Wigner’s friend thought experiment
E98263
foundational quantum mechanics scenario
interpretation-of-quantum-mechanics problem
philosophy of physics concept
thought experiment
Wigner’s friend thought experiment is a foundational quantum mechanics scenario that explores the role of observers and consciousness in measurement by considering how different observers can assign conflicting quantum states to the same system.
All labels observed (5)
| Label | Occurrences |
|---|---|
| Wigner’s friend thought experiment canonical | 3 |
| Schrödinger's cat | 1 |
| Wigner's friend thought experiment | 1 |
| Wigner’s friend | 1 |
| Wigner’s friend paradox | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T818203 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Wigner’s friend thought experiment Context triple: [Eugene Wigner, knownFor, Wigner’s friend thought experiment]
-
A.
Maxwell's demon thought experiment
Maxwell's demon thought experiment is a famous conceptual scenario in thermodynamics that imagines an intelligent being seemingly violating the second law by sorting fast and slow gas molecules without expending energy.
-
B.
Bohr–Einstein debates
The Bohr–Einstein debates were a series of famous early 20th-century discussions between Niels Bohr and Albert Einstein about the foundations and interpretation of quantum mechanics, particularly concerning determinism, realism, and the completeness of the theory.
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C.
Super-many-time theory of quantum mechanics
The Super-many-time theory of quantum mechanics is a relativistic generalization of quantum mechanics that introduces multiple time variables to consistently describe interacting quantum fields in different reference frames.
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D.
Born rule in quantum mechanics
The Born rule in quantum mechanics is the fundamental postulate that connects a system’s wavefunction to experimentally observed probabilities by stating that measurement outcomes occur with probabilities given by the squared magnitude of the wavefunction’s amplitudes.
-
E.
Mathematical Foundations of Quantum Mechanics
Mathematical Foundations of Quantum Mechanics is John von Neumann’s landmark 1932 treatise that rigorously formulates quantum theory using functional analysis and operator theory on Hilbert spaces.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Wigner’s friend thought experiment Target entity description: Wigner’s friend thought experiment is a foundational quantum mechanics scenario that explores the role of observers and consciousness in measurement by considering how different observers can assign conflicting quantum states to the same system.
-
A.
Maxwell's demon thought experiment
Maxwell's demon thought experiment is a famous conceptual scenario in thermodynamics that imagines an intelligent being seemingly violating the second law by sorting fast and slow gas molecules without expending energy.
-
B.
Bohr–Einstein debates
The Bohr–Einstein debates were a series of famous early 20th-century discussions between Niels Bohr and Albert Einstein about the foundations and interpretation of quantum mechanics, particularly concerning determinism, realism, and the completeness of the theory.
-
C.
Super-many-time theory of quantum mechanics
The Super-many-time theory of quantum mechanics is a relativistic generalization of quantum mechanics that introduces multiple time variables to consistently describe interacting quantum fields in different reference frames.
-
D.
Born rule in quantum mechanics
The Born rule in quantum mechanics is the fundamental postulate that connects a system’s wavefunction to experimentally observed probabilities by stating that measurement outcomes occur with probabilities given by the squared magnitude of the wavefunction’s amplitudes.
-
E.
Mathematical Foundations of Quantum Mechanics
Mathematical Foundations of Quantum Mechanics is John von Neumann’s landmark 1932 treatise that rigorously formulates quantum theory using functional analysis and operator theory on Hilbert spaces.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
foundational quantum mechanics scenario
ⓘ
interpretation-of-quantum-mechanics problem ⓘ philosophy of physics concept ⓘ thought experiment ⓘ |
| addresses |
objectivity of measurement outcomes
ⓘ
observer relativity of quantum states ⓘ quantum measurement problem ⓘ |
| coreIdea |
different observers can assign different quantum states to the same physical system
ⓘ
friend observes a definite outcome while Wigner may still assign a superposed state ⓘ tension between unitary evolution and collapse postulate ⓘ |
| field |
foundations of quantum mechanics
ⓘ
philosophy of physics ⓘ quantum mechanics ⓘ |
| hasAuthor | Eugene Wigner ⓘ |
| hasInterpretationImplicationsFor |
collapse theories
ⓘ
hidden-variable theories ⓘ objective collapse models ⓘ subjective Bayesian interpretations ⓘ |
| historicalPeriod | 20th century ⓘ |
| involvesConcept |
conscious observer
ⓘ
measurement outcome ⓘ observer-relative state assignment ⓘ superposition ⓘ unitary evolution ⓘ wave function collapse ⓘ |
| involvesEntity |
Eugene Wigner
ⓘ
surface form:
Wigner
Wigner’s friend thought experiment self-linksurface differs ⓘ
surface form:
Wigner’s friend
laboratory isolated from Wigner ⓘ quantum system in a superposition ⓘ |
| mainTheme |
consciousness and quantum measurement
ⓘ
measurement problem in quantum mechanics ⓘ observer-dependent quantum states ⓘ role of observers in quantum measurement ⓘ |
| namedAfter | Eugene Wigner ⓘ |
| proposes | consciousness may play a role in wave function collapse ⓘ |
| questionRaised |
whether all observers must agree on a single set of facts
ⓘ
whether consciousness is necessary to define measurement outcomes ⓘ whether quantum mechanics is universally valid for observers themselves ⓘ |
| relatedTo |
Copenhagen interpretation of quantum mechanics
ⓘ
surface form:
Copenhagen interpretation
Everett many-worlds interpretation ⓘ Frauchiger–Renner paradox ⓘ QBism ⓘ Schrödinger's cat thought experiment ⓘ
surface form:
Schrödinger’s cat
relational quantum mechanics ⓘ |
| usedInDebatesOn |
consistency of quantum theory for multiple observers
ⓘ
objectivity vs subjectivity of quantum states ⓘ role of consciousness in physics ⓘ status of the wave function ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Wigner’s friend thought experiment Description of subject: Wigner’s friend thought experiment is a foundational quantum mechanics scenario that explores the role of observers and consciousness in measurement by considering how different observers can assign conflicting quantum states to the same system.
Referenced by (7)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Wigner’s friend paradox
this entity surface form:
Schrödinger's cat
Wigner’s friend thought experiment
→
involvesEntity
→
Wigner’s friend thought experiment
self-linksurface differs
ⓘ
this entity surface form:
Wigner’s friend
this entity surface form:
Wigner's friend thought experiment