Complicating the Zombie dualist argument
Zombie philosophy is one of hte most interesting parts of philosophy to me. why? well it seems that there has been a lot of debate that has resulted in a sort of cold war, but in spite of that there are a number of lights at the end of the tunnel that threaten to do some serious harm to the dualist argument. The other key factor is the religious like confidence of both sides as they present their often dubious arguments - "something is very wrong on the internet".
Richard Brown presents us with, three thought experiments
First the players
Zombies are creatures that are identical to us in every physical respect but which lacks qualitative consciousness.
A Zoombie are creatures that is identical to us in every non-physical respect but which lacks qualitative consciousness.
Shombies are completely physical creatures who are identical to their real world twins in every mico-physical way. The difference between zombies and shombies is that shombies have qualitative consciousness.
now lets assume being able to concieve of something means it is possible.
now we can 'conceive' of a zombie so that seems to imply that consciousness is non physical - but we can also 'conceive' of a Zoombie - which implies conciousness is not non physical - or at least it cant be reduced to non physical facts that dont explicitly reference them. And now we can also 'conceive' of a Shombie - which means conciousness must be physical (because it is physical for a shombie).
anyway here is keith frankish on Erics blog - arguing for anti zombies
The point can be made independently by considering the unique world that is a physical duplicate of ours and where no further, non-physical properties are instantiated. This should be a zombie world, if any is. But it's also the only candidate for an anti-zombie world. Thus, the possibility of zombies is incompatible with that of anti-zombies. And if conceivability entails possibility, then the conceivability of zombies is incompatible with that of anti-zombies. So defenders of the zombie argument must deny that anti-zombies are conceivable.
Now of course physicalism is the view that we are anti-zombies, so if anti-zombies aren't conceivable then physicalism isn't conceivable either. In short, if you want to endorse the zombie argument, then you have to maintain that physicalism is inconceivable.
keith also puts forward another version
Incidentally, it is possible to run a metamodal version of the AZ argument, which by-passes the step just mentioned. It goes like this. Let P be the actual physical facts and Q the phenomenal ones. Then it is conceivable that P -> Q is necessary. If it is conceivable that P -> Q is necessary, then (by the CP thesis) it is possible that P -> Q is necessary. If it is possible that P -> Q is necessary, then P -> Q is necessary (S5 principle MLp -> Lp). If P -> Q is necessary, then consciousness is physical. Hence consciousness is physical. Peter Marton's version of the argument was along those lines.
In the comments interestingly
Richard Brown presents us with, three thought experiments
First the players
Zombies are creatures that are identical to us in every physical respect but which lacks qualitative consciousness.
A Zoombie are creatures that is identical to us in every non-physical respect but which lacks qualitative consciousness.
Shombies are completely physical creatures who are identical to their real world twins in every mico-physical way. The difference between zombies and shombies is that shombies have qualitative consciousness.
now lets assume being able to concieve of something means it is possible.
now we can 'conceive' of a zombie so that seems to imply that consciousness is non physical - but we can also 'conceive' of a Zoombie - which implies conciousness is not non physical - or at least it cant be reduced to non physical facts that dont explicitly reference them. And now we can also 'conceive' of a Shombie - which means conciousness must be physical (because it is physical for a shombie).
anyway here is keith frankish on Erics blog - arguing for anti zombies
The point can be made independently by considering the unique world that is a physical duplicate of ours and where no further, non-physical properties are instantiated. This should be a zombie world, if any is. But it's also the only candidate for an anti-zombie world. Thus, the possibility of zombies is incompatible with that of anti-zombies. And if conceivability entails possibility, then the conceivability of zombies is incompatible with that of anti-zombies. So defenders of the zombie argument must deny that anti-zombies are conceivable.
Now of course physicalism is the view that we are anti-zombies, so if anti-zombies aren't conceivable then physicalism isn't conceivable either. In short, if you want to endorse the zombie argument, then you have to maintain that physicalism is inconceivable.
keith also puts forward another version
Incidentally, it is possible to run a metamodal version of the AZ argument, which by-passes the step just mentioned. It goes like this. Let P be the actual physical facts and Q the phenomenal ones. Then it is conceivable that P -> Q is necessary. If it is conceivable that P -> Q is necessary, then (by the CP thesis) it is possible that P -> Q is necessary. If it is possible that P -> Q is necessary, then P -> Q is necessary (S5 principle MLp -> Lp). If P -> Q is necessary, then consciousness is physical. Hence consciousness is physical. Peter Marton's version of the argument was along those lines.
In the comments interestingly
I gave an argument similar to the anti-zombie argument in a paper presented at Tucson VII - Toward a Science of Consciousness 2006. One of my conclusions was, as you say, that a zombie-file must hold that physicalism is inconceivable. I had a conversation with Chalmers about it, and he confirmed that that's precisely his view.