She begins by thinking about zombies and the things they say. If there really is a world that is microphysically identical to ours but that lacks consciousness and one of those creatures is a microphysical duplicate of David Chalmers then it is reasonable to think that Zombie-Dave will be giving zombie versions of the zombie argument. Zombie-Dave will say things like that he doesn’t see how structure and function could suffice for phenomenal experience even though all the while he doesn’t have any phenomenal experience (he is a zombie after all). Zombie-Dave will even say things like from the fact that he can conceive of all of the physical facts without the phenomenal facts obtaining it follows that physicalism is false.
The response to this argument hinges on the distinction between negative and positive conceivability. To negatively conceive of something is simply to be unable to rule it out a priori. Positive conceivability involves something more. For Kati positive conceivability is just negative conceivability (i.e. not being able to rule something out a priori) plus the application of standard everyday concepts. This is a modest notion of positive conceivability that leaves no room for an act of the imagination or a special act of conceiving. At any rate, the response to the Zombie-Dave objection then becomes the claim that while Zombie-Dave might be able to negatively conceive of P & ~Q* (where Q* is Zombie-Dave’s conception of what a phenomenal property is) he cannot positively conceive of it.
One of the interesting things that came up at this point was whether or not zombie phenomenal concepts have any mode of presentation. Kati seemed to think that they did not. Since Zombie-Dave denies that phenomenal properties are physical/functional properties it seems right to say that the zombie phenomenal concepts do not present phenomenal properties as physical/functional properties. Given that zombies actually lack phenomenal properties then there doesn’t seem to be anything else that could be a mode of presentation. So Kati thinks that a zombie’s phenomenal concept refers to a physical state of the zombie’s brain but it doesn’t present that property to the zombie in any way. While this seems right, it also seems right to say that there is some way in which the zombie thinks about, discriminates, or is rationally responsive to things it would call red, blue, green, etc. If all one means by mode of presentation is something like ‘a way of thinking about the referent’ then there doesn’t seem to be any problem in saying that the zombie’s phenomenal concepts present the brain states in a certain way.
Kati then introduces Illuminati as an answer to the positive conceivability argument. Illuminati are creatures that are completely and only physical and which have phenomenal properties. I call illuminati ‘shombies’ Keith Frankish has called them ‘anti-zombies’. Are such creatures conceivable? Well, clearly they are at least negatively conceivable. As Kati argued, illuminati are negatively conceivable for the same reason that zombies are. There is nothing in our grasp of phenomenal properties that tells us one way or the other whether they are physical or not. This is an important point. Someone who denies this is what I call a type-A dualist. Type-A dualism seems to me to be clearly an unattractive view since it amount to no more than defining phenomenal properties into nonphysicality. The response to this negative conceivability argument is again to invoke positive conceivability and the a priority of the zombie intuition. if it is a priori that zombies are positively conceivable then it cannot be the case that illuminati are negatively conceivable.
At this point there are two ways one can go. Kati’s preferred way is to try and bolster the negative conceivability of illuminati by offering a coherent physicalist metaphysics and ontology. If one can give a coherent philosophical account in completely physicalist terms then it would seem to bolster the case for the negative conceivability of illuminati. Another way to go would be to invoke positive conceivability of shombies. The shombie argument starts from the premise that shombies are positively conceivable (or what I really think is that it starts from the premise that they seem positively conceivable). Kati is skeptical of this move since she thinks that someone like Dave might be working with a notion of positive conceivability that is strong enough to make shombies inconceivable. My feeling is that any such notion will also make zombies inconceivable. But we would have to see the actual account of positive conceivability in play. According to the one I have been working with, shombies certainly seem positively conceivable. I can actually imagine discovering that we are shombies via the use of a philosophical theory of consciousness (like a higher-order theory) and relevant brain science discoveries.
Dave’s objection was that zombies are more intuitively conceivable than shombies. Perhaps after the acquisition of a bunch of theory one could have the shombie intuition but regular people have the zombie intuition quite strongly and pre-theoretically. I wonder whether if some experimental philosopher actually asked a bunch of undergraduates whether Dave would be right. My experience is that at least some of my students have the shombie intuition quite strongly and seemingly pre-theoretically. But I really don’t see why this matters. That one theory is taken for granted doesn’t show that it is true. I can’t imagine that someone who objected to the heliocentric view of the universe by complaining that one needed a bunch of advanced physics under your belt to see how it could be true would be taken seriously. It might be true that our natural inclinations run towards dualism; I admit that mine did when I was an undergraduate…but I also thought that the structure of the atom mirrored the structure of the solar system.
So I think that the shombie argument is the natural next move in the debate, but Kati does not. She then wonders what we are to say if at the end of the day we end up with two theories that are mutually incompatible but equally simple, elegant, predictive, and supported by the empirical evidence? If the physicalist and the dualist are each able to offer complete metaphysical and epistemological frameworks that are both compatible with the totality of the findings from science then what are we to say? Do we say that there is a fact of the matter about which theory is correct? Or do we say that there is no determinate fact of the matter about which is true? Or finally do we say that the issue is merely terminological? Kati seems to think that the answer is indeterminate. I think it is probably just terminological at that point, though as I have been arguing recently, I wonder if the dualist can even give a coherent account of what nonphysical properties are and so I doubt that we will end up with two equal theories at the end of inquiry. It seems to me that if the debate between the dualist and the physicalist comes out to be indeterminate then there are no determinate facts at all. That is, once we go Quinian we can’t stop the backslide all way to the inscrutability of reference. I for one just can’t bring myself to believe this. I mean if it were true then the fact that there are no determinate facts is itself indeterminate; but what could that mean?
…or so it seems to me at first glance as I run out of the house to class…