REVIEW 3 major objections 5 minor 22 references
Are Events Absolute?
T0 review · 3 major / 5 minor · reviewed 2026-08-06 · deepseek-v4-flash
Pith's one-line read The paper argues that quantum mechanics leaves no room for absolute measurement outcomes.
desk verdict A competent review that overclaims: the no-go derivation is a disjunctive contradiction, and the paper's own undoability caveat undercuts the conclusion that events are observer-relative. 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 machine that carries the argument is the nested two-friend, two-observer setup. Two friends, each inside a sealed laboratory, share an entangled pair prepared in the Hardy state $\psi = (|00\rangle + |01\rangle + |10\rangle)/\sqrt{3}$ and measure their particles in the 0/1 basis. Two external observers, Alice and Bob, can either ask a friend for the recorded result or undo that friend's measurement and measure in the $\pm$ basis. The derivation uses four probability equalities, for instance $p(c{=}1,d{=}1 \mid x{=}0,y{=}0)=0$ and $p(a{=}-,b{=}- \mid x{=}1,y{=}1)=1/12$, and then locality projects them onto the single run with $x{=}1,y{=}1$. Those projected probabilities force the implication chain $(a=-) \Rightarrow (d=1) \Rightarrow (c=0) \Rightarrow (b=+)$, making $p(a=-,b=-)=0$, which contradicts the value $1/12$ from the same run. That mechanical contradiction is what compels dropping one of the five assumptions, and the paper's stated resolution is to drop the absoluteness of observed events.
What would settle it
A real experiment that attempts to undo the measurement record of a genuinely macroscopic observer and restore interference would settle the question: if the record cannot be re-cohered, the undoing assumption fails and events may be absolute; if it can, the no-go contradiction applies.
Extended reading notes
Core claim
The paper's central claim is that the extended two-friend, two-observer version of the friend-in-the-box scenario, run with a Hardy state, produces a contradiction for anyone who holds five assumptions at once: locality for observed events, no superdeterminism, universal validity of quantum mechanics, absoluteness of observed events, and the possibility of undoing a measurement. The derivation yields four probability equalities that, after a locality step, constrain a single run to satisfy both $p(a=-,b=-)=1/12$ and an implication chain forcing $p(a=-,b=-)=0$. Because the contradiction only arises if the same four results are taken to coexist, the paper concludes that at least one assumption must be dropped; in practice the one usually dropped is the absoluteness of observed events. That is the sense in which events are not absolute: an event has a definite occurrence or outcome only relative to the observer who measures it.
Load-bearing premise
The load-bearing premise is that an outside observer can in principle undo a friend's completed measurement, together with the locality-based step that transfers probabilities between different measurement settings; if either fails, the contradiction dissolves.
Editorial extensions
If this is right
- Under the five assumptions, no consistent assignment of absolute facts exists for the two-friend scenario; the same run must satisfy both $p(a=-,b=-)=0$ and $p(a=-,b=-)=1/12$, which is impossible if events are absolute.
- The usual casualty is absoluteness of observed events: a result like 'Charlie got spin up' is true only relative to a designated observer, not as a fact of the universe.
- There is no 'view from nowhere' in quantum mechanics; statements that combine two observers' results are not meaningful unless they are made from one observer's perspective.
- Asking another observer for their result does not resolve the issue: the question-and-answer process is itself a measurement, and the answer heard is consistent with the asker's relative facts.
- Photonic simulations of the friend are illustrative but not decisive, because an interaction with a photon is not clearly a measurement by an observer, and a real macroscopic undoing is beyond any conceivable technology.
Reading between the lines
- The paper leaves implicit that a fully relational account would need to say what 'probability' means when two observers' relative facts cannot be compared; this is a constraint any perspectival interpretation must satisfy.
- The undoing premise suggests a concrete research direction: search for violations of interference at ever-larger record sizes, since a failure at some scale would replace the no-go contradiction with a boundary for quantum universality.
- If the contradiction is right, standard quantum error correction and computation, which assume a single objective readout, may need a branch-relative notion of computation; this is not discussed in the paper.
- The no-go result does not uniquely select the author's convivial solipsism; other perspectival readings could accommodate relative events, so the paper's interpretive conclusion goes beyond its formal result.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. This manuscript is a general review of Wigner's-Friend-type thought experiments and their implications. After recapitulating the original scenario and surveying interpretations (Copenhagen, many-worlds, relational QM, objective collapse, QBism, and the author's own Convivial Solipsism), the paper presents a simplified extended-Wigner's-Friend no-go argument based on the Hardy state and five assumptions: locality for observed events, no superdeterminism, universality of quantum mechanics, absoluteness of observed events, and the possibility of undoing a measurement. The argument derives probability equalities that, when combined by locality, yield a contradiction, and the paper concludes that at least one assumption must be abandoned, usually absoluteness of observed events. The final sections discuss implications for realism, quantum information, and the author's Convivial Solipsism interpretation.
Significance. The paper has genuine expository value: it condenses a well-known no-go argument into a compact derivation, and the four probability equalities in §4.3 are elementary and checkable from standard quantum mechanics. The manuscript is also honest in flagging the difficulty of the undo assumption in §4.4. However, the significance as a research contribution is limited by a gap between the no-go result actually proved and the advertised conclusion. The derivation shows that the five assumptions are jointly inconsistent; it does not show that absoluteness of observed events, rather than one of the other assumptions, is false. Since the paper's own caveat about undoing a measurement points toward a natural way to escape the contradiction without abandoning AOE, the central claim that 'events are no longer absolute' is not secured. The paper is best read as an interpretive essay and review rather than a proof of observer-dependent facts.
major comments (3)
- [§4.3, equalities 5–7] The locality-based transfer from settings (x=0,y=1) and (x=1,y=0) to the single run (x=1,y=1) presupposes that Charlie's outcome c and Debbie's outcome d are well-defined facts even when Alice and Bob undo the corresponding friend measurements. This is precisely what the paper itself doubts in §4.4: 'If Wigner undoes the measurement done by Charlie, it becomes difficult to consider that the result of Charlie's measurement is still a fact.' Without a supplementary rule specifying whether an undone outcome remains an event, the probabilities p(c=0,b=−|x=1,y=1) and p(a=−,d=0|x=1,y=1) are undefined, and the contradiction chain (a=−)⇒(d=1)⇒(c=0)⇒(b=+) has no well-defined starting point. The derivation therefore does not go through under the assumptions as stated.
- [§4.3, final paragraph] The argument establishes only that the conjunction of assumptions 1–5 is inconsistent. The statement 'So we have to abandon at least one of them. Usually, it is the absoluteness of observed events (AOE) that is abandoned' reports an interpretive convention; it does not follow from the derivation. Since §4.4 explicitly raises a serious difficulty for assumption 5, rejecting AOE is not the unique or even the most natural resolution. To support the abstract's claim that 'it is no more possible to consider events as absolute', the paper would need either a defense of assumption 5 against the §4.4 objection or an independent argument that singles out AOE.
- [§4.3, introduction] The paper criticizes Brukner's theorem for relying on 'too strong assumptions (namely to compare results that cannot be obtained in a single experiment)', yet the derivation presented here also combines probability equalities obtained under different settings (equalities 1–4) into statements about a single run (equalities 5–8) using the locality assumption. This move can be legitimate in a Bell-type argument, but the paper applies a stricter standard to Brukner's theorem without explaining why its own use of locality is not vulnerable to the same objection. A precise formulation of 'locality for observed events' — in particular the counterfactual status of outcomes in runs where the measurement is undone — is needed.
minor comments (5)
- [§4.3/§4.4] The section numbering is duplicated: '4.3 Experimental Realizations' follows '4.3 Other no-go theorems', and '4.4 A few reservations' should be renumbered accordingly.
- [Abstract and §7] The abstract says 'no more possible to consider events as absolute', while the conclusion says these results 'suggest' an inherent tension; the paper should commit to a consistent strength of claim, or explicitly frame the conclusion as conditional on accepting all five assumptions.
- [§4.3] The equalities 1–4 are described as easy to verify, but no explicit unitary operators for the friends' measurements or for the undo operations are provided; at least a brief derivation or a table of the relevant states would make the argument reproducible.
- [Throughout] There are numerous typos and grammatical slips, e.g., 'Debby' vs 'Debbie', 'prof oundly', 'the n', 'wh en', 'in the base' should be 'in the basis', and 'stronger assumptions that those made in ConSol' should read 'than those'.
- [References] Reference [17] is a YouTube video and is not an appropriate scholarly citation for a published paper; references [18] and [20] would benefit from full publication data.
Circularity Check
No significant circularity: the no-go derivation is self-contained; the title-level conclusion is under-argued but not circular.
full rationale
The paper's central derivation (§4.3) is a self-contained no-go argument. It states five hypotheses, specifies the Hardy state and the measurement bases, computes the four probabilities (eqs. 1–4), then uses the locality assumption to carry them to a single run (eqs. 5–8) and uses absoluteness of observed events to derive the chain (a=−)⇒(d=1)⇒(c=0)⇒(b=+), contradicting p(a=−,b=−)=1/12. None of these steps defines a quantity in terms of the conclusion it is supposed to prove, and no fitted parameter is relabeled as a prediction. The subsequent advocacy of Convivial Solipsism (§5) invokes the author's own earlier papers, but that interpretation is not used as a premise in the derivation; it is presented as one possible way to resolve the contradiction. The author explicitly flags assumption 5 as the weak point (§4.4), which is a caveat about the argument's soundness rather than circularity. The gap between the disjunctive conclusion ('abandon at least one of them') and the title-level claim that events are not absolute is a logical-strength issue, not a circularity issue, because the paper does not pretend the contradiction singles out AOE by construction. Thus no circular step can be quoted.
Assumptions & free parameters
assumptions (8)
- domain assumption Quantum mechanics is universal: it applies to all physical systems, including macroscopic ones and observers.
- domain assumption No-superdeterminism: future choices of measurements are not predetermined by hidden variables.
- domain assumption Locality for observed events: measurements in one lab do not instantaneously affect distant labs.
- domain assumption The wave function always evolves unitarily and never collapses.
- domain assumption A super-observer can undo a measurement by applying the inverse unitary interaction.
- domain assumption Absoluteness of Observed Events (AOE): outcomes of measurements are facts true for all observers.
- ad hoc to paper Any communication between two observers is itself a measurement of one observer by the other, so observers can never observe a disagreement.
- standard math Born rule and the standard Hilbert-space probability calculus applied to the Hardy state.
invented entities (1)
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Observer perception as a selection of one component of the superposed state (Convivial Solipsism)
Cite this review
Pith. "Pith review of Are Events Absolute?." pith.science (2026). https://pith.science/paper/V4QKE2DU
@misc{pith2026250714672,
author = {Pith},
title = {Pith review of: Are Events Absolute?},
year = {2026},
howpublished = {\url{https://pith.science/paper/V4QKE2DU}},
note = {Machine review of arXiv:2507.14672}
}
read the original abstract
The Wigner's Friend thought experiment stands as one of the most intellectually provocative and challenging conceptual puzzles in quantum mechanics. It compels us to confront profound questions concerning the fundamental nature of reality, the very act of observation, and the possible role that consciousness might play within the quantum measurement process. This article gives a general presentation, beginning with Eugene Wigner's seminal proposal of the original thought experiment. In this paper, we explore its initial implications, which shook the foundations of classical physics, and then progress to an examination of the recent theoretical advancements and the ingenious extended versions of the experiment. The recent versions seem to imply that it is no more possible to consider events as absolute.
Reference graph
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Reviewed August 6, 2026 · model on record in the stance chip above.
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