🤖 AI Summary
This work investigates the foundational assumption that observational symmetry implies causal structure symmetry. The authors construct a ternary binary probability distribution generated by three classical random sources and, under relaxed classical physical constraints—permitting generalized physical sources—rigorously prove the logical incompatibility among source homogeneity, relativistic causality, and target correlation. This result constitutes the first rigorous refutation of the intuitive principle that observational symmetry necessarily admits a symmetric causal explanation, thereby exposing a fundamental limitation of symmetry-based reasoning in causal modeling. It establishes an inescapable theoretical boundary for causal discovery in Bell-type networks and yields a novel necessary condition for the identifiability of causal structure.
📝 Abstract
Inferring causal models from observed correlations is a challenging task, crucial to many areas of science. In order to alleviate the effort, it is important to know whether symmetries in the observations correspond to symmetries in the underlying realization. Via an explicit example, we answer this question in the negative. We use a tripartite probability distribution over binary events that is realized by using three (different) independent sources of classical randomness. We prove that even removing the condition that the sources distribute systems described by classical physics, the requirements that i) the sources distribute the same physical systems, ii) these physical systems respect relativistic causality, and iii) the correlations are the observed ones, are incompatible.