Yes, indeed, time does flee when you are fighting the living dead!
It has been a year since the original zombies wars broke out around here, which led to all of the zoombie and shombie action. I was recently looking over some of these old posts and the debate between Richard Chappell and myself as I get ready to do the re-write for the Journal of Consciousness Studies (where this paper and others from Consciousness Online are slated to appear).
The basic claim that Chappell makes is that the zoombie argument is not really a parody of the zombie argument. The basic reason for this is his claim that there is an important dis-analogy between the zombie argument and the zoombie argument. This dis-analogy arises because the completed micro-physical description of the world contains qualitative facts, if it does at all, only implicitly. This opens up the conceptual gap between the physical and the qualitative in a way that leaves the physicalist susceptible to the conceivability argument.
The dualist on the other had think that the qualitative facts are primitive and must be added to a completed micro-physics explicitly. Since the qualitative is not reducible to any base facts that are not themselves qualitative the dualist is not susceptible to conceivability arguments in the same way that the physicalist is. Another way to make the point, and a way that I think Richard prefers to make the point, is in terms of asking what follows from a completed micro-physics. The original zombie argument tries to show that the qualitative facts do not follow from the complete physical facts. The zoombie argument doesn’t work this way. We do no build up the non-physical facts and then ask whether or not the qualitative facts follow from them. This is because the dualist claims that the qualitative facts have to added explicitly. There is no issue of whether the follow from any other kind of fact since they are taken to be primitive.
Now, clearly, there is this dis-analogy between the two arguments. But does it follow, as Chappell alleged, that this dis-analogy makes it “daft” to mount a conceivability argument against the dualist? Or, another charge from Chappell, does this dis-analogy make the zoombie argument a bad parody of the original zombie argument (actually he said that it was irrational to think so, but let’s not dredge that stuff up) or show that I have misunderstood the original zombie argument (yet a further gem from Chappell)?
To start with the first question, the answer is obviously ‘no’. A conceivability argument just starts from the claim that something is conceivable and reasons to that thing’s being possible. If something follows from that possibility then fine.If not fine. In this case it is conceivable that NP, being the complete set of non-physical facts about the actual world, obtain without any qualitative properties included in NP. If this is conceivable then it is possible and if it is possible dualism is false. Is this a bad parody of the zombie argument? Only if you think a parody must be identical in every respect to the original. The point is that zoombie argument is like the zombie argument in the right respects; in particular in asserting the conceivability of p and reasoning from there. The fact that what is at issue in the zoombie argument is not “what follows from what” but is rather “what must be included in the complete non-physical description of a world that is non-physically identical to the actual world?” is irrelevant. All that maters is that the possibility of zoombies shows that qualitative properties are not non-physical properties. Finally, does this show that the proponent of the zoombie argument misunderstands the zombie argument? I don’t think so. The zombie proponent holds that zombies are conceivable because there is a gap between our physical/functional concepts and our qualitative concepts; or in other words that there is no reason as of now to think that qualitative properties are physical properties. The physicalist like me will claim that this gap will be abolished as we reach the ideal limit and so zombies are prima facie conceivable but not ideally conceivable. The zoombie proponent holds that zoombies are conceivable because there is no reason to think that qualitative properties are non-physical and so no reason to think that they must be included in a complete description of a non-physical duplicate of our world. Clearly both of these (zombies and zoombies) can’t be ideally conceivable so a priori arguments won’t help us decide between theories of consciousness.