Free will theorem

The free will theorem, proven by John Conway and Simon Kochen in 2006, states that if human experimenters have free will in the minimal sense that their choices of measurement settings are not determined by the prior history of the universe, then elementary particles must also possess a corresponding form of free will. The theorem is not a metaphysical claim about consciousness but a mathematical consequence of the Kochen-Specker theorem and the non-locality of quantum mechanics.

By showing that determinism at the particle level is incompatible with the assumption that experimenters can freely choose what to measure, the theorem collapses the distinction between human agency and quantum indeterminacy. It raises profound questions for philosophy of mathematics, quantum foundations, and the determinism debate.