Core Rationality

A Dispositional Account of Evidence-Proportionate Credence Epistemology routinely evaluates belief, credence, and norms of revision, yet the term "rationality" often functions as a catch-all that conflates two importantly dierent phenomena: (i) an evidence-responsive orientation toward inquiry and (ii) mastery of sophisticated formal tools for representing uncertainty and argument. This paper introduces as a stipulative neologism for the first phenomenon-an epistemic disposition to maintain evidence-proportionate credence across time-and contrasts it with , understood as technical competence with advanced methods (e.g., probability theory, Bayesian modeling, decision theory, and formal logic). The central thesis is that separating these notions fills a conceptual lacuna: it explains how agents can exhibit high technical competence while remaining systematically insensitive to counterevidence, and conversely how agents with limited formal training can nonetheless display robust evidential responsiveness. After presenting the definitions and motivating their independence, the paper situates core rationality within evidentialist supervenience theses and Bayesian credence norms, clarifies what "proportionate to evidence" can mean without requiring precise numerical assignments, and addresses objections from epistemic permissivism and from idealization worries about Bayesian norms. The final section sketches how the core/deep distinction can support a tractable research program for epistemic diagnosis and improvement by treating evidence-responsiveness as a separable target of assessment distinct from formal proficiency.