Descartes, Conceivability, and Mirroring Arguments

Yesterday, as part of a panel on machine consciousness, I saw Jack Copeland deliver a razor-sharp talk based on a paper that he published last year with Douglas Campbell and Zhuo-Ran Deng, entitled “The Inconceivable Popularity of Conceivability Arguments“.  To give you an idea of what the paper is about, I reproduce the abstract here:

Famous examples of conceivability arguments include: (i) Descartes’ argument for mind-body dualism; (ii) Kripke’s ‘modal argument’ against psychophysical identity theory; (iii) Chalmers’ ‘zombie argument’ against materialism; and (iv) modal versions of the ontological argument for theism. In this paper we show that for any such conceivability argument, C, there is a corresponding ‘mirror argument’, M. M is deductively valid and has a conclusion that contradicts C’s conclusion. Hence a proponent of C—henceforth, a ‘conceivabilist’—can be warranted in holding that C’s premises are conjointly true only if she can find fault with one of M’s premises. But M’s premises—of which there are just two—are modeled on a pair of C’s premises. The same reasoning that supports the latter supports the former. For this reason a conceivabilist can repudiate M’s premises only on pain of severely undermining C’s premises. We conclude on this basis that all conceivability arguments, including each of (i)—(iv), are fallacious.

It’s a great paper, but I’m not sure the mirroring move against Descartes works, at least not as it is expressed in the paper.  Although the text I quote below is from the paper, I composed this objection while listening to (and recalling) the talk.  I apologise if the paper itself, which I have not read carefully to the end, blocks or anticipates the move I make here (please let me know if it does).

First, the paper defines CEP as the claim that conceivability entails possibility:
(CEP) ⬦cψ→⬦ψ
Descartes then is quoted:
“I know that everything which I clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it. Hence the fact that I can clearly and distinctly understand one thing apart from another is enough to make me certain that the two things are distinct, since they are capable of being separated, at least by God… [O]n the one hand I have a clear and distinct idea of myself, in so far as I am simply a thinking, non-extended thing; and on the other hand I have a distinct idea of a body, in so far as this is simply an extended, non-thinking thing. And accordingly, it is certain that I am really distinct from my body, and can exist without it.”(Cottingham, Stoothoff, & Murdoch, 1629, p. 54)
Then it is claimed that Descartes uses CEP:
“Setting φ, ψ, and μ as follows:
φ: Mind=Body
ψ: MindBody
μ: (MindBody),
we get:
D5. ¬(Mind=Body)
Here Descartes uses a (theistic) version of CEP to infer that it is possible for mind and body to be distinct. From this he infers they are actually distinct. Why does he think he can make this move from mere possibility to actuality? Presumably because he is assuming D3, or something like it, as a tacit premise (Robinson, 2012).”
But that reasoning is questionable.  Surely none of D1-4 are equivalent to CEP.  So what the authors must mean is that one of D1-4 (i.e., D2) relies on CEP.  But in the quoted passage, Descartes does not appeal to (or argue for) CEP.  Rather, he argues for a more restricted claim, one that more closely resembles D2 in structure, in that it infers specifically the possibility of distinctness from the conceivability of distinctness.  That is, rather than CEP, it seems to me that Descartes argues for, and uses, CDEPD (Conceivability of Distinctness Entails Possibility of Distinctness) :
(CDEPD) ⬦c(φψ) (φψ)
It is prima facie possible to hold CDEPD without holding CEP.  Further, there are arguments (such as the one Descartes puts forward in the quoted passage), that support CDEPD that do not prima facie support CEP.  That is, one can accept what Descartes says in the quoted passage, but, it seems, reject any attempt at an analogous (dare I say “mirroring”?) argument:
Hence the fact that I can clearly and distinctly understand one thing as being the same as another is enough to make me certain that the two things are the same, since they are capable of being ?, at least by God.
What could we put in place of the question mark to yield a proposition that is true?  To yield a proposition that is implied by what Descartes says in Meditations or elsewhere?  To yield a proposition that is required for Descartes’s conceivability argument to proceed?
There seems to be an asymmetry here between the conceivability of difference and the conceivability of sameness that allows Descartes to get by with CDEPD, rather than having to employ CEP.
Why does this matter?  It matters because the mirroring argument the authors make against Descartes effectively says:  “Descartes helped himself to CEP, so we can do the same.  Only instead of applying the CEP to a proposition about the conceivability of differences, we will apply it to a proposition about the conceivability of sameness.”  If what I have said above is right, then it is possible that Descartes was not helping himself to CEP in general, but to a more restricted claim about propositions involving distinctness, CDEDP.  Thus a mirroring argument would not be able to help itself to CEP, and thus would not be able to derive the required, contrary conclusion that way.  Further, there is no way to derive such a contrary conclusion using CDEDP instead.  So the mirroring argument against Descartes’s conceivability argument fails.
I have not yet checked to see if there are similar moves that Kripke and Chalmers can make to “break the mirror” in their respective cases.

Roles for Morphology in Computation



From Pfeifer, Iida and Lungarella (2014)

Tomorrow I’m giving an invited talk in Gothenburg at the Symposium on Morphological Computing and Cognitive Agency, as part of the The International Society for Information Studies Summit 2017 (entitled — deep breath — “DIGITALISATION FOR A SUSTAINABLE SOCIETY: Embodied, Embedded, Networked, Empowered through Information, Computation & Cognition!”).  Here’s my title and abstract:

Roles for Morphology in Computation

The morphological aspects of a system are the shape, geometry, placement and compliance properties of that system. On the rather permissive construal of computation as transformations of information, a correspondingly permissive notion of morphological computation can be defined: cases of information transformation performed by the morphological aspects of a system. This raises the question of what morphological computation might look like under different, less inclusive accounts of computation, such as the view that computation is essentially semantic. I investigate the possibilities for morphological computation under a particular version of the semantic view. First, I make a distinction between two kinds of role a given aspect might play in computations that a system performs: foreground role and background role. The foreground role of a computational system includes such things as rules, state, algorithm, program, bits, data, etc. But these can only function as foreground by virtue of other, background aspects of the same system: the aspects that enable the foreground to be brought forth, made stable/reidentifiable, and to have semantically coherent causal effect. I propose that this foreground/background distinction cross-cuts the morphological/non-morphological distinction. Specifically, morphological aspects of a system may play either role.

The Symposium will be chaired by Rob Lowe, and Gordana Dodig Crnkovic, and the other speakers include Christian Balkenius, Lorenzo Magnani, Yulia Sandamirskaya, Jordi Vallverdú, and John Spencer (and maybe Tom Ziemke and Marcin Schroeder?).

I’m also giving an invited talk the next day (Tuesday) as part of a plenary panel entitled: “What Would It Take For A Machine To Have Non-Reductive Consciousness?”  My talk is entitled “Computation and the Fate of Qualia”.  The other speakers are Piotr Bołtuć (moderator), Jack Copeland, Igor Aleksander, and Keith W. Miller.

Should be a fantastic few days — a shame I can’t stay for the full meeting, but I have to be back at Sussex in time for the Robot Opera Mini-Symposium on Thursday!


Functionalism, Revisionism, and Qualia

logoA paper by myself and Aaron Sloman, “Functionalism, Revisionism, and Qualia” has just been published in the APA Newsletter on Philosophy and Computing. (The whole issue looks fantastic – I’m looking forward to reading all of it, especially the other papers in the “Mind Robotics” section, and most especially the papers by Jun Tani and Riccardo Manzotti). Our contribution is a kind of follow-up to our 2003 paper “Virtual Machines and Consciousness”. There’s no abstract, so let me just list here a few of the more controversial things we claim (and in some cases, even argue for!):

  • Even if our concept of qualia is true of nothing, qualia might still exist (we’re looking at you, Dan Dennett!)
  • If qualia exist, they are physical – or at least their existence alone would not imply the falsity of physicalism (lots of people we’re looking at here )
  • We might not have qualia: The existence of qualia is an empirical matter.
  • Even if we don’t have qualia, it might be possible to build a robot that does!
  • The question of whether inverted qualia spectra are possible is, in a sense, incoherent.

If you get a chance to read it, I’d love to hear what you think.


The existence of qualia does not entail dualism

Our next E-Intentionality seminar is this Thurnaossday, December 1st, at 13:00 in Freeman
G22.  This will be a dry run of a talk I’ll be giving
as part of EUCognition2016, entitled “Architectural Requirements for Consciousness”.  You can read the abstract here, along with an extended clarificatory discussion prompted by David Booth’s comments.

Multi-sensory integration without consciousness

This morning, Tad Zawidzki drew my attention to the publication on Tuesday of this paper: Multisensory Integration in Complete Unawareness. What Faivre et al report there is exactly the kind of phenomenon that Ryan Scott, Jason Samaha, Zoltan Dienes and I have been investigating. In fact, we have been aware of Faivre et al’s study and cite it in our paper (that is currently under review).

Their work is good, but ours goes further. Specifically, we show that:

  • a) Cross-modal associations can be learned when neither of the stimuli in the two modalities are consciously perceived (whereas the Faivre et al study relies on previously learned associations between consciously perceived stimuli).
  • b) Such learning can occur with non-linguistic stimuli.

Together, a) and b) really strengthen the case against accounts that assert that consciousness is required for multi-sensory integration (e.g., Global Workspace Theory). Some defenders of such theories might try to brush aside results like that of Faivre et al by revising their theories to say that consciousness is only required for higher-level cognition, such as learning; and/or by setting aside linguistic stimuli as a special case of (consciously) pre-learned cross-modal associations which can be exploited by unconscious processes to achieve the appearance of multi-sensory integration. Our results block both of these attempts to save (what we refer to as) integration theories.