On Philosophy

June 30, 2007

Kylie’s Puzzle, Externalism, and Consciousness

Filed under: Mind — Peter @ 12:00 am

Kylie’s puzzle can be considered a version of the McKinsey reductio of externalism (McKinsey, M. 1991: Anti-Individualism and Privileged Access. Analysis, 51, pp. 9–16). However I find it preferable philosophically to the McKinsey argument, at least in terms of simplicity, as it sidesteps issues of metaphysical dependence and concept agnosticism which tend to get dragged into any discussion of the McKinsey argument. Anyways, Kylie’s puzzle is as follows: Kylie entertains the thought that water is wet. Kylie also has reason to believe that content externalism is correct. Therefore Kylie concludes that she can only be thinking about water if she has lived in an environment in which water exists, and in which there is a community of language speakers that use “water” to designate water (plus whatever other twists your favorite variety of externalism may involve). Thus Kylie concludes that water must exist (and that she lives in an appropriate community, and so on). So Kylie has come to reason solely on the basis her first person experience of thinking that water is wet to the conclusion that the world contains water. But this is absurd, clearly Kylie can’t have reason to conclude that the world contains water on the basis of such a priori reasoning (consider various brain-in-a-vat type situations). Thus either externalism is false or we don’t have privileged first person access to our thoughts. And that is a dilemma, since content externalism seems well founded, but so is privileged first person access to our thoughts, as to deny that would be to essentially deny that consciousness exists (or at least consciousness as we know it).

The goal then is to find a way out that allows us to have both content externalism and privileged first person access to the contents of consciousness. But before I discuss my proposal let me first outline another possible way to resolve the puzzle proposed by Martin Davies and why I don’t think it completely resolves the dilemma (Davies, M. 2000: Externalism and Armchair Knowledge. In P. Boghossian and C. Peacocke (eds), New Essays on the A Priori. Oxford: Oxford University Press, 384–414). Davies’ proposal is that what we are dealing with in Kylie’s puzzle is a kind of begging the question. He compares it to Moore’s argument, that the existence of my hands proves that the world exists, saying that what both arguments have in common is that the first premise requires as its warrant the very thing that it seeks to prove. In Kylie’s puzzle, if externalism is true, then the existence of water is a precondition for the ability to think that water is wet. Thus the argument fails to justify concluding that water exists based only on a priori reasoning. Davies takes this as a resolution of the problems posed by the argument.

I would not dispute the validity of Davies analysis, but I would dispute that it really solves the problem at hand. The problem at hand is that the existence of such puzzles as Kylie’s seem to imply that externalism is incompatible with privileged first person access. And Davies’ solution to the problem is to postulate that thinking that water is wet is only possible if water exists. Which is all fine and good, but we don’t have privileged first person access to whether water exists. Which means in turn that we don’t have privileged first person access to whether we are thinking that water is wet. So Davies’ solution, while technically flawless, is really just a way of biting the bullet in this case.

I would rather look for a way out that doesn’t involve biting any bullets, but to do that I need to take a more detailed look at Kylie’s puzzle. Below is Kylie’s puzzle presented with a new convention, surrounding a word with brackets to refer to its content or reference. For example, [water] designates H2O, the natural kind that we call “water” in this world. (Of course in twin earth [water] would designate XYZ, but given that twin earth situations aren’t involved here we don’t need to take that into account.) The argument is as follows then
1. I think “[water] is wet”
2. I can only think “[water] is wet” if [water] exists
3. [water] exists
By describing the argument this way a possible problem becomes apparent, namely putting the content of “water”, [water], into the thought. Obviously since we accept content externalism what is thought, what our thoughts refer to, their content, depends at least in part on the external world. But obviously what they refer to isn’t apparent to us as we think them, otherwise we could know that water is H2O simply by reflecting on it. Let us designate our conception of water by {water}. The premise of externalism then is that {water} by itself doesn’t determine its content, and I am not trying to object to that, or slyly subvert it. In fact we should probably admit that given a language speaking community there are a number of facts governing which conceptions correspond to what content, and that these facts may vary from community to community. So in our community the fact that ({water}, [water]) is the case (that {water} means [water]) does not preclude the possibility of ({water}, [XYZ]) for some other community in some other place. Note that I always use the words we use to designate things in our language within [] and {}, for the sake of clarity.

Now we can rewrite the argument using this notation:
1. I think “{water} is wet”
2. I can only think “{water} is wet” if [water] exists
3. [water] exists
Note that in this formulation the argument is obviously invalid, or at least missing something. To make if valid we would have to add an additional premise, 1.5, that ({water}, [water]) is the case. But that is clearly a fact that is not available immediately to us, at least not with any confidence. In fact we might very well argue that we could never have such a thought, since that would require an ability to think about the content of terms directly, which seems impossible. (As far as I know it is only possible to think of things by conceiving of them to have certain properties or to be in certain relations to us, but this is not a line of thought I will pursue any farther at the moment.)

This solution allows us to accept both content externalism and the ability to have privileged first person access to our thoughts. However, we do have to make a few concessions. The first is the acceptance of what could be construed as a kind of narrow content, in this case {water}. The second is that we have to accept that the content of thought, so long as that content depends on external factors, is not part of consciousness. It is {water}, not [water] that is part of consciousness, and {water} doesn’t depend on anything external (it’s not even a thing, more like a mental representation). But I don’t think these sacrifices are too big given what we have to gain by making them.

Know of a great paper on the McKinsey-Brown argument? Leave me a comment.

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