Yeah, you are right. It is Physicalism.
We can take (a variant of) the zombie argument to check the weirdness of physicalism. Zombie argument is a very good argument. It requires two assumptions:
1.That what happens in human bodies is fully reducible to physical – It is just physical stuff behaving according to the physical laws.
2.That you allow that there is no metaphysical necessity that ‘given such and such configuration/dynamics of the physical stuff as it is in bodies of conscious people, consciousness will appear’. Or, alternatively that there is no metaphysical necessity that ‘given such and such configuration/dynamics of the physical stuff as it is in bodies of conscious people, there will be conscious experience such as it is in those people, and not different’.
The zombie argument then simply states that given we accept that there is no metaphysical necessity, it follows that it is a further fact about the world that with those configurations/dynamics there is related conscious experience (and exactly that conscious experience, and not some other). So, physicalism (the view that all facts are physical facts, or reducible to physical facts) is wrong.
So, let’s return to the premises of the argument…
Think about the term ‘no metaphysical necessity’. If I’m arguing that it is metaphysically possible that p, and you argue against me, you are arguing that it is metaphysically necessary that not p. So, for you not to accept the premise 2 of the zombie argument, is to say that it is metaphysically necessary that given such and such configuration/dynamics of the physical stuff as the one in the bodies of the conscious people, conscious experience will appear, and at that it is metaphysically necessary that this experience is as it is.
What this ‘metaphysically necessary’ means is that the alternative is contradiction. So, not just that the alternative is not possible in this world given the physical laws, but that it is straightforward contradiction. Like contradictions that we get in logic or math.
Now when we say “physical stuff” we mean something by it. It might not be very clear and distinct idea, but we have some kind of idea there that includes some things and doesn’t include others. For example it includes atoms, and doesn’t include soul.
Take for example the common idea of this “physical stuff”, which I take it to be this – there are elementary particles in the world, whose behavior is governed by physical laws (or one law). Because of those laws, particles form different configurations in which different dynamic patterns emerge on macro-level.
So, when a physicalist is opposing premise 2 of the zombie argument, he is arguing that given certain configuration/dynamics it follows (logically, mathematically, conceptually or in general metaphysically) that there will be conscious experience. So, not just that it so happens in this world that it must be so, like so it happens that the moon must obey the law of gravity, or that so it happens that two electrons must repel each other. But that it follows. Like in mathematical theorems. Like… we don’t need psychology, or first person reports – given sufficient knowledge and intelligence we can deduce what people experience. DEDUCE, like in A PRIORI (those words make most physicalists shudder, and yet there they are committed to possibility of deducing those weird things).
So, not sure if you are seeing the weirdness of this idea – to deduce the redness of the rose from the configuration/dynamics of the elementary particles in the world. Imagine how you approach math problems, and how some truths follow from another truths. Now imagine, how you start from certain configuration/dynamics of elementary particles, and deduce the redness of the rose. Like… you’ve been blind all your life, but they tell you everything about elementary particles, and the dynamic patterns in the brain of some person that is watching a rose, and you go to wherever you go to prove things, and after few days deduce the experience of redness of the rose. See, the problem? If you are to deduce something from X… say some Y, the notion Y has to be at least somewhat compatible with the notion X. New notions won’t magically appear in the proof. Physicalists are in that similar to (I guess caricature of) Pythagoreans which thought that they can deduce the world from numbers.
So, what can physicalist do about it? Maybe we were wrong to identify the idea of “physical stuff” with elementary particles governed by physical laws? Or maybe physicalists can claim a posteriori necessity? And if I think that zombie argument is good, and I also think that its conclusion (epiphenomenalism) is bad… what gives? Stay tuned!