Hi Q,
Science doesn’t, and naturalism doesn’t (commit to the claim that one can a priori get from physical facts to the facts about consciousness). But that is THE commitment of physicalism. Physicalism is not equal to science. It is just yet another metaphysical position. Physicalist’s position is usually defined that metaphysically there is no difference without metaphysical difference. And the metaphysical necessity is a priori necessity. (Some try to say that physicalism doesn’t need to claim a priori necessity, but only Kripkean a posteriori necessity, but that is , seems to me, really just hiding the commitment of a priori deduction. I could say more on this, if needed).
So, when person presents zombie argument, he doesn’t give argument against science, nor physics, but against this metaphysical commitment of physicalism (defined as “no difference without physical difference). I wonder if lot of negative reactions to the zombie argument in this series of post is mixing up the naturalistic/scientific view on the world with the claims of physicalism. (Of course there is also the silly consequences of the epiphenomenalism, but as I said, we can take that as a reductio.)
This was very funny...
On more serious not, there is nothing wrong with zombie argument. It just says that physicalism claims that you can a priori deduce the facts about conscious experience (e.g. if there is conscious experience/exactly what kind of conscious experience there is) from the physical facts about the system. Notice that ‘a priori’. So, it is not just that we can come to know which physical facts are correlated with what facts about consciousness, or which physical phenomenon gives rise to consciousness, but that we can deduce like we deduce mathematical truths.
So, zombie argument just says, that given what our idea of physical system consist of now—i.e. the patterns of behavior of complex structures of elementary physical particles, governed by physical laws which take form of mathematical equations… you can’t deduce anything like facts about conscious experience. So, it says, there is no way, without the knowledge based on the science which would relate this behavior to our conscious experience, that one could go from the description expressed in mathematical equations which relate different measurables of the systems, like position, energy, momentum, etc..., and A PRIORI deduce facts, like if there is conscious experience, or the facts about what kind of conscious experience one has.
“But ‘physical’ is not just what we know about the world now, it means everything that will be approachable by physical science in future also!”
Well, that’s OK, but if those equations are still nothing but mathematical equations which show how different measurables relate, there is no way to start from THAT, and a priori deduce facts as e.g. there being conscious experience, or the facts about it. Again, it is not if we can scientifically know based on the physical facts if there is, or not conscious experience, and know again based on scientific research what kind of conscious experience there is.
It is about impossibility to deduce a priori this conscious experience, from descriptions which are in terms of concepts which are incommensurable with conscious experience. We might as well, try to deduce the mass of Earth solely from the Pythagorean Theorem.
“But… epiphenomenalism, the view that consciousness is epiphenomenon is silly”
Yes, it is. But that the zombie argument starts from some position taking some assumptions of physicalism and refusing others, and as a result has epiphenomenalism as conclusion, is nothing but reductio ad absurdum of those other assumptions which epiphenomenalism shares with physicalism.
Anyway… hope I don’t spoil everyone’s joy with the post, as it was pure comedy gold!