URB #462 — The Bayesian Case Against Physicalist Dogmatism: Why Certainty Is Not Required for Open-Mindedness

URB #461 demonstrated that physicalism's three central pillars — physical causal closure, the dismissibility of all anomalous evidence, and the essential completeness of current physics — each carry an impossible burden of proof that physicalists have not met. This paper advances a complementary and independently decisive argument: **even granting physicalism a generous initial credence, no honest Bayesian who has examined the available evidence can rationally maintain confidence greater than 90–95% in physicalism.** The argument does not require proving that PSI is real, that non-physical causation exists, or that physicalism is probably false. It requires only that the accumulated evidence — meta-analyses of PSI research, persistent explanatory gaps, the non-physicalist convictions of genuinely elite scientists and mathematicians, and the repeated historical falsification of "essentially complete" physics claims — constitutes a non-negligible update signal that any rational posterior probability must absorb. A person who starts at 90% confidence in physicalism and refuses to move after encountering this evidence is not doing Bayesian inference. Their prior is functionally 1.0 — a certainty that no evidence could disturb. That is not skepticism. That is dogmatism dressed in probabilistic language. The paper formalizes six connected arguments: (1) what a rational Bayesian prior for physicalism looks like before examining evidence; (2) the evidential weight of high-profile non-physicalists whose scientific credentials are beyond question; (3) the open-mindedness floor — the minimum degree of uncertainty that any honest reasoner must maintain given the available evidence; (4) the diagnostic for pseudo-Bayesian dogmatism; (5) the evidential contribution of PSI meta-analyses across multiple independent research traditions; and (6) why the modest claim ("physicalism cannot rationally be held with >90–95% confidence") is both defensible and sufficient to transform the intellectual landscape. Absolute certainty is not required to exit dogmatism. Open-mindedness is not a concession — it is the only epistemically honest position available.