Those who do see philosophical zombies as possible don’t have a clear idea of how consciousness relates to the brain, but they do think...that consciousness is something more than just the functions of the brain. In their view, a digital person (an uploaded human mind which runs on software) may act like a conscious human, and even tell you all about its ‘conscious experience’, but it is possible that it is in fact empty of experience.
It’s consistent to think that p-zombies are possible but to think that, given the laws of nature, digital people would be conscious. David Chalmers is someone who argues for both views.
It might be useful to clarify that the questions of
(a) whether philosophical zombies are metaphysically possible (and the closely related question of physicalism about consciousness)
is actually somewhat orthogonal to the question of
(b) whether uploads that are functionally isomorphic to humans would be conscious
David Chalmers thinks that philosophical zombies are metaphysically possible, and that consciousness is not identical to the physical. But he also argues that, given the laws of nature in this world, uploaded minds, of sufficiently fine-grained functional equivalence to human minds, that act and talk like conscious humans would be conscious. In fact, he’s the originator of the ‘fading qualia’ argument that Holden appeals to in his post.
On the other side, Ned Block thinks that zombies are not possible, and is a physicalist. But he also thinks that only biological-instantiated minds can be conscious.
Here’s Chalmers (2010) on the distinction between the two issues:
I have occasionally encountered puzzlement that someone with my own property dualist views (or even that someone who thinks that there is a significant hard problem of consciousness) should be sympathetic to machine consciousness. But the question of whether the physical correlates of consciousness are biological or functional is largely orthogonal to the question of whether consciousness is identical to or distinct from its physical correlates. It is hard to see why the view that consciousness is restricted to creatures with our biology should be more in the spirit of property dualism! In any case, much of what follows is neutral on questions about materialism and dualism.
You write,
It’s consistent to think that p-zombies are possible but to think that, given the laws of nature, digital people would be conscious. David Chalmers is someone who argues for both views.
It might be useful to clarify that the questions of
(a) whether philosophical zombies are metaphysically possible (and the closely related question of physicalism about consciousness)
is actually somewhat orthogonal to the question of
(b) whether uploads that are functionally isomorphic to humans would be conscious
David Chalmers thinks that philosophical zombies are metaphysically possible, and that consciousness is not identical to the physical. But he also argues that, given the laws of nature in this world, uploaded minds, of sufficiently fine-grained functional equivalence to human minds, that act and talk like conscious humans would be conscious. In fact, he’s the originator of the ‘fading qualia’ argument that Holden appeals to in his post.
On the other side, Ned Block thinks that zombies are not possible, and is a physicalist. But he also thinks that only biological-instantiated minds can be conscious.
Here’s Chalmers (2010) on the distinction between the two issues: