REVIEW 3 major objections 6 minor 2 references
Non-individuality and experience
T0 review · 3 major / 6 minor · reviewed 2026-08-07 · deepseek-v4-flash
Pith's one-line read The non-individuals interpretation of quantum mechanics can only explain experience if it leaves standard quantum mechanics behind.
desk verdict Useful diagnosis of QMNI's Crisp-axiom problem, but the 'open venue' recommendation overstates what Everett and collapse theories actually supply. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The Crisp axiom (C) of quasi-set theory is the load-bearing device: $\forall x (m(x) \to (C(x) \to M(x)))$, a predicate that turns a non-individual quantum atom into an individual one. In the paper’s diagnosis, C is the formal equivalent of the collapse of the wavefunction in standard quantum mechanics, and therefore inherits the same defect: it depends on an undefined “measurement” event. The paper’s argument is that C can only do its phenomenal work if it is anchored to a physical mechanism, such as decoherence-driven branching in Everettian quantum mechanics or the objective collapse rate in spontaneous collapse theories.
What would settle it
One concrete test is to check whether an unambiguous empirical confirmation of Bohmian particle trajectories ever occurs; the paper explicitly grants that if Bohmian mechanics were confirmed, QMNI would be falsified.
Extended reading notes
Core claim
On the paper’s own terms, the central claim is that QMNI as currently formulated is incomplete: it tells us the world’s basic entities are non-individuals but gives no account of how those non-individuals compose the individual objects of experience. The bridge must be supplied by the Crisp axiom, which turns m-atoms into M-atoms, or by some analog. But because the Crisp axiom was introduced to mark “measurement” in standard quantum mechanics, and because standard quantum mechanics never defines measurement, QMNI cannot stay attached to it. The paper therefore argues that QMNI should be reformulated within a solution to the measurement problem: Everettian branching or spontaneous collapse can ground the Crisp transition, while Bohmian mechanics confers a spatiotemporal individuality incompatible with QMNI and the Modal-Hamiltonian Interpretation would require QMNI to abandon the category of object.
Load-bearing premise
The whole argument depends on accepting the Phenomenological principle as the right standard, namely that any ontology must suffice to account for appearances; if that principle is rejected, QMNI’s need for a Crisp axiom loses its force.
Editorial extensions
If this is right
- QMNI must abandon the collapse postulate of standard quantum mechanics as its metaphysical foundation.
- In an Everettian setting, the Crisp axiom would be redefined through branching and decoherence rather than through measurement.
- In a spontaneous collapse setting, the collapse rate would provide the physical trigger that turns non-individual m-atoms into individual M-atoms.
- Empirical support for Bohmian mechanics would directly falsify QMNI, while support for spontaneous collapse or Everettian quantum mechanics would keep it viable.
- Compatibility with the Modal-Hamiltonian Interpretation is possible only if QMNI drops the ontological category of object altogether.
Reading between the lines
- The paper leaves open whether the Crisp axiom’s m-to-M transition has a quantitative threshold; one testable extension would be to derive such a threshold from the decoherence rate or collapse rate in whichever interpretation QMNI is attached to.
- The same structure could be applied to quantum field theory, where particle-number indeterminacy may make the m-to-M transition even less well defined than in non-relativistic quantum mechanics.
- If branching is the trigger, the acknowledged vagueness of world-count in Everettian quantum mechanics would transfer to the Crisp transition, so any precise statement of when individuality emerges would inherit that vagueness.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The chapter argues that the “non-individuals” interpretation of quantum mechanics (QMNI), which treats quantum entities as objects lacking an individuality profile within quasi-set theory, faces a challenge from Shimony's Phenomenological principle: any acceptable ontology must suffice to account for appearances, and our world of experience is populated by individuals. The paper's thesis is that QMNI requires the Crisp axiom (C) of quasi-set theory — the predicate that turns m-atoms into M-atoms — or an analog of it, but that C as originally conceived is triggered by the undefined notion of “measurement” in standard quantum mechanics (SQM). The chapter therefore recommends detaching QMNI from SQM and attaching it to a principled solution to the measurement problem. Section 4 surveys four interpretations: Bohmian mechanics and the Modal-Hamiltonian Interpretation are presented as closed venues (though MHI is said to admit a future “bridge”), while Everettian quantum mechanics and spontaneous collapse theories are proposed as viable alternatives, with the Crisp trigger replaced by branching or by the GRW collapse rate, respectively. Section 5 concludes that QMNI must adopt the Crisp axiom, must abandon SQM, and that attaching QMNI to Everett or collapse theories makes “the job fairly easy,” while leaving detailed articulation to future work.
Significance. If the diagnosis holds, the chapter advances the QMNI program: identifying the Crisp axiom's dependence on SQM's undefined “measurement” is a substantive contribution to the recent literature on C (Macías-Bustos and Martínez-Ordaz 2023), and reframing the task as finding a principled trigger for C is a useful research directive. The chapter is commendably honest: §2 states explicitly that the composition question (how a collection of non-individual m-atoms composes an individual M-atom) remains unanswered, and §5 concedes that C “won't do the entire job.” The survey connects QMNI to the interpretation wars and yields a testable commitment: empirical vindication of Bohmian mechanics would, on the paper's trajectory-based individuality claim, falsify QMNI. The chapter credits adjacent recent work (Lombardi 2023; Holik et al. 2022) and identifies concrete candidate triggers for C. The significance is programmatic rather than definitive — the chapter reframes a known gap and charts routes forward without closing the gap — but that reframing is valuable both for the non-individuality school and for its critics.
major comments (3)
- [§4 (Everett, GRW); §5] The paper's central recommendation — that attaching QMNI to Everettian quantum mechanics or to spontaneous collapse theories makes “the job fairly easy” (§5) — is not supported by the argument offered. The paper itself acknowledges in §2 that “the crucial question that remains unanswered is that, even if we fix the Phenomenological principle, how come an individual (a M-atom) can be formed by a collection of non-individuals (m-atoms)?” The Crisp axiom stipulates the formal transition m(x) → M(x), but neither the Everett discussion (“the non-individuality of m-atoms would, as soon as the world branches, become M-atoms”) nor the GRW discussion (“there is no problem with the Phenomenological principle here”) supplies an account of how the composition is effected. Replacing the trigger of C (measurement by branching or by collapse rate) leaves the m → M transition as stipulative as before; the survey's evidence that these interpretations are “open” is an absence of conflict (no trajectories, no objective objects), which is not positive evidence that the Crisp transition can be made principled. Because the Phenomenological principle requires the ontology to “suffice to account for appearances,” the unanswered composition question is load-bearing: the compatibility claim asserted in §5 is weaker than the conclusion requires, and the paper should either restrict its claim to the trigger problem (with the composition problem explicitly deferred) or show, in outline, how branching or collapse bears on composition.
- [§1; §5] The paper's central necessity claim — that QMNI “must have the Crisp axiom (C), or some analog of it” (§5) — rests on Shimony's Phenomenological principle as quoted in §1, and the principle is not defended beyond the citation to Shimony (1997). The only additional support offered, the appeal to French (2018) on new metaphysical devices needing to relate to familiar ones, is explicitly subsumed by the author under the same principle (“I take that French's claim can be read as an instance of Shimony's Phenomenological principle”). The paper explicitly declines to use the principle to falsify QMNI outright, yet still deploys it as the standard that generates the Crisp requirement and that makes the measurement problem a problem in §3. A reader who rejects the principle (for instance, a philosopher who denies that fundamental ontology must “account for appearances,” or an eliminativist about the manifest image) will see no reason for the Crisp axiom at all, and the entire compatibility survey loses its force. The chapter should either provide an independent argument for the principle or explicitly conditionalize the thesis: if the Phenomenological principle is accepted, then QMNI requires C or an analog, and C requires a principled trigger. As written, the modal strength of the conclusion (“must”) exceeds the support provided, although the paper is transparent about the reliance.
- [Abstract; §4; §5] There is an internal tension in the classification of the Modal-Hamiltonian Interpretation. The abstract announces “two closed venues” (Bohmian mechanics and MHI), and §5 says QMNI is “incompatible” with both. But the MHI subsection of §4 argues that recent MHI's elimination of the category of “object” creates only “a tension” with QMNI “as it presently stands,” that “some modifications in the ontological categories of QMNI are needed,” and §5 itself concedes that “a bridge might be built” if QMNI adopts eliminativism about objects. Since the paper describes a concrete path to compatibility, and since Holik et al. (2022) have already built an MHI on quasi-set theory, grouping MHI with the “irreconcilable” Bohmian case obscures the survey's structure. Either MHI should be classified as a separate conditional case, or the paper should explain why the required modification to QMNI's ontology counts as disqualifying for the “as it currently stands” claim.
minor comments (6)
- [§3] In §3, “QM NI stand or fall with the SQM collapse postulate” should read “QMNI stands or falls with the SQM collapse postulate” (subject–verb agreement).
- [§2] In §2, “it let to an instance of the (in)famous measurement problem” should read “it led to an instance.”
- [§4 (Everett)] In the Everett subsection, the sentence “the non-individuality of m-atoms would, as soon as the world branches, become M-atoms” conflates a property (non-individuality) with its bearers (m-atoms); the intended claim is presumably that m-atoms become M-atoms while losing their non-individuality.
- [§4 (Bohmian)] The verdict that Bohmian mechanics is “not a venue for QMNI” rests on the claim that trajectories confer individuality, which is asserted with citations (Brown, Dewdney and Horton 1994; Redhead 1983; French and Bigaj 2024) but not defended against known dissent in the literature; since the conditional falsification claim in §5 depends on this premise, a sentence of argument would materially strengthen the chapter.
- [§4 (GRW)] The GRW subsection says “the more complex the system is, the more likely to collapse”; stating the effective rate scaling (roughly the single-particle rate times the number of constituents) would make the trigger story more precise.
- [References] The reference entry for Brown, Dewdney and Horton (1994) lists “Foundations of Physics A 25,” and the Krause and Jorge (2024) entry contains a malformed URL with stray spaces (“https ://philpapers.org/rec/KRASUT”); both need cleanup.
Circularity Check
No significant circularity: the central argument rests on Shimony's external Phenomenological principle and on published characterizations of rival interpretations, and the paper explicitly leaves the hard composition question open.
full rationale
The paper does not derive its conclusions from its own prior results or from a self-citation chain. The load-bearing premise, Shimony's Phenomenological principle, is quoted from an external source (§1) and is used as a constraint rather than as a conclusion. The Crisp axiom is introduced from Krause (2012) and Macías-Bustos and Martínez-Ordaz (2023), and the paper's central move is to criticize the way that axiom is tied to the undefined notion of measurement in standard quantum mechanics (§3, §5). The claim that QMNI needs C or an analog restates what C is defined to be—the transition from m-atoms to M-atoms—but the paper does not present this as an empirical prediction or as a solved derivation; it explicitly says 'The introduction of C, however, won't do the entire job' (§5) and identifies the unresolved composition question as the crucial remaining problem. The compatibility survey is based on external characterizations of Bohmian mechanics, MHI, Everettian quantum mechanics, and GRW collapse theories, and the negative verdicts for Bohmian mechanics and MHI are drawn from the content of those interpretations rather than from the author's own authority. The final suggestion that attaching QMNI to Everett or collapse theories makes the task 'fairly easy' is under-argued and may be a substantive gap, but it is not circular: the supporting premises do not already contain the conclusion. No fitted input is renamed as a prediction, and no uniqueness theorem is imported from the author's own prior work.
Assumptions & free parameters
assumptions (4)
- domain assumption Shimony's Phenomenological principle: whatever ontology a coherent philosophy recognizes, that ontology must suffice to account for appearances.
- domain assumption Individuality reduces to identity in the haecceitistic sense, so the failure of self-identity (∀x(x=x)) captures non-individuality.
- domain assumption The Crisp axiom C, which transforms m(x) to M(x), is the formal bridge required by the Phenomenological principle.
- domain assumption Bohmian mechanics confers individuality via definite spatio-temporal trajectories.
Cite this review
Pith. "Pith review of Non-individuality and experience." pith.science (2026). https://pith.science/paper/TWNTUJTZ
@misc{pith2026250515627,
author = {Pith},
title = {Pith review of: Non-individuality and experience},
year = {2026},
howpublished = {\url{https://pith.science/paper/TWNTUJTZ}},
note = {Machine review of arXiv:2505.15627}
}
read the original abstract
This chapter acknowledges a gap between the ``non-individuals'' interpretation of quantum mechanics and our world of experience, and begins to bridge it. Section 1 states the problem with Abner Shimony's ``Phenomenological principle''; section 2 briefly presents the interpretation with connection to standard quantum mechanics; section 3 presents the measurement problem in connection with the Phenomenological principle, the standard way out of it, and why the ``non-individuals'' interpretation of quantum mechanics should not follow it; section 4 finally shows two closed venues for such an interpretation (Bohmian mechanics and the Modal-Hamiltonian Interpretation), and two alternatives for such it (Everettian quantum mechanics and spontaneous collapse theories).
Reference graph
Works this paper leans on
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[1]
Albert DZ (1992) Quantum mechanics and experience . Harvard University Press, Cambridge Arenhart JRB (2017) The received view on quantum non-individuality: formal and metaphysical analysis. Synthese 194(4), pp. 1323–1347 Arenhart JRB (2023) A no-individuals account of quantum mechanics.Philosophical Transactions of the Royal Society A: Mathematical, Physi...
work page 1992
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[2]
On Mentality, Quantum Mechanics and the Actualization of Potentialities
Philosophy of Science Association, East Lansing, pp. 57–99 Shimony A (1997) “On Mentality, Quantum Mechanics and the Actualization of Potentialities” The Large, the Small and the Human Mind ed. by M Longair Cambridge University Press, Cambridge Toraldo di Francia G (1978) What is a physical object?.Scientia 113, pp. 57–65 von Neumann J (1932)Mathematische...
work page 1997
Reviewed August 7, 2026 · model on record in the stance chip above.
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