I think that main problem of this (and similar) reasoning is its circularity. This circularity doesn’t make such reasoning untrue, but weakens its evidence base.
It starts with (some version of) physicalism is true. And its conclusion is that there is nothing that is not physical.
If we take definition (one of) of the physicalism from SEP:
It means that by definition a copy has all the same qualities (including consciousness and qualia) as original.
We could see that zombies are impossible in physical world by definition of physical world.
So there is no need to prove anything.
So the only thing we need to do in order to disprove zombies—is to prove that physicalism is true. So we could go to the end of SEP article and check what kind of proves exist.
There are two:
1) Idea of casual closure of all world
2) Knowledge from science about physics and idea that philosophy should be similar to the most successful scientific explanation of the world
Both of them have some problems, some of them: What is causality? Or if we find ourself in the world which will be describe in the best possible form by existence of many small gods, should we take it as prove of their metaphysical nature?
Basically first 50 pages of SEP article is about problems with physicalism and I was surprised that there are so many of them.
These ideas penetrates in typical discussions about consciousness in subtle form. Someone starts with: “ok we know, that all out thoughts consists of atoms, neurons etc, so there is no place for qualia etc”. So he used latest knowledge from science to prove his point, that is using (2). But science knowledge about where and how we have experiences are incomplete, and he also implicitly use science as a prove to physicalism
I think that we need new definition and new prove of physicalism, and in this case we will be able to solve all its puzzles.
I think that main problem of this (and similar) reasoning is its circularity. This circularity doesn’t make such reasoning untrue, but weakens its evidence base.
It starts with (some version of) physicalism is true. And its conclusion is that there is nothing that is not physical.
If we take definition (one of) of the physicalism from SEP:
“(1) Physicalism is true at a possible world w iff any world which is a physical duplicate of w is a duplicate of w simpliciter.” http://plato.stanford.edu/entries/physicalism/#NonModDefPhy
It means that by definition a copy has all the same qualities (including consciousness and qualia) as original.
We could see that zombies are impossible in physical world by definition of physical world.
So there is no need to prove anything.
So the only thing we need to do in order to disprove zombies—is to prove that physicalism is true. So we could go to the end of SEP article and check what kind of proves exist.
There are two:
1) Idea of casual closure of all world
2) Knowledge from science about physics and idea that philosophy should be similar to the most successful scientific explanation of the world
Both of them have some problems, some of them: What is causality? Or if we find ourself in the world which will be describe in the best possible form by existence of many small gods, should we take it as prove of their metaphysical nature?
Basically first 50 pages of SEP article is about problems with physicalism and I was surprised that there are so many of them.
These ideas penetrates in typical discussions about consciousness in subtle form. Someone starts with: “ok we know, that all out thoughts consists of atoms, neurons etc, so there is no place for qualia etc”. So he used latest knowledge from science to prove his point, that is using (2). But science knowledge about where and how we have experiences are incomplete, and he also implicitly use science as a prove to physicalism
I think that we need new definition and new prove of physicalism, and in this case we will be able to solve all its puzzles.