Why Quantum Contextuality and Measurement Order Dependence Are the Same Phenomenon

Quantum contextuality and measurement order dependence are usually treated as distinct foundational problems. Contextuality is formulated as a logical obstruction to noncontextual value assignment, while order dependence is treated as a dynamical effect of sequential measurement. We show that these two phenomena arise from the same structural source. Within Modal Triplet Theory, each operational measurement context induces a context-dependent reduced dynamics, admissible domain, and associated basin atlas on the reduced state space. Contextuality corresponds to the impossibility of constructing a single global admissible basin assignment compatible with all contexts. Measurement order dependence is the dynamical manifestation of the same obstruction: sequential enforcement of incompatible basin atlases yields history-dependent outcome selection with positive probability. We prove an equivalence theorem establishing that contextuality and order dependence are two shadows—static and dynamical—of the same incompatibility. The framework aligns with Kochen–Specker theorems, contextuality inequalities, weak measurements, and sequential measurement experiments, while remaining consistent with projection-based outcome selection and the basin-measure reconstruction of the Born rule.