The unexamined assumption of fundamentality in physicalism (re: Sean Carroll episode)

After listening to the latest episode with Sean Carrol I thought I will address something that is not being properly addressed often, namely that the physicalist privileges the level of atoms implying epistemic or even ontological priority, saying things like "well it is all just atoms of course" as if that is self evident. I will try to be precise so that people respond to specific points with the numbering.

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Many people believe that atoms are more "real" than cities let's say. Cities here stands for any macro level entity/unit of our world of the senses, from tree and table, to sport team, colour, justice etc. The standard argument goes something like this:

[1] Cities depend on atoms for their existence but atoms do not depend on cities.

From [1] we are meant to conclude that atoms are more fundamental, more basic, more real. But I think this reasoning has gaps.

Consider the full chain: you have atoms, then bricks, then a house, and inside the house there is a family with a whole history. They are developing things, and one of them becomes a scientist, and that scientist discovers atoms.

Why does it make any sense to say that the atoms were more important in that picture? The whole picture of reality is precisely that circle, and we are discovering it. The scientist could not discover atoms without the family that raised them, without the house that sheltered them, without the institutions that funded the research. The atoms are there, yes. But so is everything else. They are all required.

Now someone might say: but atoms existed before anyone discovered them. True. But a tree also exists before anyone perceives it if we accept that (and that is a thorny issue but for another time). We discover atoms like we discover any other unit in the world. The only difference is the mode of access. To reach atoms we need instruments in a lab and then deduce their existence in a more abstract way. But this does not grant atoms special ontological status. We do not have some privileged access to atoms that bypasses the macroscopic world. In the same way that a city exists through human perception, an atom is also encountered through human perception (mediated by instruments and inference).

We do not have to cut reality into pieces and declare that whatever excludes the human is more important. That is my point. The fundamentalist wants to say that [1] establishes ontological priority but all it actually establishes is compositional asymmetry. Cities are made of atoms. Fine. But "made of" does not mean "more real than."

The word "fundamental" conceals several different ideas that need to be pulled apart:

[1a] Temporal priority: Atoms were there before cities.

[1b] Modal priority: Atoms can exist without cities but cities cannot exist without atoms.

[1c] Compositional asymmetry: Cities are made of atoms, not vice versa.

[1d] Ontological importance: Atoms are more real.

I accept [1a], [1b], and [1c]. What I reject is [1d]. And [1d] does not follow from the others:

[1a] Atoms came first. True, but being older and simpler does not make something more real. It just makes it older and simpler.

[1b] Atoms can exist without cities. True, but atoms existing alone are just stuff following laws, going nowhere in particular. The interesting reality that does things, that means things, that builds and discovers, emerges only with complexity.

[1c] Cities are made of atoms. True, but a novel is made of ink squiggles. The squiggles do not become a story on their own. You need intentions, meanings, a whole cultural context for there to be a novel at all. "Made of" does not mean "explained by."

Now someone might respond: but the intentions and meanings are themselves just brain states which are also made of atoms. So it is atoms all the way down and the higher levels are just along for the ride.

But this assumes what needs to be proven. Causal completeness (every physical event has a sufficient physical cause) is an assumption, not a proven fact. We do not actually know that physics is causally closed. And even if it were, it would not follow that higher-level descriptions are unreal. Higher-level patterns capture regularities that are invisible at the atomic level. The fact that something is made of atoms does not mean the atomic description is the only real one.

This is usually where the physicalist brings up "emergence." But notice what has happened. If you are saying that higher-level patterns emerge and have their own regularities and causal relevance, you are conceding my point. You are saying these levels matter. You cannot simultaneously claim that atoms are what is really real and that emergent patterns are causally relevant. That is ontological parity by another name.

The fundamentalist slides between these meanings as if they were equivalent. They are not.

Now let us look at what else gets smuggled in. The fundamentalist often appeals to:

[2] Mathematical precision tracks reality. Physics can be expressed in exact equations while complex human realities cannot.

But mathematical tractability tracks simplicity, not fundamentality. A person resists mathematization because their reality is too complex, not because it is less real. If anything this is an argument that the reality of persons is more ontologically dense.

There is also the claim that:

[3] Physics has unique causal powers that higher levels lack.

But this conflates "different" with "better." A mayor changes reality as significantly as an atom bomb, just differently. And the causal influence runs both ways. Create a drum, and the drum contains the water. The drum is a macroscopic object and it is shaping where water molecules go. The molecules still follow physical laws, but which paths they actually take depends on the drum. Higher-level structures constrain what happens at the atomic level just as physics constrains what is buildable. And crucially, a house cannot be explained by its atoms alone. It requires intentions, designs, purposes that are constrained by but not determined by physics. Neither level is sufficient on its own.

To sum up:

Though the fundamentalist claims to derive the hierarchy from [1], in reality they are making additional assumptions that do not follow. The picture I am proposing is ontological and epistemic parity. Atoms, cells, organisms, people, institutions, meanings are all equally real aspects of a single world. I am not inverting the hierarchy. I am saying parity is the default position. If you want to privilege one level as more real, the burden is on you to show why. And [1], [2], and [3] do not actually establish what they claim.