Does physicalism, as a philosophy of mind, require belief in a matter as substance upholding appearances?

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It took a little while for me to figure out what physicalism actually was, through the Wikipedia page. The whole thing rests on the idea of “supervenience.”

Supervenience, is a very intuitive concept to grasp intellectually, but really difficult to formally specify.

Being that physicalism is an evolution of materialism, let’s examine this new idea. The idea that everything supervenes on the physical is a really intuitively attractive one. Here is a diagram of supervenience:

My first question for the philosophers is, what do the rules underlying the supervenience themselves supervene on? It’s relatively easy to ignore the ‘lower’ levels, you can easily just say that physics itself is the supervening mechanism between atoms and elementary particles.

But look towards the top. You can’t call the basis for social groups supervening on living things physics. And even if you did, at some point you’d have to stop or it will get thoroughly absurd. Political entities supervene on social groups, this almost certainly can’t be physical. This is where defining “physical” becomes really important to your philosophy goal.

If you try to cop out by just pointing to the lower layers and saying “but since political entities supervene on social groups which supervene on living things which supervene on cells, everything still supervenes on the physical!” It’s a copout. Not all rules are physical. Towards the end of the definition part of the physicalism page, an ‘negative’ argument is made, defining the physical as “that which is not mental.”

So then the definition of supervenience is “A property A is said to supervene on a property B if any change in A necessarily implies a change in B.” This, applying physical rules, becomes less and less true as you get more and more abstract. Changing cells in one person’s body does not imply any sort of change in a social group, except in the most naive sense you can think of.

If you want to maintain a solid hierarchy, then you can’t supervene social groupings on top of ‘living things’, you have to introduce more descriptive, yet still abstract kinds of rules. Social groups convene for a reason, and if you change those reasons, then you’re effecting a sea change in the social group. So you have to supervene a social group on top of “reasons they need to work together.” Such as survival. When survival is no longer threatened, the social group will change. Sure, you could still supervene survival on physical things, and indeed, you can probably draw elaborate hierarchies that undergird everything with nice, comforting physicality, but you can’t really do that with everything. Not if you want to be intellectually rigorous.

So what physicalism in the sense of everything supervening on the physical becomes is throwing out the explanative nature of abstractions, in order to satisfy the desire to excise human imperfection. (physical being that which isn’t mental)