Evidence record

What does quantum mechanics mean?

Every sentence on the exploration belongs to at least one claim below. Each says what kind of statement it is, what it rests on, what the evidence does not establish, and how far it was checked. Nothing here is a score, and none of it is a verdict on a belief or a theory.

Last checked 24 September 2026.

A judgement, not a fact: 10
Source checked: 48

If something here is wrong, misquoted, out of date or unfair, write to support@unknownoceans.com and give the claim number, which does not change.

What the question takes for granted

A question about what a well-confirmed theory describes. The predictions are not in dispute; the reading of them is, and surveys of the people who work on it find no majority for any one.

Quantum mechanics means something beyond its predictions
Contested
Instrumentalist and some epistemic views hold that the theory is a tool for expectations and there is nothing further to mean; the question takes one side of that.
The theory’s predictions are agreed and confirmed
Established
Every account in the poll is consistent with observation; collapse models differ only in experiments not yet done.
Experiment could decide between the readings
Open
Only for accounts that change the predictions, such as collapse models; the others are built to agree with the standard theory.

How the question is labelled

Claim: The theory that works and is not understood

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s summary of its own finding: the predictions succeed (claim 3) and there is no agreed account of what they describe (claims 4 and 19).

Claim 1 · checked 24 September 2026 · AI-assisted audit

Claim: Meaning

Kind: Framing. Signposting. It asserts nothing a source could check.

The question

Claim: Physicists agree on every prediction the theory makes and disagree about what it says.

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

Supports
Physicists should revel in the diversity of ways to understand quantum mechanicsparagraph 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: Everyone agrees that the mathematical framework of quantum mechanics is peerless at predicting the results of experiments exploring the subatomic world.
Supports
Physicists should revel in the diversity of ways to understand quantum mechanicsparagraph 3
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: Quantum mechanics lets researchers agree with extreme precision on the expected outcomes of observations.
Supports
Philosophical Issues in Quantum Theorysection 4.5
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: All of the above-mentioned approaches are consistent with observation.
Supports
A snapshot of foundational attitudes toward quantum mechanicsabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: the foundations of quantum mechanics themselves remain hotly debated in the scientific community, and no consensus on essential questions has been reached

What this does not establish

“Every prediction” is the standard theory’s. Collapse models are the exception the page itself discusses: they predict slight departures in experiments not yet done (claim 49).

Later work looked for

Crossref, 2013 on, "quantum foundations survey": the Nature survey and editorial of 2025 describe the same agreement on predictions and disagreement on meaning; nothing that changes it.

Claim 3 · checked 24 September 2026 · AI-assisted audit

Claim: Two surveys, fourteen years apart, found no majority for any interpretation.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 12 and commentary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: What is your favorite interpretation of quantum mechanics? ... Copenhagen: 42% ... The Copenhagen interpretation still reigns supreme here
Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: held in July 2011 at the International Academy Traunkirchen, Austria
Supports
Nature quantum mechanics survey: full results datacolumn "Favoured overall interpretation of quantum theory"
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: Favoured overall interpretation of quantum theory
Counted from the published data: 397 of the 1,101 answers chose the Copenhagen interpretation, the most chosen; 183 chose epistemic or information-based approaches and 165 Everett, many-worlds or consistent histories.
Supports
Nature quantum mechanics survey: methodologyResults and data cleaning
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: this gave 1,101 respondents, implying a (usable) response rate of about 7%
Supports
Physicists should revel in the diversity of ways to understand quantum mechanicsparagraph 5
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: The responses reveal that there is little or no consensus on questions about whether a particle really can exist in two places at once, whether there are multiple universes

What this does not establish

The two samples differ: 33 participants at one conference in 2011, and 1,101 researchers who answered a cold e-mail in 2025. The 2011 poll allowed several answers per question.

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the Nature survey of 2025 (1,101 usable responses, the largest of its kind per Nature’s editorial) again found no majority, Copenhagen leading at 36 per cent in its published data; page updated to report it.

Corrected

24 September 2026. Previously: “A poll of them found no majority for any answer.” Wrong as written: several answers in the 2011 poll did take a majority (58 per cent on Question 14, 64 on Question 6). No interpretation did. A 2025 survey by Nature more than thirty times the size now exists and found the same, so it is reported.

Claim 4 · checked 24 September 2026 · AI-assisted audit

Claim: Thirty-three physicists, philosophers and mathematicians at a foundations conference were polled on what their own theory is about, and no interpretation took a majority.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: we present the results of a poll carried out among 33 participants of a conference on the foundations of quantum mechanics
Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: A total of 33 people turned in their completed questionnaires; of those, 27 stated their main academic affiliation as physics, 5 as philosophy, and 3 as mathematics
Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 12 and commentary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: What is your favorite interpretation of quantum mechanics? ... Copenhagen: 42% ... The Copenhagen interpretation still reigns supreme here
Context
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: We permitted multiple answers per question to be checked

What this does not establish

Some respondents gave more than one field; 27 named physics. Several answers could be checked per question, so the shares sum to more than 100.

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Corrected

24 September 2026. Previously: “and no answer took a majority.” Several answers took a majority on other questions (58 per cent on Question 14). The finding is about interpretations.

Claim 5 · checked 24 September 2026 · AI-assisted audit

Claim: A survey of more than a thousand researchers in 2025 found the same.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
Nature quantum mechanics survey: methodologyResults and data cleaning
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: this gave 1,101 respondents, implying a (usable) response rate of about 7%
Supports
Nature quantum mechanics survey: full results datacolumn "Favoured overall interpretation of quantum theory"
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: Favoured overall interpretation of quantum theory
Counted from the published data: 397 of the 1,101 answers chose the Copenhagen interpretation, the most chosen; 183 chose epistemic or information-based approaches and 165 Everett, many-worlds or consistent histories.
Supports
Physicists should revel in the diversity of ways to understand quantum mechanicsparagraph 5
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: Nature’s news team conducted the largest-ever survey asking quantum physicists about the foundations of their discipline.

What this does not establish

Respondents were lead authors of recent quantum papers, plus attendees of one conference, who chose to answer; Nature says those who replied are likely enriched in researchers who care about the issue.

Later work looked for

Corrected

24 September 2026. Previously: “” Added: a far larger survey post-dates the 2011 poll and is needed for the page to be current.

Claim 6 · checked 24 September 2026 · AI-assisted audit

Claim: Some candidate theories have been ruled out by measurement,

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresmain text, conclusion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Our observation of a loophole-free Bell inequality violation thus rules out all local realist ... theories that accept that the number generators timely produce a free random bit and that the outputs are final once recorded in the electronics.
Supports
Underground test of gravity-related wave function collapseabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: This rules out the natural parameter-free version of the
Supports
Collapse Theoriessection 7
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: Moreover, the so-called Diosi-Penrose model has been falsified experimentally (Donadi et al. 2021), at least in its simpler formulation.

What this does not establish

What was ruled out is a class of local realist theories (on the Bell tests’ own conditions) and one form of one collapse model, not an interpretation on the poll’s list.

Later work looked for

Crossref, 2016 on, "loophole-free Bell inequality violation": later loophole-free tests and reviews confirm the violation; none removes the setting-independence assumption; nothing changes it.

Corrected

24 September 2026. Previously: “Some candidate theories have since been ruled out by measurement,” "Since" was left pointing at nothing once the 2025 survey sentence came first.

Claim 7 · checked 24 September 2026 · AI-assisted audit

Claim: which makes this a scientific dispute rather than only a philosophical one.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 7 and 49: some candidates make different predictions and can be tested.

Claim 8 · checked 24 September 2026 · AI-assisted audit

Claim: What is left includes accounts built to make identical predictions, which no experiment can tell apart.

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

Supports
Philosophical Issues in Quantum Theorysection 4.5
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: Extant hidden-variables theories reproduce the quantum probabilities
Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 14, commentary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: In the absence of empirical differences between the interpretations, it is only natural to conclude that one’s decision which interpretation to adopt will be influenced by personal preferences and beliefs.
Supports
Philosophical Issues in Quantum Theorysection 4.5
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: collapse theories have the intriguing feature of reproducing very close approximations to quantum probabilities for all experiments that have been performed so far but departing from the quantum probabilities for other conceivable experiments. This permits, in principle, an empirical discrimination

What this does not establish

Collapse models are among what is left and can in principle be told apart (claim 49).

Later work looked for

How the accounts are constructed; not a finding later work revises.

Corrected

24 September 2026. Previously: “What is left are the ones nobody knows how to tell apart.” Overstated: collapse models survive and do make testable predictions, as the page itself says. The encyclopedia distinguishes the ones that reproduce the quantum probabilities exactly.

Claim 9 · checked 24 September 2026 · AI-assisted audit

Claim: In 2011, at a conference on the foundations of quantum mechanics, thirty-three of the people who work on them were asked what they take their theory to be about.

Kind: Historical claim. A statement about the past that historical evidence can test.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: held in July 2011 at the International Academy Traunkirchen, Austria
Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: we present the results of a poll carried out among 33 participants of a conference on the foundations of quantum mechanics

Claim 10 · checked 24 September 2026 · AI-assisted audit

Claim: The largest bloc was around two fifths, and two fifths is not a majority.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 12
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: What is your favorite interpretation of quantum mechanics? ... Copenhagen: 42%
Context
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: We permitted multiple answers per question to be checked

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Claim 11 · checked 24 September 2026 · AI-assisted audit

Claim: A poll is a weak instrument and the authors said so themselves.

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: our poll cannot claim to be representative of the communities at large
Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: the multiple-choice format can sometimes obliterate the all-important nuances

Claim 12 · checked 24 September 2026 · AI-assisted audit

Claim: A survey more than thirty times the size, in 2025, found no majority either,

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

1,101 usable answers against 33.

Supports
Nature quantum mechanics survey: methodologyResults and data cleaning
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: this gave 1,101 respondents, implying a (usable) response rate of about 7%
Supports
Nature quantum mechanics survey: full results datacolumn "Favoured overall interpretation of quantum theory"
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: Favoured overall interpretation of quantum theory
Counted from the published data: 397 of the 1,101 answers chose the Copenhagen interpretation, the most chosen; 183 chose epistemic or information-based approaches and 165 Everett, many-worlds or consistent histories.

Later work looked for

Corrected

24 September 2026. Previously: “It is also the most comprehensive count anyone has made,” Out of date: the poll’s authors called it the most comprehensive "to our knowledge" in 2013; Nature’s 2025 survey of 1,101 researchers is, in Nature’s words, the largest ever.

Claim 13 · checked 24 September 2026 · AI-assisted audit

Claim: and what both count is not a gap in the evidence.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claim 9: many of the accounts make the same predictions, so the split is not over data.

Corrected

24 September 2026. Previously: “and what it counts is not a gap in the evidence.” Now refers to both surveys.

Claim 14 · checked 24 September 2026 · AI-assisted audit

Claim: It is a disagreement among people who get the same numbers out of the same equations.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The editorial’s point that the theory lets researchers agree on expected outcomes, and the poll authors’ remark on the absence of empirical differences.

Supports
Physicists should revel in the diversity of ways to understand quantum mechanicsparagraph 3
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: Quantum mechanics lets researchers agree with extreme precision on the expected outcomes of observations.
Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 14, commentary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: In the absence of empirical differences between the interpretations, it is only natural to conclude that one’s decision which interpretation to adopt will be influenced by personal preferences and beliefs.

Claim 15 · checked 24 September 2026 · AI-assisted audit

What is agreed

Claim: What is agreed

Kind: Framing. Signposting. It asserts nothing a source could check.

The disagreement is real and was counted

Claim: The disagreement is real and was counted

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 12
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: What is your favorite interpretation of quantum mechanics? ... Copenhagen: 42%
Supports
Nature quantum mechanics survey: full results datacolumn "Favoured overall interpretation of quantum theory"
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: Favoured overall interpretation of quantum theory
Counted from the published data: 397 of the 1,101 answers chose the Copenhagen interpretation, the most chosen; 183 chose epistemic or information-based approaches and 165 Everett, many-worlds or consistent histories.

Later work looked for

Claim 17 · checked 24 September 2026 · AI-assisted audit

Claim: At a 2011 conference on the foundations of quantum mechanics, thirty-three participants were polled on what they believed.

Kind: Historical claim. A statement about the past that historical evidence can test.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: held in July 2011 at the International Academy Traunkirchen, Austria
Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: we present the results of a poll carried out among 33 participants of a conference on the foundations of quantum mechanics

Claim 18 · checked 24 September 2026 · AI-assisted audit

Claim: No interpretation held a majority.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 12
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: What is your favorite interpretation of quantum mechanics? ... Copenhagen: 42%

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Claim 19 · checked 24 September 2026 · AI-assisted audit

Claim: The most popular answer, the one associated with Copenhagen, took 42 per cent.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 12
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: What is your favorite interpretation of quantum mechanics? ... Copenhagen: 42%
Context
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: We permitted multiple answers per question to be checked
Context
Philosophical Issues in Quantum Theorysection 4.2.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: Readers should be aware that the term is not univocal, and that different authors might mean different things when speaking of the“Copenhagen interpretation.”

What this does not establish

The term “Copenhagen interpretation” is not univocal: different people mean different things by it.

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Claim 20 · checked 24 September 2026 · AI-assisted audit

Claim: Everett took 18 and information-based readings 24.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 12
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: d. Everett (many worlds and/or many minds): 18% e. Information-based/information-theoretical: 24%

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Claim 21 · checked 24 September 2026 · AI-assisted audit

Claim: Asked about the measurement problem itself, 27 per cent called it a pseudoproblem and 24 per cent called it a severe difficulty threatening the theory.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 5
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: a. A pseudoproblem: 27%
Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 5
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: d. A severe difficulty threatening quantum mechanics: 24%

What this does not establish

Other answers took more: 39 per cent said it is solved or will be solved in another way, 15 per cent by decoherence.

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Claim 22 · checked 24 September 2026 · AI-assisted audit

Claim: Asked how much the choice of interpretation is personal philosophical prejudice, 58 per cent said a lot.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 14
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: How much is the choice of interpretation a matter of personal philosophical prejudice? a. A lot: 58%

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Claim 23 · checked 24 September 2026 · AI-assisted audit

Claim: Thirty-three people at one conference is a small sample, and the authors said plainly that it cannot claim to be representative of the communities at large.

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: our poll cannot claim to be representative of the communities at large
Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: we present the results of a poll carried out among 33 participants of a conference on the foundations of quantum mechanics

Claim 24 · checked 24 September 2026 · AI-assisted audit

Claim: It was, to their knowledge, the most comprehensive poll of its kind at the time.

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

At the time of the paper, 2013; the next sentence reports the larger survey since.

Supports
A snapshot of foundational attitudes toward quantum mechanicssection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: it is to our knowledge the most comprehensive poll of quantum-foundational views ever conducted

Corrected

24 September 2026. Previously: “It remains the most comprehensive count anyone has made, and what it counts is a field that cannot agree.” Out of date: Nature’s 2025 survey drew 1,101 usable answers and is, in Nature’s words, the largest ever. The authors also claimed the record only "to our knowledge".

Claim 25 · checked 24 September 2026 · AI-assisted audit

Claim: In 2025 a survey by Nature drew 1,101 usable answers from researchers who work with quantum theory,

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
Nature quantum mechanics survey: methodologyResults and data cleaning
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: this gave 1,101 respondents, implying a (usable) response rate of about 7%
Supports
Nature quantum mechanics survey: methodologymethodology
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: It was e-mailed to 15,582 lead authors of relevant recent research papers
Supports
Physicists should revel in the diversity of ways to understand quantum mechanicsparagraph 5
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: Nature’s news team conducted the largest-ever survey asking quantum physicists about the foundations of their discipline.

What this does not establish

A response rate of about 7 per cent; Nature expects the respondents to be enriched in researchers who care about the question. Some 300 attendees of one conference were also invited.

Later work looked for

Corrected

24 September 2026. Previously: “” Added so the page reports the larger, later survey.

Claim 26 · checked 24 September 2026 · AI-assisted audit

Claim: and the Copenhagen reading again led without a majority, at 36 per cent.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

Supports
Nature quantum mechanics survey: full results datacolumn "Favoured overall interpretation of quantum theory"
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: Favoured overall interpretation of quantum theory
Counted from the published data: 397 of the 1,101 answers chose the Copenhagen interpretation, the most chosen; 183 chose epistemic or information-based approaches and 165 Everett, many-worlds or consistent histories.

What this does not establish

Nature’s options were worded differently from the 2011 poll’s, and one of them grouped many-worlds with consistent histories.

Later work looked for

Claim 27 · checked 24 September 2026 · AI-assisted audit

Claim: Two of the main positions

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: The wave function is knowledge

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

A label for epistemic and information-based views, which took 24 per cent in the 2011 poll.

Supports
Philosophical Issues in Quantum Theorysection 4.2.2
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: views of this sort have been advocated by physicists, including QBists, who hold that quantum states represent subjective or epistemic probabilities

Claim 29 · checked 24 September 2026 · AI-assisted audit

Claim: It describes what an observer can predict, not what exists

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
Philosophical Issues in Quantum Theorysection 4.2.2
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: quantum mechanics is a tool for coordinating our experience and for forming expectations about the outcomes of experiments
Supports
Quantum-Bayesian and Pragmatist Views of Quantum Theorysection 1.3
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: QBists avoid this problem by denying that a quantum state (even incompletely) describes the system to which it assigned.

Claim 30 · checked 24 September 2026 · AI-assisted audit

Claim: Collapse is an update of information, so there is nothing to explain

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
Quantum-Bayesian and Pragmatist Views of Quantum Theorysection 1.3
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: This represents no physical discontinuity associated with measurement, but merely reflects the agent’s updated epistemic state in the light of experience.

What this does not establish

This is the position’s own claim. Critics answer that the question moves rather than disappears (claim 32).

Claim 31 · checked 24 September 2026 · AI-assisted audit

Claim: Leaves the question of what the world is made of unanswered

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
Quantum-Bayesian and Pragmatist Views of Quantum Theorysection 2.3
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: In their view a user of quantum theory can’t appeal to a description of objective, physical quantum states in explaining the phenomena
Supports
Philosophical Issues in Quantum Theorysection 4.2
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: We include in the first category approaches that deny that a quantum state should be thought of as representing anything in reality at all.

Claim: The wave function is everything

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

A label for the Everett, or many-worlds, interpretation.

Supports
Many-Worlds Interpretation of Quantum Mechanicssection 1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: the ontology of the Universe is a quantum state evolving according to the Schrödinger equation or its relativistic generalization

Claim 33 · checked 24 September 2026 · AI-assisted audit

Claim: Nothing collapses; all outcomes occur in branches that stop interacting

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
Many-Worlds Interpretation of Quantum Mechanicssection 1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: every time a quantum experiment with different possible outcomes is performed, all outcomes are obtained, each in a different, newly created world
Supports
The Role of Decoherence in Quantum Mechanicssection 3
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: decoherence ... can be used to naturally identify stable (if branching) structures within the universal wave function
Qualifies
Many-Worlds Interpretation of Quantum Mechanicssection 6
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: These proposals remain strictly gedanken experiments, far beyond the reach of current or foreseeable technology, because they require observing interference between different worlds.

What this does not establish

In principle branches could still interfere; in practice it would take an interference experiment on a macroscopic body, far beyond present technology.

Claim 34 · checked 24 September 2026 · AI-assisted audit

Claim: The equations are taken literally with nothing added

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
Many-Worlds Interpretation of Quantum Mechanicssection 7.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: It retains all the laws of standard quantum theory but eliminates the collapse postulate
Qualifies
Many-Worlds Interpretation of Quantum Mechanicssection 7.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: they argue that this advantage is irrelevant, since the MWI postulates alone are not enough to explain our experience

What this does not establish

Some critics argue the equations alone do not connect to experience, so something must be added after all.

Claim 35 · checked 24 September 2026 · AI-assisted audit

Claim: The meaning of probability in a theory where everything happens is contested

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
Many-Worlds Interpretation of Quantum Mechanicssection 7.4
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: is arguably the most serious difficulty. How can probability exist if all possible outcomes occur?

Claim 36 · checked 24 September 2026 · AI-assisted audit

Some questions have been settled experimentally

Claim: Some questions have been settled experimentally

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresmain text, conclusion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Our observation of a loophole-free Bell inequality violation thus rules out all local realist ... theories that accept that the number generators timely produce a free random bit and that the outputs are final once recorded in the electronics.
Supports
Underground test of gravity-related wave function collapseabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: This rules out the natural parameter-free version of the

What this does not establish

Settled on each experiment’s own conditions: the Bell tests assume free setting choices (claim 38).

Later work looked for

Crossref, 2016 on, "loophole-free Bell inequality violation": later loophole-free tests and reviews confirm the violation; none removes the setting-independence assumption; nothing changes it.

Claim 37 · checked 24 September 2026 · AI-assisted audit

Claim: Bell tests rule out the class of theories in which particles carry their answers locally in advance, provided the choice of settings was not itself somehow fixed beforehand.

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresmain text, conclusion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Our observation of a loophole-free Bell inequality violation thus rules out all local realist ... theories that accept that the number generators timely produce a free random bit and that the outputs are final once recorded in the electronics.
Qualifies
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresmain text, conclusion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Strictly speaking, no Bell experiment can exclude the infinite number of conceivable local realist theories, because it is fundamentally impossible to prove when and where free random input bits and output values came into existence

What this does not establish

No Bell test can exclude every conceivable local theory, as the 2015 authors say. The result also assumes the outputs were final once recorded.

Claim: Interference experiments with larger and larger objects have pushed the boundary of where quantum behaviour stops, without finding it.

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Probing quantum mechanics with nanoparticle matter-wave interferometryabstract; Discussion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Over the years, this has been explored with a series of objects of increasing mass and complexity ... Observing matter-wave interference of the most massive objects to date reveals no breakdown of the quantum superposition principle related to mass or size alone.
Supports
Probing quantum mechanics with nanoparticle matter-wave interferometryabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: We specifically demonstrate quantum interference of sodium nanoparticles, which can each contain more than 7,000 atoms at masses greater than 170,000 Da.
Supports
Schrödinger cat states of a 16-microgram mechanical oscillatormain text
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: observing state superpositions in massive objects is of key importance for exploring the validity range of quantum mechanics as we know it

Later work looked for

Crossref, 2019 on, "matter-wave interference" and "macroscopic superposition": Pedalino and others 2026 supersede the 2019 molecules the page called the record; page updated, consistent with "What actually happens when we look?".

Corrected

24 September 2026. Previously: “without finding it: the record stands at molecules of two thousand atoms.” The record sentence was out of date; see claim 40.

Claim 39 · checked 24 September 2026 · AI-assisted audit

Claim: The latest, in 2026, used sodium clusters of more than seven thousand atoms, and in 2023 the vibration of a sixteen-microgram crystal was put in superposition over a far shorter distance.

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Probing quantum mechanics with nanoparticle matter-wave interferometryabstract; Discussion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: We specifically demonstrate quantum interference of sodium nanoparticles, which can each contain more than 7,000 atoms at masses greater than 170,000 Da. ... with a 133 nm separation between the two locations
Supports
Schrödinger cat states of a 16-microgram mechanical oscillatorabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Here we demonstrate the preparation of a mechanical resonator with an effective mass of 16.2 micrograms in
Supports
Schrödinger cat states of a 16-microgram mechanical oscillatormain text
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: delocalized over a distance of 2.1 · 10⁻¹⁸ m
Notation restored: Exponent restored as the arXiv PDF (2211.00449v1) sets it, checked from the glyph positions with pdftotext -bbox, 2026-09-24. The text as extracted reads: delocalized over a distance of 2.1 · 10−18 m
Supports
Schrödinger cat states of a 16-microgram mechanical oscillatormain text, figure 1 caption
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: The inset shows the superposition of two opposite-phase oscillations of atoms in the crystal lattice.
Context
Quantum superposition of molecules beyond 25 kDaabstract
Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Physical systems · Experiment
The source reads: with masses beyond 25,000 Da and consisting of up to 2,000 atoms, by far the heaviest objects shown to exhibit matter-wave interference to date
The previous result the page cited as the record.

What this does not establish

Two different kinds of experiment: the clusters were delocalized by more than ten times their own diameter; the crystal’s vibration by about 2 × 10⁻¹⁸ metres. Each is one group’s result.

Later work looked for

Corrected

24 September 2026. Previously: “the record stands at molecules of two thousand atoms.” Out of date: the 2019 molecules (up to 2,000 atoms) were overtaken by sodium clusters of more than 7,000 atoms (Pedalino and others, Nature, 2026), and a 16.2-microgram oscillator was put in a superposition in 2023 (Bild and others, Science).

Claim 40 · checked 24 September 2026 · AI-assisted audit

Claim: So this is not a domain where nothing is decidable.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 38 and 52.

Claim 41 · checked 24 September 2026 · AI-assisted audit

Claim: Candidate theories do get killed by measurement,

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresmain text, conclusion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Our observation of a loophole-free Bell inequality violation thus rules out all local realist ... theories that accept that the number generators timely produce a free random bit and that the outputs are final once recorded in the electronics.
Supports
Underground test of gravity-related wave function collapseabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: This rules out the natural parameter-free version of the
Supports
Collapse Theoriessection 7
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: Moreover, the so-called Diosi-Penrose model has been falsified experimentally (Donadi et al. 2021), at least in its simpler formulation.

Later work looked for

Crossref, 2016 on, "loophole-free Bell inequality violation": later loophole-free tests and reviews confirm the violation; none removes the setting-independence assumption; nothing changes it.

Claim 42 · checked 24 September 2026 · AI-assisted audit

Claim: which is why the survivors are the ones that are hard to tell apart.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 42 and 53: what survives either matches the standard predictions exactly or departs from them only in experiments not yet done.

Claim 43 · checked 24 September 2026 · AI-assisted audit

Claim: What the Bell tests killed is not any of the interpretations on offer, though.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The interpretations in the poll either give up locality (as pilot-wave theory does), deny that measured values exist before measurement, or deny that one outcome occurs, so none is a local theory with pre-existing values.

Claim 44 · checked 24 September 2026 · AI-assisted audit

Claim: It is the wider class of local theories with pre-existing values,

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresmain text, conclusion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Our observation of a loophole-free Bell inequality violation thus rules out all local realist ... theories that accept that the number generators timely produce a free random bit and that the outputs are final once recorded in the electronics.
Qualifies
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresmain text, conclusion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Strictly speaking, no Bell experiment can exclude the infinite number of conceivable local realist theories, because it is fundamentally impossible to prove when and where free random input bits and output values came into existence

Later work looked for

Crossref, 2016 on, "loophole-free Bell inequality violation": later loophole-free tests and reviews confirm the violation; none removes the setting-independence assumption; nothing changes it.

Claim 45 · checked 24 September 2026 · AI-assisted audit

Claim: which none of them was.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

As for claim 44.

Claim 46 · checked 24 September 2026 · AI-assisted audit

What might be decided

Claim: What might be decided

Kind: Framing. Signposting. It asserts nothing a source could check.

Whether the difference is testable

Claim: Whether the difference is testable

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: Some proposals make different predictions.

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

Supports
Philosophical Issues in Quantum Theorysection 4.5
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: collapse theories have the intriguing feature of reproducing very close approximations to quantum probabilities for all experiments that have been performed so far but departing from the quantum probabilities for other conceivable experiments. This permits, in principle, an empirical discrimination

Later work looked for

SEP entry revised March 2022; Crossref, 2021 on, "collapse model tests": tests continue and the models remain distinguishable in principle; nothing changes it.

Claim 49 · checked 24 September 2026 · AI-assisted audit

Claim: Objective collapse models add a physical process that destroys superpositions in large systems,

Kind: What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review: Source checked. The cited passage was read, and it says this.

Supports
Collapse Theoriessection 5
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: the quantum predictions for microscopic systems remain fully valid while the embarrassing macroscopic superpositions in measurement-like situations are suppressed in very short times

What this does not establish

A proposal: no collapse process has been observed.

Claim 50 · checked 24 September 2026 · AI-assisted audit

Claim: and experiments are closing in on their parameters.

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Collapse Theoriessection 7
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: The importance of this class of experiments lies in the fact that–so far–they provide the strongest upper bounds on the collapse parameters
Supports
Collapse Theoriessection 7
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: experiments in which one might test the deviations from Standard Quantum Theory implied by Collapse Models, seems to have become more and more feasible
Supports
Underground test of gravity-related wave function collapseabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: This rules out the natural parameter-free version of the

Later work looked for

Crossref, 2021 on, "Diósi-Penrose model test" and "gravity-related collapse radiation": later work extends the model and proposes tests; nothing reverses the result. SEP "Collapse Theories" (revised September 2025) reports it the same way.

Claim 51 · checked 24 September 2026 · AI-assisted audit

Claim: One such model, the parameter-free version of the gravitational proposal of Diósi and Penrose, was ruled out in 2020 by a search under a mountain for the radiation it should have produced.

Kind: Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
Review: Source checked. The cited passage was read, and it says this.

Supports
Underground test of gravity-related wave function collapseabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: This rules out the natural parameter-free version of the
Supports
Underground test of gravity-related wave function collapseabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: resulting, if charged, in the emission of radiation. Here, we compute the radiation emission rate, which is faint but detectable.
Supports
Underground test of gravity-related wave function collapsemain text
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: characterized by a rock overburden
Supports
Collapse Theoriessection 7
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: Moreover, the so-called Diosi-Penrose model has been falsified experimentally (Donadi et al. 2021), at least in its simpler formulation.

What this does not establish

One experiment. Versions of the model with an adjustable size parameter survive. Published online in September 2020, in print in 2021.

Later work looked for

Claim 52 · checked 24 September 2026 · AI-assisted audit

Claim: Others make identical predictions by construction.

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

Supports
Philosophical Issues in Quantum Theorysection 4.5
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: Extant hidden-variables theories reproduce the quantum probabilities
Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 14, commentary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: In the absence of empirical differences between the interpretations, it is only natural to conclude that one’s decision which interpretation to adopt will be influenced by personal preferences and beliefs.

Later work looked for

How the accounts are constructed; not a finding later work revises.

Claim 53 · checked 24 September 2026 · AI-assisted audit

Claim: Between those, the choice is made on grounds of simplicity, of what one is willing to call real, and of taste,

Kind: What scholars argue. A report of what specialists argue, or where they disagree.
Review: Source checked. The cited passage was read, and it says this.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 14, commentary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: In the absence of empirical differences between the interpretations, it is only natural to conclude that one’s decision which interpretation to adopt will be influenced by personal preferences and beliefs.
Supports
Many-Worlds Interpretation of Quantum Mechanicssection 7.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: From this perspective, the MWI emerges as the most economical theory.

Claim 54 · checked 24 September 2026 · AI-assisted audit

Claim: which is not a word physicists enjoy using about physics.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s aside; the editorial and the poll authors both describe discomfort with the role of preference.

Context
Physicists should revel in the diversity of ways to understand quantum mechanicsparagraph 2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: Some scientists are embarrassed, 100 years after quantum theory was first formulated, by this inability to agree on a single narrative about the basic nature of reality
Context
A snapshot of foundational attitudes toward quantum mechanicsQuestion 14, commentary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: sometimes perceived as an ideological battle where the objectivity of the scientific enterprise succumbs to philosophical and personal preferences

Claim 55 · checked 24 September 2026 · AI-assisted audit

Claim: In the poll, the largest single answer on that point was that the choice is a lot a matter of personal philosophical prejudice.

Kind: Present-day figure. A count, survey or report finding, as the named source gives it.
Review: Source checked. The cited passage was read, and it says this.

58 per cent, a majority.

Supports
A snapshot of foundational attitudes toward quantum mechanicsQuestion 14
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes
The source reads: How much is the choice of interpretation a matter of personal philosophical prejudice? a. A lot: 58%

Later work looked for

Crossref, 2013 on, "survey physicists interpretation quantum mechanics": the 2011 figures are a record of that poll and cannot be revised; a larger survey in 2025 is now reported beside them.

Claim 56 · checked 24 September 2026 · AI-assisted audit

The measurement problem

Claim: The measurement problem

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: A century of perfect predictions and no agreement about what is being predicted.

Kind: This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review: A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Compresses claims 3 and 4: every experiment so far agrees with the theory, and there is no majority for any reading of it. "Perfect" means no confirmed failure, not unlimited precision.

Claim 58 · checked 24 September 2026 · AI-assisted audit

What happens at a measurement

Claim: What happens at a measurement

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: The equations describe smooth, reversible evolution.

Kind: What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review: Source checked. The cited passage was read, and it says this.

Supports
Quantum Mechanicssection 3
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: it is deterministic, which is to say that it takes the state of a system at one time into a unique state at any other, it is unitary

What this does not establish

Reversible because the evolution is unitary, a one-to-one map of states; this is the Schrödinger equation, not the collapse postulate.

Later work looked for

How the theory is formulated; not a finding later work revises.

Claim 60 · checked 24 September 2026 · AI-assisted audit

Claim: Observations produce one definite outcome.

Kind: Observation. Something measured or seen, as the named source reports it.
Review: Source checked. The cited passage was read, and it says this.

Supports
Philosophical Issues in Quantum Theorysection 4.2
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: our experience, according to which experimental outcome variables, such as pointer readings, always have definite values
Qualifies
Philosophical Issues in Quantum Theorysection 4.2
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: This is a misleading way of putting the issue
Context
Many-Worlds Interpretation of Quantum Mechanicssection 1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: all outcomes are obtained, each in a different, newly created world, even if we are only aware of the world with the outcome we have seen

Claim: Nothing in the theory says where one ends and the other begins, or what qualifies as an observation.

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

Supports
Quantum Mechanicssection 3
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: nobody has managed to say in a completely satisfactory way, in the terms provided by the theory, which contexts are measurement contexts

Later work looked for

SEP entry revised January 2025; the standard formulation has not changed.

Claim 62 · checked 24 September 2026 · AI-assisted audit

Claim: Decoherence explains why superpositions become unobservable very quickly in any system touching its environment,

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

Supports
The Role of Decoherence in Quantum Mechanicssection 1.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: This coherence length is reached after a microsecond of exposure to air, and suppression of interference on a length scale of ... is achieved already after a nanosecond.
Supports
The Role of Decoherence in Quantum Mechanicssection 2.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: while decoherence does explain why we do not observe superpositions of measurement results, it does not explain why we do observe measurement results in the first place.

What this does not establish

How fast depends on the system and its environment; the times quoted are for a speck of dust in air.

Later work looked for

Crossref, 2015 on, "decoherence measurement problem": nothing that changes the account; the SEP entry was revised in January 2025.

Claim 63 · checked 24 September 2026 · AI-assisted audit

Claim: which removes much of the mystery about why the world looks classical.

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

Supports
The Role of Decoherence in Quantum Mechanicssection 4.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: What seems very clear is that decoherence is crucial for the emergence of much of the macroscopic world around us
Qualifies
The Role of Decoherence in Quantum Mechanicssection 4.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: The detailed picture of the world that emerges from decoherence, however, is full of subtleties.

Later work looked for

Crossref, 2015 on, "decoherence measurement problem": nothing that changes the account; the SEP entry was revised in January 2025.

Claim 64 · checked 24 September 2026 · AI-assisted audit

Claim: It does not, on its own, explain why one outcome rather than another is the one that happened.

Kind: What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review: Source checked. The cited passage was read, and it says this.

The encyclopedia puts it as not explaining why measurements have results at all; which result, in a single world, is the same gap.

Supports
The Role of Decoherence in Quantum Mechanicssection 2.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: while decoherence does explain why we do not observe superpositions of measurement results, it does not explain why we do observe measurement results in the first place.
Supports
The Role of Decoherence in Quantum Mechanicssection 2.1
Cited · Link answered, 19 October 2026 · The cited passage was read, 24 September 2026 · Reference work
The source reads: decoherence as such does not provide a solution to the measurement problem, at least not unless it is combined with an appropriate foundational approach to the theory

Later work looked for

Crossref, 2015 on, "decoherence measurement problem": nothing that changes the account; the SEP entry was revised in January 2025.

Claim 65 · checked 24 September 2026 · AI-assisted audit

What was read

A snapshot of foundational attitudes toward quantum mechanicsSchlosshauer, Kofler and Zeilinger, Studies in History and Philosophy of Modern Physics · arXiv:1301.1069v1 (6 January 2013), the accepted text of the cited article; read in fullRead in full, 24 September 2026 · Copyright; quoted briefly
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresHensen and others, Nature · arXiv:1508.05949v1 (24 August 2015), the submitted manuscript of Nature 526, 682 to 686Read in full, 24 September 2026 · Copyright; quoted briefly
Quantum superposition of molecules beyond 25 kDaFein and colleagues, Nature Physics · Nature Physics 15, 1242 to 1245; abstract from the article page; full text paywalledAbstract only, 24 September 2026 · Copyright; quoted briefly
Probing quantum mechanics with nanoparticle matter-wave interferometryPedalino, Ramírez-Galindo, Ferstl, Hornberger, Arndt and Gerlich, Nature 649, pages 866 to 870 · Nature 649, 866 to 870, open-access article page; read abstract and main textRead in full, 24 September 2026 · CC BY 4.0
Schrödinger cat states of a 16-microgram mechanical oscillatorBild, Fadel, Yang, von Lüpke, Martin, Bruno and Chu, Science 380, pages 274 to 278 · arXiv:2211.00449v1 (1 November 2022); read abstract and main textRead in full, 24 September 2026 · Copyright; quoted brieflyPDF text extraction renders exponents inline ("10−18"); the excerpt keeps it as extracted, and the reader is shown the exponent restored.
Underground test of gravity-related wave function collapseDonadi and colleagues, Nature Physics · arXiv:2111.13490v1 (26 November 2021); read abstract and main textRead in full, 24 September 2026 · Copyright; quoted briefly
The Role of Decoherence in Quantum MechanicsStanford Encyclopedia of Philosophy · SEP, substantive revision 23 January 2025; read sections 1.1, 2.1, 3 and 4.1The cited passage was read, 24 September 2026 · Copyright; quoted briefly
Quantum MechanicsStanford Encyclopedia of Philosophy · SEP, substantive revision 18 January 2025; read section 3The cited passage was read, 24 September 2026 · Copyright; quoted briefly
Philosophical Issues in Quantum TheoryStanford Encyclopedia of Philosophy · SEP, substantive revision 23 March 2022; read sections 4.1, 4.2 and 4.5The cited passage was read, 24 September 2026 · Copyright; quoted briefly
Collapse TheoriesStanford Encyclopedia of Philosophy · SEP, substantive revision 30 September 2025; read the opening, the GRW section and section 7The cited passage was read, 24 September 2026 · Copyright; quoted briefly
Many-Worlds Interpretation of Quantum MechanicsStanford Encyclopedia of Philosophy · SEP, substantive revision 17 June 2026; read sections 1, 4, 6 and 7The cited passage was read, 24 September 2026 · Copyright; quoted briefly
Quantum-Bayesian and Pragmatist Views of Quantum TheoryStanford Encyclopedia of Philosophy · SEP, substantive revision 8 September 2026; read sections 1 and 2.3The cited passage was read, 24 September 2026 · Copyright; quoted briefly
Physicists should revel in the diversity of ways to understand quantum mechanicsEditorial, Nature 643, pages 1157 to 1158 · Nature 643, 1157 to 1158, nature.com article pageRead in full, 24 September 2026 · Copyright; quoted briefly
Nature quantum mechanics survey: methodologyNature, supplementary information to a news feature by Elizabeth Gibney, Nature 643, pages 1175 to 1179 · Three-page methodology PDF, supplementary information to Gibney, Nature 643, 1175 to 1179 (the news feature itself is paywalled and was not read)Read in full, 24 September 2026 · Copyright; quoted briefly
Nature quantum mechanics survey: full results dataNature, supplementary information to a news feature by Elizabeth Gibney, Nature 643, pages 1175 to 1179 · CSV of anonymized responses; the favoured-interpretation column was countedRead in full, 24 September 2026 · Copyright; quoted briefly