Department of Philosophy
University of Arizona
Tucson, AZ 85721
[[Published in Behavioral and Brain Sciences 16:35-36, 1993, as a commentary on Alvin Goldman, The Psychology of Folk Psychology. ]]
In Section 5 of his interesting article, Goldman suggests that the consideration of imaginary cases can be valuable in the analysis of our psychological concepts. In particular, he argues that we can imagine a system that is isomorphic to us under any functional description, but which lacks qualitative mental states, such as pains and color sensations. Whether or not such a being is empirically possible, it certainly seems to be logically possible, or conceptually coherent. Goldman argues from this possibility to the conclusion that our concepts of qualitative mental states cannot be analyzed entirely in functional terms.
This thought-experimental methodology seems sound to me, and I agree with Goldman on the logical possibility of these absent-qualia cases (although many functionalists would not; e.g. Armstrong 1968, Dennett 1991, Shoemaker 1975). However, I think that this methodology can be taken further, yielding conclusions that oppose those that Goldman draws elsewhere in the article.
Consider: if it is logically possible that my functional isomorph might lack qualia entirely, it seems equally logically possible that there could be a qualia-free physical replica of me. We have already seen that there is no conceptual entailment relation from the functional properties of a system to the qualitative properties; it seems even clearer that there is no entailment relation from the non-functional implementational details to qualia. (What conceptual entailment could neurophysiological detail possibly provide that silicon, or even Chinese nations, could not?) So let's consider Zombie Dave, my qualia-free physical replica. Zombie Dave is almost certainly not an empirical impossibility, but he is a conceptual possibility.
First, let us ask: Does Zombie Dave have beliefs? It seems to me that he does. If we ask him where his car is, he'll tell us that it's in the driveway. If we ask him whether he likes basketball, he tells us that he does. If we tell him that there's a basketball game starting across town in half an hour, he'll immediately head for the driveway, an action that seems to be best explained by the hypothesis that he wants to go to the basketball game, believes that his car will get him there, and believes that his car is in the driveway. All of the usual principles of psychological explanation sanction attributing beliefs to Zombie Dave; explaining his action without the attribution of beliefs would be a fearsomely complex task. (It might be objected that Zombie Dave lacks the external grounding required for belief contents, but we can avoid this problem by stipulating that his environment and history are physically indistinguishable from mine.)
Goldman argues in Section 8 that beliefs, like perceptual states, are typically accompanied by qualia; but much more would be required to conclude that qualia are essential to a state's being a belief. (Searle (1990) has given an argument in this direction, but it does not seem to have been widely accepted.) Zombie Dave's beliefs may not be colored by the usual phenomenological tinges, but it seems reasonable to say that they are nevertheless beliefs. Beliefs, unlike qualia, seem to be characterized primarily by the role that they play in the mind's causal economy. (To illustrate the difference, note that it seems coherent to be an epiphenomenalist about qualia, whether or not one finds the position plausible; but there seems to be something conceptually wrong with the idea that beliefs could be epiphenomenal.) So qualia-free believers like Zombie Dave are quite conceptually coherent, and qualia don't seem to be an essential part of our concept of belief.
Even if one resists the idea that Zombie Dave has beliefs, we can still use him to show that qualia cannot be the primary mechanism in the self-ascription of our mental states. For Zombie Dave ascribes precisely the same mental states to himself as I do! By some process or other, he'll tell you that he thinks that Bob Dylan makes good music. How can this ability for self-ascription be explained? Clearly not by appealing to qualia, for Zombie Dave doesn't have any. The story will presumably have to be told in purely functional terms. But once we have this story in hand, it will apply equally to proud possessors of qualia such as ourselves. The self-ascription mechanisms that Zombie Dave uses are equally the mechanisms that we use; at most, the difference consists in the fact that his ascriptions might be wrong, whereas ours are right. Therefore there is no need to invoke qualia in the explanation of how we ascribe mental states to ourselves. Zombie Dave does the job, presumably, either by reasoning from non-qualitative evidence, or by simply being thrown into the appropriate state. It seems likely that we do it the same way, and that qualia are a red herring.
All this seems to lead to a rather epiphenomenalist view of qualia. Note, for instance, that the argument in the above paragraph doesn't apply only to the self-ascription of beliefs, but also to the self-ascription of qualia; so that qualia don't seem to play a primary role in the process by which we ascribe qualia to ourselves! (Zombie Dave, after all, ascribes himself the same qualia; it's just that he's wrong about it.) I am happy enough with the conclusion that qualia are mostly just along for the ride, but I suspect that Goldman and others will not be. It seems to me that the only way to avoid this conclusion is to deny that Zombie Dave is a conceptual possibility; and the only principled way to deny that Zombie Dave is a conceptual possibility is to allow that functional organization is conceptually constitutive of qualitative content. This is probably a step that Goldman doesn't wish to take, as it would negate many of his conclusions, but there may not be any tenable middle ground between functionalism and epiphenomenalism.
Armstrong, D.M. 1968. A Materialist Theory of the Mind. Routledge and Kegan Paul.
Dennett, D.C. 1991. Consciousness Explained. Little-Brown.
Searle, J.R. 1990. Consciousness, explanatory inversion, and cognitive science. Behavioral and Brain Sciences 13:585-642.
Shoemaker, S. 1975. Functionalism and qualia. Philosophical Studies 27:291-315.