert Kirk, Why there couldn't be zombies.
Aristotelian Society, Supplementary Volume 73:1-16, 1999.
- Noa Latham, Chalmers on the addition of consciousness
to the physical world. Philosophical Studies 98:71-97, 2000.
- Joseph Levine, Review of The Conscious Mind.
Mind 107:877-881, 1998.
- Joseph Levine, "Lately things don't seem the same": The conceivability argument. Chapter 2 of Purple Haze. Oxford University Press, 2001.
- Harry Lewis, Consciousness: Inexplicable
- and useless too? Journal of Consciousness Studies 5:59-66, 1998.
- Brian Loar, David Chalmers' The Conscious Mind. Philosophy and Phenomenological Research 59:465-71, 1999.
- Penelope Mackie, Deep contingency and necessary a posteriori truth. Analysis 62:225-36, 2002.
- Diego Marconi, Two-dimensional semantics and the articulation problem. Synthese 143:321-49, 2005.
- Andrew Melnyk, Physicalism unfalsified: Chalmers'
inconclusive conceivability argument. In (C. Gillett & B. Loewer, eds) Physicalism and Its Discontents. Cambridge University Press, 2001.
- David Papineau, Phenomenal and perceptual concepts. In (T. Alter & S. Walter, eds) Phenomenal Concepts and Phenomenal Knowledge: New Essays on Consciousness and Physicalism. Oxford University Press, 2006.
- John Perry. Knowledge, Possibility, and
Consciousness. MIT Press, 2001.
- John Perry. Response to commentators. Philosophy and Phenomenological Research, January 2004.
- Mark Rowlands, Consciousness and supervenience. In The Nature of Consciousness. Cambridge University Press, 2002.
- Stephen Schiffer, Mental content and epistemic two-dimensional semantics. Pacific APA. March 2002.
- Sydney Shoemaker, On David Chalmers' The Conscious Mind
. Philosophy and Phenomenological Research 59:539-44, 1999.
- Paul Skokowski. "I, zombie". Consciousness and Cognition 11:1-9, 2002.
- Tamler Sommers, Of zombies, color scientists, and floating iron bars. PSYCHE 8(22), 2002.
- Robert Stalnaker, What is it like to be a zombie? In (T. Gendler & J. Hawthorne, eds) Conceivability and
Possibility. Oxford University Press, 2002.
- Robert Stalnaker, On considering a possible world as actual. Proceedings of the Aristotelian Society, Supplementary Volume, 2001.
- Scott Sturgeon, Zombies and ghosts. Chapter 5
of Matters of Mind. Routledge, 2000.
- Nigel Thomas, Zombie killer. In (S. Hameroff, A. Kaszniak, & A. Scott, eds) Toward
a Science of Consciousness II. MIT Press, 1998.
- Robert van Gulick, Conceiving beyond our means: The limits of thought-experiments. In Toward a Science of Consciousness III. MIT Press, 2000.
- Bram van Heuveln, Eric Dietrich, & Michiharu
Oshima, Let's dance! The equivocation in Chalmers' dancing qualia argument.
Minds and Machines 8:237-49, 1998.
- Tillmann Vierkant, Zombie Mary and the blue banana. PSYCHE 8(19), 2002.
- Sara Worley, Conceivability, possibility, and physicalism. Analysis 63:15-23, 2003.
- Stephen Yablo, Concepts and consciousness. Philosophy and Phenomenological Research 59:455-63, 1999.
- Stephen Yablo, Coulda, woulda,
shoulda. In (T. Gendler & J. Hawthorne, eds)
Conceivability and Possibility. Oxford University Press,
2002.
- Stephen Yablo, Textbook Kripkeanism and the open texture of concepts. Pacific Philosophical Quarterly 81:98-122, 2000.
Other articles: Some other published or presented articles addressing my work, which I may or may not respond
to at some point:
- Fred Adams and Ken Aizawa,The bounds of cognition. Philosophical Psychology 14:43-64, 2001.
- Peter Alward, Is phenomenal pain the primary intension of 'pain'. Metaphysica 5:15-28, 2005.
- Katalin Balog, In defense of the phenomenal concept strategy. Philosophy and Phenomenological Research.
- Paul Bloomfield, Let's be realistic about serious metaphysics. Synthese, forthcoming.
- Nick Bostrom, Quantity of experience: brain duplication and degrees of consciousness. Minds and Machines 16:185-200, 2006.
- Glenn Braddock, Against Chalmers' epiphenomenalism. Auslegung 24:45-63, 2001.
- Daniel Bratcher, David Chalmers' arguments for "property dualism". Philosophy Today 43:292-301, 1999.
- Curtis Brown, Implementation and indeterminacy. Conferences in Research and Practice in Information Technology 37:27-31, 2004.
- Peter Carruthers, Reductive explanation and the 'explanatory gap'. Canadian Journal of Philosophy 34: 153-74. 2004.
- Peter Carruthers and Benedicte Veillet, The phenomenal concept strategy: A reply to Chalmers. Journal of Consciousness Studies 14:212-236, 2007.
- Chhanda Chakraborti, Metaphysics of consciousness and David Chalmers' property dualism. Journal of the Indian Council of Philosophical Research, 19:59-84, 2002.
- Christian Cocos, Computational processes: A response to Chalmers and Copeland
- Allin Cottrell, Sniffing the camembert: On the conceivability of zombies. Journal of Consciousness Studies 6:4-12, 1999.
- Louis deRosset, Reference and response. Australasian Journal of Philosophy.
- Esa Diaz-Leon. Can phenomenal concepts explain the epistemic gap? Mind, forthcoming.
- Esa Diaz-Leon, Reductive explanation, concepts, and a priori
entailment. Philosophical Studies, forthcoming.
- Eric Dietrich and Anthony Gillies, Consciousness and the limits of our imaginations". Synthese 126:361-81, 2001.
- Janice Dowell, A priori entailment, conceptual analysis, and making room for type-C physicalism. Australasian Journal of Philosophy, 2008.
- Janice Dowell, Serious metaphysics and the vindication of explanatory reductions. Philosophical Studies, 2008.
- Crawford Elder, Kripkean externalism versus conceptual analysis, Facta Philosophica 5:75-86, 2003.
- Keith Frankish, The anti-zombie argument. Philosophical Quarterly 57(229), 2007.
- Brian Jonathan Garrett, Causal essentialism versus the zombie worlds, Canadian Journal of Philosophy 39:93-112, 2009.
- Brian Jonathan Garrett, What the history of vitalism teaches us about consciousness and the "hard problem". Philosophy and Phenomenological Research 72:576-88, 2006.
- Brie Gertler, Overextending the mind? In (B. Gertler and L. Shapiro, eds) Arguing About the Mind, 2007.
- Rebecca Roman Hanrahan, Consciousness and modal empiricism. Philosophia 37:281-306, 2009.
- William Hasker, How not to be a reductivist. Progress in Complexity, Intelligence, and Design 2.3, 2003.
- John Hawthorne, Blocking definitions of materialism. Philosophical Studies 110:103-13, 2002.
- Jeffrey Hershfield, A note on the possibility of silicon brains and fading qualia. Journal of Consciousness Studies 9:25-31, 2002.
- Robert Howell, The
two-dimensionalist reductio. Pacific Philosophical
Quarterly 89:348-358, 2008.
- Charles Huenemann, The sage meets the zombie: Spinoza's wise man and Chalmers' The Conscious Mind. Studia Spinozana 14:21-33. 1998.
- Rene Jagnow, Shadow-experiences and the phenomenal structure of colors. Dialectica 64:187-212, 2010.
- Mark Jago, Logical information and epistemic space. Synthese 167, 2009.
- Jesper Kallestrup, Physicalism, conceivability, and strong necessities. Synthese, forthcoming.
- Amy Kind, The irreducibility of consciousness. Disputatio 19, 2005.
- Janet Levin, Taking type-B materialism seriously. Mind and Language 23:402-25.
- Joseph Levine, The Q-factor: Modal rationalism versus modal autonomism. Philosophical Review.
- William Lycan, Vs. a new a priorist argument for dualism. Philosophical
Issues 13:130-47, 2003.
- Michael Lynch, Zombies and the case of the phenomenal pickpocket. Synthese 149:37-58, 2006.
- Ausonio Marras, Consciousness and reduction. British Journal for the Philosophy of Science 56:335-61, 2005.
- Peter Marton, Zombies vs materialists: The battle for conceivability. Southwest Philosophy Review 14:131-38, 1998.
- Wallace Matson, Zombies begone! Against Chalmers' mind-brain dualism. New School Graduate Faculty
Philosophy Journal 24:123-136, 2003.
- Victoria McGeer, The trouble with Mary. Pacific Philosophical
Quarterly 84:384-93, 2003.
- Nenad Miscevic, Apriority and conceptual kinematics. Croatian Journal of Philosophy 1:21-48, 2001.
- Frederick Mills, The easy and hard problems of consciousness: A Cartesian
perspective. Journal of Mind and Behavior 19:119-40, 1998.
- Yujin Nagasawa, The knowledge argument against dualism. Theoria 63: 205-23, 2002.
- Christian Nimtz, Two-dimensionalism and natural kind terms. Synthese 138:125-48, 2004.
- Brendan O'Sullivan. Taking referentialism seriously: A response to the modal argument. Theoria 76:54-67, 2010.
- Michael Pauen, Painless pain: Property dualism and the causal role of phenomenal consciousness. American Philosophical Quarterly 37:51-63, 2000.
- Karol Polcyn, Conceivability, possibility, and a posteriori necessity: On Chalmers' argument for dualism. Diametros 7:37-55, 2006.
- Thomas Polger, H2O, water, and transparent reduction. Erkenntnis 69, 2008.
- Paul Raymore, A materialist response to David Chalmers' The Conscious Mind. The Dualist vol. 4, 1997.
- Sonia Roca-Royes, Conceivability and de re modal knowledge. Nous.
- Don Ross, Chalmers' naturalistic dualism: The irrelevance of the mind-body problem to the scientific study of consciousness. In (C. Erneling & D. Johnson, eds) The Mind as a Scientific Object. Oxford University Press, 2005.
- Anthony Rudd, Phenomenal judgment and mental causation. Journal of
Consciousness Studies 7:53-66, 2000.
- Matthias Scheutz, Causal versus computational complexity. Minds and Machines 11:534-66, 2001.
- Stephen Schiffer, Two-dimensional semantics and propositional attitude
content. In The Things We Mean. Oxford University Press, 2003.
- Laura Schroeter, Considering empty worlds as actual. Australasian Journal of Philosophy 83:331-37, 2005.
- Laura Schroeter, Gruesome diagonals. Philosophers' Imprint 3(3), 2003.
- Laura Schroeter, The rationalist foundations of Chalmers'
two-dimensional semantics. Philosophical Studies 18:227-55, 2004.
- J.J.C. Smart, Consciousness and awareness. Journal of Consciousness Studies 11:41-50, 2004.
- Jeff Speaks,
Epistemic two-dimensionalism and the epistemic argument. Australasian Journal of Philosophy 88:59-78, 2010.
- Scott Sturgeon, Apriorism about modality. In (B. Hale and A. Hoffmann, eds) Modality: Metaphysics, Logic, and Epistemology.
- Anand Vaidya, Modal rationalism and modal monism. Erkenntnis, 2008.
- Markos Valaris, Two-dimensionalism
and the epistemology of recognition. Synthese, 2008.
- Hamid Vahid, Conceivability and possibility: Chalmers on modal epistemology. Philosophical Explorations 9:243-260.
- Anand Jayprakash Vaidya, Understanding and essence, Philosophia, 2010.
- Brian Weatherson, Morality
in fiction and consciousness in imagination. Pacific APA, March
2004.
- Gene Witmer, Conceptual analysis, circularity, and the commitments of
physicalism. Acta Analytica 16:119-33, 2001.
- Gene Witmer, Supervenience physicalism and the problem of extras. Southern Journal of Philosophy 37:315-31, 1999.
Journal of Consciousness Studies symposium
on the "hard problem". (Articles by Baars,
Bilodeau, Churchland, Clark, Clarke, Crick
& Koch, Dennett,
Hameroff &
Penrose, Hardcastle, Hodgson, Hut
& Shepard, Libet, Lowe, MacLennan,
McGinn, Mills, O'Hara & Scutt, Price, Robinson, Rosenberg, Seager,
Shear, Stapp, Varela, Velmans,
Warner.)
*Philosophy and Phenomenological
Research symposium on The Conscious Mind. (Articles by Hill
& McLaughlin, Loar, Shoemaker, Yablo.)
Reviews of The Conscious Mind.
See my page of reviews
of The Conscious Mind. See also response
to Papineau (TLS), response
to Mulhauser (PSYCHE), response
to Searle (NYRB), second
response to Searle.
Katalin Balog, Conceivability, possibility,
and the mind-body problem.Philosophical Review108:497-528, 1999.
Balog appeals to zombies in order show that Jackson's and my
anti-materialist arguments are self-defeating. She argues that a
zombie could make the same arguments, with true premises but a false
conclusion (materialism is true in the zombie world), and concludes
that the arguments are invalid. She locates the problem in the
inference from conceivability to possibility, or in the thesis that
materialism requires a priori entailment.
This is an intriguing argument, but I think the problem with it is
clear. Balog's parallel argument requires that a zombie's claim
"I am conscious" is true; otherwise the argument
doesn't get off the ground. Balog supports this by suggesting that the
zombie's "consciousness" concept will pick out a
physical/functional property to which it is causally related. But I
think it is much more plausible that the zombie's claim is
false. The easiest way to see this is to consider an argument
in the zombie world, perhaps between Zombie Chalmers and Zombie
Dennett. Zombie Chalmers says "Qualia exist", Zombie Dennett
says "Qualia do not exist". Balog's analysis implies that
in the zombie world, Zombie Chalmers is right. But this seems
wrong. Surely in the zombie world, at least, Zombie Dennett is
right.
See "The
Content and Epistemology of Phenomenal Belief" for more on this sort of
thing.
Tim Bayne, Chalmers
on the justification of phenomenal judgment. Philosophy
and Phenomenological Research 62:407-19.
Bayne focuses on the epistemological discussion in Chapter 5 of
my book. There I argue that a reliabilist account of phenomenal
knowledge can't work, since a reliabilist account can't deliver
certain knowledge. When knowledge is grounded only in a reliable
connection, we can't be certain that the reliable connection holds, so
we can't rule out alternative skeptical scenarios; but we are certain
that we are conscious, and can rule our alternative skeptical
scenarios. Bayne argues that the same applies to my "acquaintance"
account. He notes that I accept in the book that acquaintance alone
doesn't suffice for full justification (acquaintance alone is
compatible with fallibility, e.g. in cases of inattention, etc). So
various further "background conditions" (e.g. concerning attention,
etc) are required for full justification. But we can't know for
certain that those background conditions hold; so we can't know for
certain that we are justified. So by parity of reasoning, the
acquaintance model can't deliver certain phenomenal knowledge, either.
I think this argument rests on a natural misreading of my
discussion of reliabilism. The argument is not: reliabilism
can't deliver certainty that we are fully justified, certainty that we
are fully justified is required for certainty, so reliabilism can't
deliver certainty. That argument would rest on a problematic "CJ"
thesis (analogous to the "KJ" thesis that knowledge requires knowledge
that one is justified, but with certainty instead of knowledge).
Rather, the argument is: when knowledge is grounded only in a reliable
connection, we can't be certain that the reliable connection holds, so
we can't rule out alternative skeptical scenarios about what's at the
other end of the connection, so we can't have certain knowledge.
The first argument (resting on the CJ thesis) just might deliver an
analogous argument against the acquaintance model. But I'll respond
by denying the CJ thesis (even accepting CJ, one could also argue that
"positive" certainty of justification doesn't require "negative"
infallibility). And an argument analogous to the second argument
won't work. Even if an acquaintance theorist accepts that we can't be
certain that we are justified, that merely shows that one can't rule
out skeptical scenarios in which one's belief in the experience is not
fully justified; it doesn't show that one can't rule out skeptical
scenarios in which the experiences are not present. Presumably an
acquaintance theorist can hold that we're certain about qualia but not
about such cognitive matters as full justification, so that we can
rule out skeptical scenarios without qualia, but not those without
full justification. (To resist this would require the dubious CJ
claim.) The analogous move is not open to a reliabilist: by its
nature, reliabilism can never deliver "knowledge beyond
skepticism". Again, see
"The
Content and Epistemology of Phenomenal Belief" for more.
*George Bealer, Modal epistemology and the rationalist renaissance. In (T. Gendler and J. Hawthorne, eds) Conceivability and Possibility. Oxford
University Press, 2002.
Bealer makes a number of arguments against the two-dimensional
approach to semantics and modal epistemology. His first argument
rests on a common misunderstanding: he says I hold that expressions
are ambiguous between primary and secondary intensions. This is not
my view: rather, I think that expressions have a complex semantic
value involving both intensions. (Cf: Frege held that expressions
have both sense and reference, without thinking they are ambiguous.)
Relatedly, he thinks the two-dimensionalist must deny that there are
necessary a posteriori propositions (e.g. that Hesperus is
Phosphorus). But the two-dimensionalist can accept this, as long as
propositions have (at least) two-dimensional structure. Some of the
confusion here may arise from my use (in The Conscious Mind) of
"primary proposition", for the primary intension of sentences, and likewise
for secondary intensions.
This was just terminological, working under the stipulation that
"propositions" are sets of worlds, but it can cause confusion when
someone uses "proposition" with other commitments, as Bealer does
(e.g. to pick out the semantic value of sentences, or the referent of
'that'-clauses). I now think it's better to stick with "intension",
and leave the nature of propositions (in the more general sense) as a
further question.
Bealer also says that the claim that "water" picks out XYZ relative to
some worlds considered as actual is a violation of English, because
the English expression picks out H2O in all worlds. But the latter
theoretical claim is wholly grounded in intuitive claims about the
referent of "water" in subjunctively considered counterfactual
situations, and these claims about subjunctive evaluation are
perfectly compatible with the claims that "water" behaves as I say it
does under epistemic evaluation. He also worries about the claim that
"water" picks out something other than water in some centered worlds
considered as actual. This and most of the semantic issues that
Bealer discusses are addressed in "On
Sense and Intension", especially the second half of section 7.
(N.B. None of these semantic points bear on the modal epistemology.
Bealer gives no argument against the claim that expressions can be
associated with intensions in the way I describe (whether or not this
association is "semantic"), and he gives no argument against the
thesis e.g. that a posteriori sentences have 1-intension that is false
in some world. This is all that is needed for the modal
framework.)
Bealer also addresses the use of the 2-D framework to argue against
physicalism, arguing that it fails because physical terms have
different primary and secondary intension. In The Conscious
Mind I suggested that these terms have the same intensions; in
more recent work I deny this. But either way (as pointed out in the
book and in recent work), this loophole leads only to the view I call
"type-F monism" or "panprotopsychism". (Bealer doesn't like the
latter term, but it's the view rather than the term that matters.)
I've never claimed to have an argument against this view, and in fact
am sympathetic to it, so there is no objection here. The
formalization of the argument given in the appendix of "Does Conceivability Entail
Possibility" and section 6 of Consciousness and Its Place in Nature"
makes all this pretty clear.
Bealer puts forward his own positive view, which appeals to
"semantically stable" expressions to close the gap between apriority
and necessity. I think this doesn't quite work: for reasons discussed
in section 5(v) of DCEP
and in "The Foundations of 2-D
Semantics", some semantically stable sentences are necessary a
posteriori. Also, the best anti-materialist conclusion one can get
from this strategy is a rejection of psychophysical property
identities, but that rejection is compatible with the truth of many
other robust forms of materialism. Still, with a few adjustments,
Bealer's appeal to semantic stability is in fact quite compatible with
a two-dimensional approach.
Mark Bishop, Dancing with pixies: Strong artificial intelligence and panpsychism. In (J. Preston and J.M. Bishop, eds) Views into the Chinese Room. Oxford University Press, 2002.
Mark Bishop, Counterfactuals cannot count: A rejoinder to David Chalmers. Consciousness and Cognition, 11:642-52, 2002.
In both of these papers, Bishop advances a version of Putnam's
argument that every ordinary system implements every computation, uses
this to argue that computation can't be the basis of consciousness,
and then addresses my response to Putnam. I've argued (e.g. in "Does a Rock Implement Every Finite-State
Automaton") that Putnam's systems are not true implementations,
since they lack appropriate counterfactual sensitivity. Bishop
responds that mere counterfactual sensitivity can't make a difference
to consciousness: surely it's what actually happens to a system that
matters, not what would have happened if things had gone differently.
He runs a version of the fading qualia argument, suggesting that we
can remove unused state-transitions one-by-one, thus removing
counterfactual sensitivity, while (he argues) preserving consciousness.
In response: it's not at all obvious just how the gradual
transition will work in a combinatorial state-automaton, but let's
grant that something like it is possible. Then this process will
gradually transform a counterfactually-sensitive system into a
"wind-up" system that implements just one run. This plausibly will
affect the system's cognitive states (such as beliefs), gradually
destroying them, so the fading qualia argument (which relies on
preserving cognitive states) doesn't apply. Bishop addresses a
version of this point by saying that "input sensitivity" can't be
crucial, since a non-input-sensitive system (e.g. a blind system, or
one with constant input signals) could be conscious. But what really
matters is counterfactually-sensitive cognitive processes, which the
blind system still has (it isn't a wind-up system). Compare an
ordinary human, a blind human, and a humanoid system preprogrammed to
go through a single specific series of brain states. Here it seems
most plausible to say that the first two systems are conscious but
that the third is not.
Maybe it is initially hard to see just how mere counterfactual
sensitivity can affect an intrinsic property such as consciousness.
But it's hard to see how any physical property can affect
consciousness. Given that the connection between physical properties
and consciousness is contingent, the hypothesis that some of the
relevant physical properties are dispositional rather than categorical
doesn't seem all that hard to accept. And it seems to fit well with
our intuitive ascriptions of consciousness.
*Ned Block and Robert Stalnaker, Conceptual
analysis, dualism, and the explanatory gap. Philosophical Review 108:1-46, 1999.
Frank Jackson and I have written a response to this article:
"Conceptual
Analysis and Reductive Explanation" (Philosophical Review 110: 315-61, 2001).
*Andrew Botterell, Conceiving what is not there. Journal of Consciousness
Studies 8:21-42, 2001.
Botterell responds to the conceivability argument, in two parts.
First, he says that whether one disambiguates conceivability of S as
"one sees that S is possible" or "it appears that S is possible", the
argument doesn't work. In the first sense, it's not clear that
zombies are conceivable; in the second sense, there are gaps between
conceivability and possibility. Response: the notion of
conceivability (ideal primary positive conceivability) that I appeal
to is neither of these: see "Does
Conceivability Entail Possibility". Second, Botterell suggests
that the 1-possibility of zombie worlds doesn't entail their
2-possibility, because physical terms may have different primary and
secondary intensions. I think that's right, but it leads only to
"panprotopsychism" or type-F
monism. Botterell says that this is a form of physicalism. I
don't mind if one talks that way, as long as one is clear on just what
sort of physicalism it is.
*David Braddon-Mitchell. Qualia and
analytic conditionals. Journal of Philosophy 100:111-35, 2003.
This paper tries to explain the conceivability of zombies in a
manner compatible with physicalism. It argues that terms such as
"qualia" function so that it's analytic that if there are special
nonphysical properties with which we're acquainted, those are qualia,
and otherwise, certain functional properties are qualia. Then it's
conceivable that zombies are possible, because it's conceivable that
the actual world has the special nonphysical properties. But as long
as our world doesn't actually have those properties, then qualia are
physical all the same.
My reply to this is basically the same as my reply to the very
similar arguments by Hawthorne and Stalnaker below. At best, this semantic
hypothesis explains why it is conceivable that a zombie world is
metaphysically possible. But the key conceivability claim was not
this but rather that it is conceivable that a zombie world is actual
(i.e. P&~Q is not ruled out a priori, where P is the microphysical
truth about our world and Q is the claim that someone has qualia). If
this conceivability claim is correct, Braddon-Mitchell's semantic
hypothesis is false (as this hypothesis entails that P&~Q is ruled out
a priori). Braddon-Mitchell responds very briefly by simply denying
the conceivability claim, but he gives no argument for this denial of
what seems to be an intuitive datum. The view has equal trouble
accommodating the apparent epistemic datum in the knowledge argument.
Braddon-Mitchell suggests at one point that his hypothesis is
reasonable because if we discovered that our world were entirely
physical (if an oracle told us this, for example), we would not then
deny that qualia exist, but would say that qualia are physical. I
agree that we would do this, but I don't think this provides any
support for Braddon-Mitchell's hypothesis. Our reaction in this case
would clearly be an inference from our knowledge that qualia exist,
and this knowledge is a posteriori. If this a posteriori knowledge
were somehow suspended, there would be no good reason to make the
inference. If so, there is no a priori entailment from the
claim that our world is purely physical to the claim that qualia
exist.
(Update: see also the discussion in section 5 of "The Two-Dimensional Argument Against Materialism".)
*Anthony Brueckner. Chalmers' conceivability argument for dualism. Analysis 61:187-93, 2001.
This paper is a bit puzzling. It starts by saying that others
have misunderstood my argument, and then gives a reasonably (though
not completely) accurate reconstruction of some aspects of my
two-dimensional modal argument. Then in the last section Brueckner
says that I don't establish that the conceivability of zombies entails
the relevant possibility. But this is a straightforward consequence
of the independently argued thesis that conceivability in the relevant
sense entails possibility of primary intension (which is all I need).
Brueckner doesn't even discuss my positive case for this thesis, so
something has gone awry -- I'm not sure what. It may be that the
argument in the book was insufficiently formal and explicit; people
have misunderstood it more often than I expected. There is a more
formal version, and a defense of the relevant thesis, in "Does
Conceivability Entail Possibility" (see especially the
appendix).
*Alex Byrne, Cosmic
hermeneutics. Philosophical Perspectives 13:347-83, 1999.
Byrne argues against the a priori entailment of most
macro facts by micro facts. Along the way it addresses two of my
arguments: the argument from conceivability, in which I argue that a
scenario in which the micro facts are the same but the macro facts are
different is inconceivable; and one of the arguments from
epistemology, in which I argue that a good enough reasoner given only
the micro facts would be in a position to ascertain the macro facts.
Byrne's main objection to the conceivability argument is that given
that we don't yet know just what the micro facts are, we can't know
that the scenario in question is inconceivable. His main objection to
the epistemological argument is that the strategy I outline relies on
the reasoner reaching certain intermediate high-level conclusions, and
that the entailment of these conclusions is just as questionable as
the entailment of the original macro facts.
I think Byrne misses a key aspect of the arguments in the book
(which are admittedly brief). The argument in general is to argue
that the micro facts specify micro structure and dynamics, that micro
structure and dynamics a priori entail macro structure and
dynamics, and that macro structure and dynamics entails most macro
facts (except those that depend on mentality or indexicals). The
middle level of macro structure and dynamics can be thought of as a
"geometric" characterization of the structure and evolution of macro
objects -- their overall shapes, masses, positions, causal relations,
etc. As long as microphysics has information about mass, position,
etc, of micro objects, the information about macro objects will be
easily derivable from the micro information (e.g. by considerations
about macroscopic mass densities in various locations, and so on). So
this point is robust over microphysical theories. The second
entailment is made plausible not least by the fact that this sort of
macro structure and dynamics (plus facts about appearance, which I can
also help myself to) is all the information we have to go on in
ordinary perception.
Byrne's objection to the conceivability argument can be rebutted by
noting that however microphysics turns out, it will be inconceivable
that there be the microstructure without the macrostructure, and it
will be inconceivable that there be the macrostructure without the
macro facts. His objection to the epistemological argument can be
rebutted by noting that the reasoner will easily be able to ascertain
facts about macrostructure, and from facts about macrostructure (plus
facts about appearance) they will be able to ascertain the macro facts
in question (just as we can through perceptual information). Byrne
does not address my second epistemological argument, which is that the
absence of a priori entailment of macro facts will lead to a sort of
skeptical problem concerning those macro facts (two epistemic
possiblities with the same micro facts and different macro facts would
"look" just the same) that we are not in fact faced with in most
cases, except in the case of consciousness. All this is now discussed
at greater length in "Conceptual Analysis and Reductive Explanation".
*Alex Byrne, Chalmers on epistemic content. SOFIA conference on Metaphysics of Mind, December 2001.
Byrne suggests that my 2-D account of content entails that we can't
think about external objects, where a thought is about an object when
its truth-value in a world depends on its properties in a world. The
1-intension of concepts like Fred pick out different
individuals in different worlds, so the truth-value of the epistemic
of Fred-thoughts at a world doesn't depend on Fred's properties
there, so our Fred thoughts aren't about Fred.
In response: I wouldn't use "think about an object" this way. On
normal usage, thinking about an object requires that the object be the
extension of a concept involved in a thought (and maybe requires a bit
more, such as acquaintance), but there's no rigidity requirement.
Nevertheless I think we can come halfway to satisfying Byrne's
requirement. The 2-intensions of our concepts of external objects can
be rigid, although the 1-intensions usually cannot: one might say that
such concepts can be subjunctively rigid but not epistemically rigid.
I don't think this is counterintuitive, or has bad consequences.
Byrne doesn't really suggest any bad consequences, apart from saying
that it seems wrong to say we can't think about (e.g.) Bismarck. I
agree that seems wrong, but I think that's a problem with a reading of
"think about" that requires epistemic rigidity, not a problem with my
account.
Byrne suggests that the account divides epistemic space in the wrong
way. Say that W1 is a world where the primary intension of "Chalmers"
picks out Russell, who is a philosopher, and in which Chalmers himself
is not a philosopher. Then on my account, the epistemic content of
"Chalmers is a philosopher" is true at the scenario W1, but Byrne
thinks that it ought to be false there, or at least that it would be
false if the thought were truly about Chalmers. I agree that it would
be false there if the thought were "about Chalmers" in the sense
requiring epistemic rigidity, but I don't think this applies to the
ordinary sense. Intuitively, "Hesperus" and "Phosphorus" thoughts
are both about Venus, but it's epistemically possible that Hesperus is not Phosphorus, and intuitively there are points in
epistemic space (although perhaps not in subjunctive space) at which
the thought is false. So Byrne's suggested connection between
"thinking about an object" (in the ordinary sense) and divisions of epistemic space seems too
strong.
*Alex Byrne, Intentionalism defended. Philosophical Review 110:199-240, 2002.
In section 9 of this paper, Byrne criticizes my "fading qualia"
argument against intentionalism. This is a bit perplexing, as the
fading qualia argument isn't an argument against intentionalism, but
an argument for (nonreductive) functionalism. One could if one likes
use it to argue against reductive functionalism, though there are
better ways to do that. But there's no good argument against
intentionalism here (largely for the reasons Byrne gives), and my
discussion never mentions intentionalism. (I also never say that "the
external world seems as bright as ever" to a subject with faded
qualia; as Byrne says, that description seems plainly wrong). In fact
I'm quite sympathetic with intentionalism, of the nonreductive
variety: see "The Representational
Character of Experience".
Alex Byrne and Ned Hall, Chalmers on consciousness and quantum mechanics. Philosophy of Science 66:370-90, 1999.