NOTE-112: Poltorak — Wave-function realism and causal closure

Contribution

The paper separates two parameters of “every physical effect has a sufficient physical cause”. The first is the domain D (spatiotemporal, fundamental-physical, or a level L). The second is the completeness relation: dynamical, causal or explanatory (§2.2). It then shows how each realist quantum ontology sets them differently. The upshot is that the “criterion problem” for the physical — Hempel’s dilemma, Montero’s body problem — can no longer be deferred by a physicalist who uses closure against dualism.

Key insight

The move from “the wave function is not in spacetime” to “something non-physical causes spacetime events” needs an extra premise: that a structure not instantiated in spacetime is a non-physical external cause (§4.2, p. 11). That premise is exactly what wave-function realists and theory-based physicalists deny. Once it is dropped, what remains is a problem about the scope of closure, not a breach.

Assumptions

• Non-relativistic, idealised QM for the configuration-space picture. Ney (2021, 2023) is followed in treating it as an interpretation of that idealisation (§3.1).
• Wave-function realism is assumed only conditionally (§4.1: “conditional and diagnostic”).
• Neutrality between theories of causation. Causal sufficiency is relativised to deterministic or probabilistic standards (§2.2).
• PBR is read in the ontological-models framework (Harrigan–Spekkens). Its preparation-independence assumption is noted (§3.2).
• A non-stipulative reading of “complete” in FPC: true and ontologically exhaustive, not complete by definition (p. 6).

Key results

• Three completeness relations (p. 5): dynamical completeness, causal closure and explanatory completeness. “Dynamical completeness therefore supports causal closure only together with a bridge principle.”
• STC versus FPC (p. 6). STC excludes only extra-spatiotemporal, Cartesian-style causes, not property dualism. Nonlocality and fields do not break STC; “a fundamental ontology whose arena is not spacetime at all” does.
• PBR’s limits (§3.2). ψ-ontic means only disjoint supports over λ. The theorem does not locate the ontology in a space, and does not choose among WFR, primitive ontology, dispositional or nomological readings.
• The Scope Argument (§4.1). P1–P7 lead to C1: WFR undermines STC but not FPC. C2: there is a scope and criterion problem, not a trans-domain breach. C3: both tacit parameters must be made explicit.
• Robustness (§5). WFR rejects STC and retains FPC and LRC. Primitive ontology and Bohmian mechanics keep a spacetime domain with nonlocal dependence, which is “not influence from outside the physical”. Spacetime-state realism breaks pointillist STC but may keep region-based STC; in AQFT the local algebras are Type III (Swanson 2020). Multi-field realism defeats the claim that ψ-realism forces a separate high-dimensional realm. Everett adds derivative branch structure only. The pattern: the finer-grained the closure domain, the likelier a quantum ontology violates it.
• Mind (§6). Nonspatiotemporality does not entail nonphysicality. Stochastic dynamics leaves no “mental causal slot”: a mind-modified collapse law is new dynamics and a rival hypothesis (Chalmers and McQueen 2022 is cited as explicit and testable). Bell nonlocality plus no-signalling gives nothing for controllable mental influence.
• Six objections (§7). The concession that sophisticated closure was never spacetime-restricted is “the argument” (§7.1). Theory-based physicalism resolves the quantum case but does not exclude fundamental mentality (§7.2). Bohmian counterfactual dependence gives at most a causal role inside physics (§7.3). Vacuity worries are real but met by the constraints of physical theory (§7.4). The argument is robust across interpretations (§7.5). Formal causation does not repair the breach inference (§7.6).

Claims

id	claim	strength	support
C1	WFR, if true, falsifies STC but is compatible with FPC	moderate	informal argument from definitions P3–P5 (§4.1); close to analytic once STC and FPC are defined
C2	No trans-domain causal breach follows from WFR	moderate	informal argument (§4.2): the breach requires an extra, question-begging premise
C3	Dynamical completeness does not by itself give causal closure	weak	asserted as P7, citing Ney 2016; a bridge is required but not argued for or against
C4	Quantum ontology makes the criterion of physicality non-deferrable	moderate	informal argument (§1, §7.1); weakened by the concession that sophisticated physicalists already state closure as FPC
C5	Fundamental stochasticity creates no slot for mental causes	moderate	informal argument (§6.3): a mind-modulated chance law is a new dynamical hypothesis
C6	Appeals to Hilbert space, PBR, the Born rule or Bohmian guidance cannot yield a breach	moderate	informal argument (§§3.1–3.2, 4.2)
C7	The finer-grained the closure domain, the likelier a quantum ontology violates it	weak	generalisation from the §5 cases

Method

A conceptual analysis. The paper first fixes a parameterised schema C(D) and separates the three completeness relations. It then states the Scope Argument, and tests the resulting distinctions against five families of realist quantum ontology plus six objections.

Concepts

• C(D): for every physical effect E that has a cause, there is a basis B wholly in D that is causally sufficient, deterministically or by fixing E’s objective chance (p. 5).
• STC, spatiotemporal-domain closure: sufficient bases consist only of what is instantiated in ordinary spacetime (p. 6).
• FPC, fundamental-physical closure: sufficient bases lie within the total ontology and laws of a complete fundamental physical theory, “whatever representational or spatial structure that theory requires” (p. 6).
• LRC, level-relative explanatory closure: at a level L, effects have sufficient explanations or difference-makers available at L, conditional on realization relations. It is a claim about derivative explanation only (p. 6).
• Criterion problem: saying what counts as physical — Hempel’s dilemma, the body problem (§2.3).

Connections

Poltorak’s test cases are Chen’s taxonomy (LIT-204). The paper cites Belot (LIT-100) for the primitive ontologist’s options, and its §5.4 point — that nomological and dispositional readings separate ontic status from causal status — applies to Allori (LIT-200) and to Dorato’s powers reading (LIT-176). Its reading of PBR (LIT-062), that ψ-ontic in the technical sense does not select an ontology, matches the record’s reading of the theorem and of Hance et al. (LIT-090). Its remark that Hilbert-space realism “would be a further metaphysical thesis requiring its own argument” (§3.1) bears on Carroll’s LIT-123. On the philosophy-of-mind side it adjoins Pernu’s treatment of causal exclusion (LIT-144). Both papers separate closure-type premises from what exclusion arguments actually need.

Metaphysics. The work defends a thesis about the formulation and scope of the causal closure of the physical, and about what physicalism must supply: a criterion of physicality, a bridge from dynamics to causation, and an account of dependence. That is squarely causation and levels. The metaphysics tag is justified, and should lead (see corrections).

Bearing on the record

It bridges the wave-function cluster and the mental-causation and physicalism material (LIT-144). It supports no THEORY document. Nothing for ML practice.

Note of 2026-10-16: THEORY-485 now cites LIT-164 as a source.

Note of 2026-10-20: of the three cited accounts, Chalmers and McQueen has now been read in part (LIT-1284, NOTE-1012). The paper’s representation of it, as a mind-modified collapse law that is new dynamics and an explicit, testable rival hypothesis, is accurate. Those authors also argue that collapse is a gap in causal closure, and whether their law is fundamental physics is the criterion-of-the-physical problem in §7.2. Ney (2021) and Bikaraan-Behesht (2022) remain unread: neither has an open-access copy that Unpaywall, OpenAlex or Semantic Scholar know of.

Limitations

• By its own account (§8.4) it does not defend WFR, solve the macro-object problem, adjudicate among interpretations, treat QFT fully, supply a theory of causation, or establish physicalism or dualism.
• The target is conceded to be a picture, not a published argument (p. 2, §7.1). That makes the positive contribution chiefly the parameter framework.
• P7 is doing essential work and is asserted.
• The representation of the cited literature was not checked against the sources when this was read. Chalmers and McQueen has since been checked (dated note of 2026-10-20); Bikaraan-Behesht 2022 and Ney 2021 remain unverified.

Open questions

• What bridge principle would carry dynamical completeness to causal closure, and is any available across stochastic theories?
• Which criterion of physicality admits the wave function but excludes fundamental mentality without stipulation (§7.2, §7.4)?
• Does the scope framework carry over when spacetime is emergent in quantum gravity (§8.3)?

Corrections to the seeded skim

• The Scope Argument (§4.1, p. 10) has seven premises, P1–P7, and three conclusions, C1–C3, not “premises P1–P6”. P7, that quantum theories deliver dynamical structure and not a causal metaphysics, is the premise the dossier flagged as load-bearing (the dynamical-to-causal bridge). It is asserted, with Ney (2016) cited (§2.2), not argued. The paper’s own limitations section (§8.4) says it does not settle “how the bridge … is best secured”.
• The dossier’s summary reads as if the paper rebuts an existing position. It does not. The author says he has “found no published argument that moves from wave-function realism to the conclusion that causal closure is breached” (p. 2). He also concedes (§1, p. 3; §7.1) that sophisticated closure formulations, Papineau’s, are not spacetime-restricted, so the target is “the picture from which closure borrows its intuitive force”.
• The dossier omits a third notion, level-relative explanatory closure (LRC, §2.2, p. 6). It is explicitly not a third causal-closure principle, and it does work in §§5.1, 5.3 and 6.2.
• The dossier suggests consciousness as an extra tag. Not justified: the subject is mental causation and physicalism, and consciousness enters only through §6.3’s discussion of consciousness-collapse proposals (Wigner, Stapp, Chalmers and McQueen). The topic’s blurb is phenomenal consciousness and its attribution.
• primary topic: metaphysics — the work’s subject is the causal closure of the physical and the formulation of physicalism, which are causation and levels in the metaphysics blurb. Quantum ontology is its test case, not its topic.