The Cardinality of Experience Is Underdetermined by the Quantum State: A Constructive Case for a Consciousness-Primitive Interpretation

Abstract

Record note (2026-08-17). This record was published on 2026-08-17 carrying the v3 manuscript, and its attached file was replaced the same day with the revised manuscript described below (and replaced once more the same day, to correct two sentences of the abstract that contradicted the body and left a dangling reference); the metadata has been updated to match the file. The DOI is unchanged. Anyone who downloaded the file before that replacement holds the earlier v3 text, whose §8 figures and argument are the same but which contains the two errors corrected below. Version 4 (2026-08-17) — change note. Two corrections and an editorial revision. The corrections are the reason this version exists. Corrections. First, the rebuttal of the “experimenter’s height” objection assumed its own conclusion. The previous text said that height is fixed by facts in the world whereas experiential cardinality is not — but whether cardinality is fixed by inaccessible global facts is precisely what claim (E) leaves open, as the same paragraph went on to concede. The claim is now scoped correctly: cardinality is not fixed by the operational content itself, and an interpretation may still ground it in the global state, thereby accepting (E) and rejecting the further premise (P). Second, the repeated claim that every no-collapse interpretation must add a posit was too strong, and was contradicted by the paper’s own menu table, which describes Wallace’s functionalist identification as an analysis that adds no entity. Throughout, this is now the weaker and correct claim: each interpretation owes a bridge, an identification, or a posit fixing the experiential facts. Editorial revision (following external editorial review; 27 pp → 23 pp). §2 is resequenced so that the formal statement of the claim (§2.3) precedes the computational illustration (§2.4), which is now described as a narrower illustration of the factorization logic rather than a measured instance of (E). The former §5 and §6 are merged into §5, “What Changes — and What Does Not”; the trade-off table of the former §9 is folded into §5.1; the Φ ≤ S material becomes §7, “Empirical Outlook”, with its withdrawal and falsifiability diagnosis retained and the quantum-cognition paragraph dropped. The introduction is rebuilt around four limits stated once rather than repeated throughout; the unasserted maximal claim (M) is removed; the witness-unity premise is now stated independently in the author’s own terms, with the Advaitic sākṣin tradition offered as one historically developed articulation rather than as its warrant; and §4.4’s caveat on the correspondence table no longer undermines the table it qualifies. Sections are renumbered §1–§8. The §8 figures, the withdrawal of Φ ≤ S, and the argument of §2–§7 are unchanged in substance. Code Availability continues to pin commit fa19ead. Quantum mechanics and the metaphysics of consciousness are usually pursued apart; this paper joins them with a result and an interpretation. The result: the number of unified subjects of experience — the cardinality of experience — is not fixed by anything operationally accessible to a localized perspective in a no-collapse setting; we state the claim precisely and illustrate it with a computational instance. The significance of the result lies less in the underdetermination itself than in what follows from it: the decombination problem (the standard objection to cosmopsychism) and Everett's how-many-minds problem instantiate the same cardinality underdetermination seen from opposite sides, meaning the dialectical cost is shared, not a special liability of consciousness-first views. The non-determination isolates what every no-collapse interpretation owes: an account of what fixes the experiential facts. Taking that as ground yields a structural cosmopsychism on which a universal subject's self-relational structure is the Hilbert-space structure. Advaita Vedānta supplies illuminating labels for moves the view defines independently.