Levine (1997) claims that Locating Consciousness (1995) does not seriously address the problem of the explanatory gap; instead it merely provides lots of data. Here I argue that, contrary to the intuitions of some philosophers, the best remedy for our gaps in explanation and understanding is in fact through empirical investigation.
2. So far, so good. However, Levine goes on to claim that (even if I might be right) I need to make some sort of philosophical argument for my view instead of presenting lots of empirical data. Here I get confused. My claim is that persons who believe that we cannot ever develop a scientific theory of consciousness assert that proposition only because their inchoate ideas about what consciousness is, how we might study it, what theories in cognitive science look like, and so on, are bad. The obvious solution -- at least it is obvious to me -- is to educate the ill-informed and then carry on the debate. Otherwise we are all just wasting our time.
3. That is why we need all the details and facts. In order to answer the question of whether a "scientific theory of information flow" can be a theory of consciousness (para. 4), we need to appreciate what the theory is and what we know about consciousness apart from the theory. Though there are philosophical issues bound up in this question to be sure, there are also important and direct empirical implications.
4. Suppose I announce that a scientific theory of glump will forever elude us. Before you can evaluate that claim, you would need to know, as much as possible, what glump is and how it functions in our world. My "a priori" intuitions about what I think glump is like are beside the point -- you need to know what it really is. Making empirical observations is one way to uncover glumpness. Arm-chair theorizing might ultimately help -- imagining what a world might be like without glump, whether glump could exist without the traditional glump instantiators, for example -- but surely we should only proceed with the thought experiments after we have learned all we can of the actual facts of the matter. Otherwise it isn't clear what we supposed to be imagining here.
5. Actually, I do not believe that Levine and I diverge too much on this point. Levine just feels the pull of the untutored intuitions more strongly than I. He notes that while conceivability may not have the strong metaphysical implications that some skeptics would like, it does have an important impact on what counts as an explanation. If we could conceive of not-X occurring under circumstances in which our putative scientific theory tells us that X should or must occur, then something is amiss with our story. Part of what it is to be a good explanation is to disallow us imagining the contrary.
6. So, for example, a good explanation of water as H2O presents us from being able to conceive of H2O as being anything but water. We might be able to imagine how someone who didn't really understand the basics of chemistry could think that H2O might be some other substance, but we ourselves cannot seriously entertain such possibilities in any detail or depth.
7. In contrast, Levine and others want to maintain, we can imagine beings identical to us physically but lacking consciousness. Hence there is a gap between our understanding that consciousness is a brain state and our ability to imagine (fully functioning) brains without awareness. Furthermore, "confidence that there is a metaphysically sufficient condition [for brains entailing consciousness], so long as we don't know how to characterize it, isn't enough to close the gap in our understanding" (para. 6).
8. It is true that confidence that some condition exists, without having an inkling what that condition is, will not deepen our understanding of the world. The whole point though is that once you do characterize the condition in enough detail, then whatever gap there was will now be closed. Saying H2O is sufficient for water will not prevent the determined from conceiving of H2O as some other liquid. However, fully understanding what hydrogen and oxygen are and how they interact -- embedding that statement in some sort of detailed scientific picture -- would be enough to close off the imaginative possibilities. (I present more of this argument in Hardcastle, 1996a).
9. The same should hold true for studies of consciousness. So long as we don't characterize the links between brains and minds in detail, then we will not have enough information to prevent our imagining what turns out to be something entirely impossible. Again, we need the empirical details before we can properly assess whether what we are sensing -- the putative explanatory gap -- is veridical or is merely a product of our uninformed and inappropriate intuitions. We need to embed our thought experiments in our interpretations of the actual data and relevant scientific theories as much as possible, lest all we produce is a statement of our own ignorance.
10. Nevertheless, I do not claim that my sketch of the relevant data and theory will assuage all skeptical intuitions -- the theory is not complete, nor do we have all the data yet. I explicitly admit that we do not know exactly what it is about the semantic memory (SE) system that gives us consciousness. In effect, I admit that we do not understand what we should to rule out the sort of intuitive gap in understanding that so moves Levine (though I confess I don't feel this gap myself nor can I imagine philosophical zombies).
11. However, this admission gives very little to the skeptics. I say we do not have a completed theory of consciousness and so do not understand the phenomenon in all its glory yet. From this it does not follow, so far as I can see, that skepticism about the project is warranted or that we should put much weight, if any at all, on our gapped feelings. The only way to proceed is to do more science. If, after much more research and scientific investigation, we still do not understand consciousness any more than we did before, then I will grudgingly admit defeat and acquiesce to the skeptics. But until then, I cannot see why we should be persuaded by their intuitions. Indeed, given that Levine himself admits that I "[marshal] an impressive array of empirical evidence ... in support of [my] thesis" that "consciousness should be identified with activation of the semantic memory (SE) system" (para. 1), I feel all the more confident that I am on the right track. We already know a lot more about consciousness than we did before scientists started investigating perception, memory, and cognition.
12. We can see better what I am trying to say if we examine Levine's desire to explain the simplest form of conscious experience, some very basic and primitive quale. He writes: "To me it makes perfect sense for there to be a mind that has just one state constantly, one qualitatively quite similar to mine if I were to stare at a wall of pure saturated red and think of nothing else" (para. 10). To him, qualia are not "conceptually tied to 'vividness' or representational richness at all" (para. 10). The question is: how seriously should we take the fact that a mono-quale mind is conceivable-to-Levine? If he is right that having such a mind makes perfect sense, then I can somewhat understand why he might be mystified by my discussing the richness of semantic content and the nature of information connectedness. (I say "somewhat" because I am interested in a theory of human consciousness, which obviously is quite rich, so I am uncertain whether any theory of human mentality should be applicable to the creature Levine has in mind.) But, whatever connection there is between complexity and consciousness will be discovered empirically and not through "a priori" reasoning. Suppose I am right, and consciousness is identified with the SE memory system and depends on (the possibility of) rich semantic connections; as a result, mono-quale minds turn out to be conceptually confused. In this case, it isn't clear whether we would still want to maintain that Levine's fantasy makes any sense, any more than we would want to say that it makes sense to imagine H2O as being something other than water. His vision would be empirically, and conceptually, off-base and the fact that he thinks he can entertain it should cut no ice with either theoreticians or philosophers.
13. What Levine -- and many other philosophers -- would like to have are qualia independent of any cognitive economy. However, wanting that might be like wanting water without H2O. It might sound good to the uninformed, but once you learn some things about consciousness, or water, you realize that such desires are misplaced. My view is that those people who believe that they can imagine conscious experience divorced from its role are either confused or are not imagining what they think they are.
Hardcastle, V.G. (1995). Locating Consciousness. Amsterdam & Philadelphia: John Benjamins Press.
Hardcastle, V.G. (1996a). The Why of Consciousness: A Non-Issue for Materialists. Journal of Consciousness Studies, 3: 7-13.
Hardcastle, V.G. (1996b). Precis of: Locating Consciousness. PSYCOLOQUY 7(33) locating.consciousness.1.hardcastle.
Levine, J. (1997). Consciousness Located: You'll Wonder Where the Yellow Went. PSYCOLOQUY 8(04) locating.consciousness.3.levine.