Keith Frankish, posting on the Splintered Mind, summarizes very interesting Anti-Zombie Argument as follows:
Consider anti-zombies. These are beings that are physical duplicates of humans, and that have no non-physical properties, but which are nonetheless conscious. They inhabit an anti-zombie world, which is a physical duplicate of ours, but where no non-physical properties are instantiated. (Physicalists think that we are anti-zombies, of course.) Then we can run an anti-zombie argument for physicalism, as follows. Anti-zombies are conceivable and therefore, by the CP principle, metaphysically possible. And if anti-zombies are metaphysically possible, then physicalism is true. The last step may seem a big one, but it should be uncontroversial. In the anti-zombie world consciousness is physical, so the microphysical features of that world are metaphysically sufficient for consciousness, and any world with the same microphysical features will have the same distribution of phenomenal properties. But, by definition, our world has the same microphysical features as the anti-zombie world. Hence the microphysical features of our world are metaphysically sufficient for the existence of consciousness, which is to say that physicalism is true.
Here’s an excerpt of a response I left:
Consider a version of zombism that doesn’t seem touched by your argument. I don’t believe it, and I don’t know anyone who does, but it is worth considering.
On this version of zombism, consciousness is massively multiply realized. In some worlds—Berkeleyan ghost worlds—there are no physical properties, only consciousnesses. In those worlds, my mental doppleganger is realized by networks of non-physical ectoplasmic psychons, or spook-juice, or something. In other worlds—Cartesian fractured worlds—there exist both minds and bodies, and like the ghost worlds, conscious stuff is realized by non-physical spook-juice. In other worlds—anti-zombic worlds—consciousness is realized by solely physical stuff. In other worlds—zombic worlds–there’s all the same physical stuff as in the anti-zombic worlds, but absolutely no consciousness, perhaps because of different laws that operate there, or something.
So, I guess this imagined zombist would deny your statement that “any world with the same microphysical features will have the same distribution of phenomenal properties.”
I suppose you’ll need some reason why such a move wouldn’t be available to the zombist. What is it?