Chalmers and sceptical threats
Hi Folks, the following question came up in teaching recently, and I was wondering if anyone can help.
As is well known, Chalmers claims that experience does not logically supervene on functional organisation (the zombie argument). He also claims that experience does supervene, nomologically, on functional organisation (the dancing qualia argument). In other words, if the natural laws (including the dualist’s psychophysical laws) are kept fixed, then experience supervenes on functional organisation.
Here is the central motivation for this nomological supervenience claim:
It is a central fact about experience, very familiar from our own case, that whenever experiences change significantly and we are paying attention, we can notice the change; if this were not to be the case, we would be led to the skeptical possibility that our experiences are dancing before our eyes all the time. This hypothesis has the same status as the possibility that the world was created five minutes ago: perhaps it is logically coherent, but it is not plausible. Given the extremely plausible assumption that changes in experience correspond to changes in processing, we are led to the conclusion that the original hypothesis is impossible, and that any two functionally isomorphic systems must have the same sort of experiences. To put it in technical terms, the philosophical hypotheses of “absent qualia” and “inverted qualia”, while logically possible, are empirically and nomologically impossible. (from “Facing up the problem of consciousness”)
The idea being that if experience were not to (nomologically) supervene on functional organisation, we would be faced with a sceptical threat: our experience could change all the time, and we would not notice it (in the information-processing, reporting, sense of noticing).
But if this sceptical concern moves you, then why doesn’t it also undermine the zombie argument?
For all we know, the psychophysical laws could be changing all the time. They could be changing so as to make the (logically possible) zombie world the actual world, or a (logically possible) world in which our experience is inverted the actual world. As far as the information-processing aspects of our life is concerned, we would not notice the difference. By hypothesis, the functional (information-processing, reporting, etc.) properties of our mental life would be the same in both scenarios. Aren’t we faced here with the same kind of sceptical threat about knowledge of our experience?
If one wants to use the sceptical threat to motivate supervenience of experience on functional organisation in the nomological case, why doesn’t this have equal force in the logical (zombie) case too? Alternatively, if one discounts this sceptical threat as carrying any weight in the zombie case, then why does it have force in the nomological case?
I remember Chalmers talks about knowledge of experience in the ‘Paradox of phenomenal judgement’. But I seem to remember that the upshot was that knowledge of experience should not be understood on the model of a causal theory of knowledge. But if that is the case, and for example we have some sort of direct knowledge of experience, wouldn’t this undermine the sceptical threat in the dancing qualia argument?
Any help gratefully received.