# John Stewart Bell Northern Irish physicist at CERN who proved in 1964 that local hidden-variable theories and [[Quantum Mechanics]] make different experimental predictions, converting a thirty-year philosophical dispute into a measurable question. See Bell's Theorem. Bell also identified the flaw in [[John von Neumann]]'s 1932 impossibility proof, writing that it was not merely false but foolish. He did his foundational work largely outside his official duties, at a time when quantum foundations was a reliable way to damage a physics career. The experiments confirming his theorem won the 2022 Nobel Prize; Bell died in 1990.