What physicalism commits us to
Physicalism makes a claim about the foundations of reality. Its success depends on explaining experience, rather than merely locating the machinery associated with it.
A universe composed of physical processes can still contain grief, tenderness, understanding, and beauty. Whether those things are wholly physical is a further question. Their importance to a life does not disappear simply because an account places them within nature.
Physicalism becomes interesting at the point where it makes a stronger commitment: every fact about experience must ultimately depend on, or be constituted by, the physical character of reality. If two worlds were physically identical in the relevant complete sense, they could not differ in what was experienced. The view owes us a relationship between the physical description and the lived fact.
That is a considerable obligation. It is also a more serious position than the claim that only things visible to a laboratory instrument exist.
A commitment beyond a method
As Daniel Stoljar explains, physicalism has several formulations, including identity, realization, and grounding accounts. It accommodates more than the old image of solid particles moving through empty space. Contemporary physics has already made that image inadequate as a description of the physical world.
A practice of investigating physical mechanisms does not require a prior verdict that physical mechanisms exhaust reality. A researcher can study the causes of a perceptual report while leaving the metaphysics of experience unresolved. Conversely, a physicalist can believe the metaphysics has an answer while acknowledging that the mechanism is still poorly understood. Method, evidence, and ultimate commitment can come apart.
This matters when the achievements of science are enlisted as a complete argument for an ontology. A successful intervention demonstrates something about the processes involved. The additional conclusion that those processes leave nothing else to explain needs its own defence.
The account experience demands
The difficulty is easiest to state from the inside. A complete account must accommodate that an event is undergone. Listing the operations involved in recognition, attention, and report can explain how an organism manages information. The contested step is whether that account also explains the presence of experience.
Chalmers argues that explaining functions leaves a further question about their phenomenal character. Physicalists dispute whether the remaining gap is a gap in reality, a limitation of our concepts, or a misleading demand for another kind of explanation.
The editorial judgment here is that the felt character of existence remains a substantive explanatory obligation. An account should identify the relationship it claims, then explain why that relationship is sufficient. Describing experience as emergent postpones the problem unless the emergence itself becomes intelligible.
There is nevertheless a danger in declaring that physical description can never succeed. Such a declaration claims advance knowledge of every possible future account. Present explanatory failure is significant evidence about present theories. Its force does not depend on proving that inquiry must fail forever.
Consequences that do not follow automatically
Physicalism does not by definition entail causal determinism. It does not by itself select presentism over eternalism, either. Those positions concern different features of the world: the foundations of things, the relation between states and laws, and which temporal events exist.
Nor does physicalism establish that meaning is fraudulent. A commitment can depend on biological capacities and still matter to the being whose capacities they are. If pain is wholly physical, its reality as pain remains precisely what needs accounting for. Explaining its basis supplies no reason to ignore it.
The stronger criticism concerns explanatory completeness. A worldview becomes premature when its confidence outruns its account of the phenomena it includes. That is where consciousness exerts pressure: it requires the description of a world to accommodate the existence of a perspective within it.
Eternalism sharpens this requirement without resolving it. A complete temporal history could contain every neural event and every report about awareness. We would still need an account of how those events relate to what was lived. The depth of the record and the presence of experience remain distinct questions, both worth pursuing to their foundations.