Thus, if physicalism is true, a logically-possible world in which all physical facts are the same as those of the actual world must contain everything that exists in our actual world. In particular, conscious experience must exist in such a possible world.
In fact we can conceive of a world physically indistinguishable from our world but in which there is no consciousness (a zombie world). From this (so Chalmers argues) it follows that such a world is logically possible.
These two steps are contradictory. In the first one, you state that a world physically indistinguishable from ours must include consciousness; then in the very next point, you consider a world physically indistinguishable from ours which does not include consciousness to be logically possible—exactly what the previous step claims is not logically possible.
So the second is then implicitly assuming that physicalism is not true; it seems to me that the whole argument is basically a longwinded way of saying “I can’t imagine how consciousness can possibly be physical, therefore since I am conscious, physicalism is false”.
One might as easily imagine a world physically indistinguishable from ours, but in which there is no gravity, and thence conclude that gravity is not physical but somehow magical.
For some values of “imagine”. Given relativity, it would be pretty difficult to coheretly unplug gravity from mass, space and acceleration. It would be easier under Newton. I conclude that the unpluggabiliy of qualia means we just don’t have a relativity-grade eplanation of them, an explanation that makes them deeply interwoven with other things.
I conclude that the unpluggabiliy of qualia means we just don’t have a relativity-grade eplanation of them, an explanation that makes them deeply interwoven with other things.
Inertia and mass are the same thing. You probably meant “the same proportionality constant between mass and gravitational force”, that is, imagine that the value of Newton’s constant G was different.
But this (like CCC’s grandparent post introducing the gravity analogy) actually goes in Chalmers’ favor. Insofar as we can coherently imagine a different value of G with all non-gravitational facts kept fixed, the actual value of G is a new “brute fact” about the universe that we cannot reduce to non-gravitational facts. The same goes for consciousness with respect to all physical facts, according to Chalmers. He explicitly compares consciousness to fundamental physical quantities like mass and electric charge.
The problem is that one aspect of the universe being conceptually irreducible at the moment (which is all that such thought experiments prove) does not imply it might forever remain so when fundamental theory changes, as Peterdjones says. Newton could imagine inertia without gravity at all, but after Einstein we can’t. Now we are able to imagine a different value of G, but maybe later we won’t (and I can actually sketch a plausible story of how this might come to happen if anyone is interested).
No, I meant a form of matter which coexisted with current forms of matter but which was accelerated by a force disproportionately to the amount of force exerted through the gravity force. One such possibility would be something that is ‘massless’ in that it isn’t accelerated by gravity but that has electric charge.
And by definition, the value of G is equal to 1, just like every other proportionality constant. I wasn’t postulating that MG/NS^2 have a different value.
One might as easily imagine a world physically indistinguishable from ours, but in which there is no gravity, and thence conclude that gravity is not physical but somehow magical.
Oooh, good one. I’m trying this if someone ever seriously tries to argue p-zombies with me.
These two steps are contradictory. In the first one, you state that a world physically indistinguishable from ours must include consciousness; then in the very next point, you consider a world physically indistinguishable from ours which does not include consciousness to be logically possible—exactly what the previous step claims is not logically possible.
Or am I misunderstanding something?
The first includes “if physicalism is true”, the second doens’t.
Ah, right. Thanks, I somehow missed that.
So the second is then implicitly assuming that physicalism is not true; it seems to me that the whole argument is basically a longwinded way of saying “I can’t imagine how consciousness can possibly be physical, therefore since I am conscious, physicalism is false”.
One might as easily imagine a world physically indistinguishable from ours, but in which there is no gravity, and thence conclude that gravity is not physical but somehow magical.
For some values of “imagine”. Given relativity, it would be pretty difficult to coheretly unplug gravity from mass, space and acceleration. It would be easier under Newton. I conclude that the unpluggabiliy of qualia means we just don’t have a relativity-grade eplanation of them, an explanation that makes them deeply interwoven with other things.
That seems like a reasonable conclusion to draw.
Not really. Just postulate something which does not have the same proportionality constant relating inertia to mass.
Inertia and mass are the same thing. You probably meant “the same proportionality constant between mass and gravitational force”, that is, imagine that the value of Newton’s constant G was different.
But this (like CCC’s grandparent post introducing the gravity analogy) actually goes in Chalmers’ favor. Insofar as we can coherently imagine a different value of G with all non-gravitational facts kept fixed, the actual value of G is a new “brute fact” about the universe that we cannot reduce to non-gravitational facts. The same goes for consciousness with respect to all physical facts, according to Chalmers. He explicitly compares consciousness to fundamental physical quantities like mass and electric charge.
The problem is that one aspect of the universe being conceptually irreducible at the moment (which is all that such thought experiments prove) does not imply it might forever remain so when fundamental theory changes, as Peterdjones says. Newton could imagine inertia without gravity at all, but after Einstein we can’t. Now we are able to imagine a different value of G, but maybe later we won’t (and I can actually sketch a plausible story of how this might come to happen if anyone is interested).
No, I meant a form of matter which coexisted with current forms of matter but which was accelerated by a force disproportionately to the amount of force exerted through the gravity force. One such possibility would be something that is ‘massless’ in that it isn’t accelerated by gravity but that has electric charge.
And by definition, the value of G is equal to 1, just like every other proportionality constant. I wasn’t postulating that MG/NS^2 have a different value.
Oooh, good one. I’m trying this if someone ever seriously tries to argue p-zombies with me.
Most versions of the Zombie Argument I’ve seen don’t specify that the world be physically identical to ours, merely indistinguishable.
http://en.wikipedia.org/wiki/Proof_by_contradiction