Eliezer—thanks for this post, it’s certainly an improvement on some of the previous ones. A quick bibliographical note: Chalmers’ website offers his latest papers, and so is a much better source than google books. A terminological note (to avoid unnecessary confusion): what you call ‘conceivable’, others of us would merely call “apparently conceivable”. That is, you view would be characterized as a form of Type-A materialism, the view that zombies are not even (genuinely) conceivable, let alone metaphysically possible. On to the substantive points:
(1) You haven’t, so far as I can tell, identified any logical contradiction in the description of the zombie world. You’ve just pointed out that it’s kind of strange. But there are many bizarre possible worlds out there. That’s no reason to posit an implicit contradiction. So it’s still completely mysterious to me what this alleged contradiction is supposed to be.
(2) It’s misleading to say it’s “miraculous” (on the property dualist view) that our qualia line up so neatly with the physical world. There’s a natural law which guarantees this, after all. So it’s no more miraculous than any other logically contingent nomic necessity (e.g. the constants in our physical laws). That is, it’s “miraculous” in the same sense that it’s “miraculous” that our universe is fit to support life. Atheists and other opponents of fine-tuning arguments are not usually so troubled by this kind of alleged ‘miracle’. Just because things logically could have been different, doesn’t mean that they easily could have been different. Natural laws are pretty safe and dependable things. They are primitive facts, not explained by anything else, but that doesn’t make them chancy.
(3) I’d also dispute the following characterization: “talk about consciousness… arises from a malfunction (drawing of logically unwarranted conclusions) in the causally closed cognitive system that types philosophy papers.”
No, typing the letters ‘c-o-n-s-c-i-o-u-s-n-e-s-s’ arises from a causally closed cognitive system. Whether these letters actually mean anything (and so constitute a contentful conclusion that may or may not follow from other contentful premises) arguably depends on whether the agent is conscious. (Utterances express beliefs, and beliefs are partly constituted by the phenomenal properties instantiated by their neural underpinnings.) That is, Zombie (or ‘Outer’) Chalmers doesn’t actually conclude anything, because his utterances are meaningless. A fortiori, he doesn’t conclude anything unwarrantedly. He’s just making noises; these are no more susceptible to epistemic assessment than the chirps of a bird. (You can predict the zombie’s behaviour by adopting the Dennettian pretense of the ‘intentional stance’, i.e. interpreting the zombie as if it really had beliefs and desires. But that’s mere pretense.)
(4) I’m all for ‘reflective coherence’ (at least if that means what I think it means). I don’t see how it counts against this view, unless you illicitly assume a causal theory of knowledge (which I obviously don’t).
P.S. Note that while I’m a fan of epiphenomenalism myself, Chalmers doesn’t actually commit to the view. See his response to Perry for more detail. (It also addresses many of the other points you raise in this post.)
On (3), if Zombie Chalmers can’t be correct or incorrect about consciousness—as in, he’s just making noise when he says “consciousness”—does the same hold for his beliefs on anything else? Like, Zombie Chalmers also (probably) says “the sun will rise tomorrow,” but would you also question whether these letters actually mean anything? In both the cases of the sun’s rising and epiphenomenalism’s truth, Zombie Chalmers is commenting on an actual way that reality can be. Is there a difference? Or, does Zombie Chalmers have no beliefs about anything? I’d think that a zombie could be thought to have beliefs as far as some advanced AI could.
That misses the point. No one can possibly show any logical contradiction in the hypothesis that zombies exist, because those who postulate it have not made their claim falsifiable. As in, there is no observable difference between a world with zombies versus one without them. Similarly, I could claim my room is filled with scientifically undetectable, invisible fairies and you would not be able to logically refute this claim. I don’t believe your inability to disprove it would make it any less laughable, however. The fact that the hypothesis is unfalsifiable says something about Chalmer, not about Eliezer.
To be honest, I wonder why a philosopher would go on those lengths to argue for something that has no impact on the world whatsoever.
Eliezer—thanks for this post, it’s certainly an improvement on some of the previous ones. A quick bibliographical note: Chalmers’ website offers his latest papers, and so is a much better source than google books. A terminological note (to avoid unnecessary confusion): what you call ‘conceivable’, others of us would merely call “apparently conceivable”. That is, you view would be characterized as a form of Type-A materialism, the view that zombies are not even (genuinely) conceivable, let alone metaphysically possible. On to the substantive points:
(1) You haven’t, so far as I can tell, identified any logical contradiction in the description of the zombie world. You’ve just pointed out that it’s kind of strange. But there are many bizarre possible worlds out there. That’s no reason to posit an implicit contradiction. So it’s still completely mysterious to me what this alleged contradiction is supposed to be.
(2) It’s misleading to say it’s “miraculous” (on the property dualist view) that our qualia line up so neatly with the physical world. There’s a natural law which guarantees this, after all. So it’s no more miraculous than any other logically contingent nomic necessity (e.g. the constants in our physical laws). That is, it’s “miraculous” in the same sense that it’s “miraculous” that our universe is fit to support life. Atheists and other opponents of fine-tuning arguments are not usually so troubled by this kind of alleged ‘miracle’. Just because things logically could have been different, doesn’t mean that they easily could have been different. Natural laws are pretty safe and dependable things. They are primitive facts, not explained by anything else, but that doesn’t make them chancy.
(3) I’d also dispute the following characterization: “talk about consciousness… arises from a malfunction (drawing of logically unwarranted conclusions) in the causally closed cognitive system that types philosophy papers.”
No, typing the letters ‘c-o-n-s-c-i-o-u-s-n-e-s-s’ arises from a causally closed cognitive system. Whether these letters actually mean anything (and so constitute a contentful conclusion that may or may not follow from other contentful premises) arguably depends on whether the agent is conscious. (Utterances express beliefs, and beliefs are partly constituted by the phenomenal properties instantiated by their neural underpinnings.) That is, Zombie (or ‘Outer’) Chalmers doesn’t actually conclude anything, because his utterances are meaningless. A fortiori, he doesn’t conclude anything unwarrantedly. He’s just making noises; these are no more susceptible to epistemic assessment than the chirps of a bird. (You can predict the zombie’s behaviour by adopting the Dennettian pretense of the ‘intentional stance’, i.e. interpreting the zombie as if it really had beliefs and desires. But that’s mere pretense.)
(4) I’m all for ‘reflective coherence’ (at least if that means what I think it means). I don’t see how it counts against this view, unless you illicitly assume a causal theory of knowledge (which I obviously don’t).
P.S. Note that while I’m a fan of epiphenomenalism myself, Chalmers doesn’t actually commit to the view. See his response to Perry for more detail. (It also addresses many of the other points you raise in this post.)
On (3), if Zombie Chalmers can’t be correct or incorrect about consciousness—as in, he’s just making noise when he says “consciousness”—does the same hold for his beliefs on anything else? Like, Zombie Chalmers also (probably) says “the sun will rise tomorrow,” but would you also question whether these letters actually mean anything? In both the cases of the sun’s rising and epiphenomenalism’s truth, Zombie Chalmers is commenting on an actual way that reality can be. Is there a difference? Or, does Zombie Chalmers have no beliefs about anything? I’d think that a zombie could be thought to have beliefs as far as some advanced AI could.
Replying to (1):
That misses the point. No one can possibly show any logical contradiction in the hypothesis that zombies exist, because those who postulate it have not made their claim falsifiable. As in, there is no observable difference between a world with zombies versus one without them. Similarly, I could claim my room is filled with scientifically undetectable, invisible fairies and you would not be able to logically refute this claim. I don’t believe your inability to disprove it would make it any less laughable, however. The fact that the hypothesis is unfalsifiable says something about Chalmer, not about Eliezer.
To be honest, I wonder why a philosopher would go on those lengths to argue for something that has no impact on the world whatsoever.