Quantum mechanics is inconsistent with the idea that measurement outcomes are determined by hidden variables assigning definite, context-independent values to all observables simultaneously. Proved by Simon Kochen and Ernst Specker, it is a foundational no-go theorem about the interpretation of quantum mechanics, complementary to Bell's theorem.
Facts
StatementFor a Hilbert space of dimension three or greater, no function can assign a definite 0 or 1 value to every projection operator consistent with the sum rule for every orthogonal set of projections, ruling out any non-contextual hidden variable model of quantum mechanics. Kochen and Specker gave an explicit finite set of state vectors realizing this contradiction in 1967; a related no-go result was proved independently by John Bell in 1966. 1 Classification
Statement Form Connections
Has Statement Form
Entity-backed identity for the statement-form enum value this theorem already carries, resolved to a mathematics concept by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The statement-form fact itself stays on the theorem unchanged.
In Branch
Sources
1. Kochen-Specker Theorem (Wikipedia)
Wikimedia Foundationlead paragraph, first sentenceQuote, lead paragraph, first sentence
In quantum mechanics, the Kochen-Specker (KS) theorem, also known as the Bell-KS theorem, is a "no-go" theorem proved by John S. Bell in 1966 and by Simon B. Kochen and Ernst Specker in 1967.
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