Epistemic Humility as Fiduciary Obligation: Entrusted Discretion and Responsibility for Belief

This article argues that fiduciary obligations include epistemic duties governing how entrusted discretion is exercised under conditions of dependency and authority—specifically, how fiduciaries form, sustain, and revise the beliefs that structure their discretionary judgment. While legal doctrine extensively regulates fiduciary conduct, conflicts of interest, and outcomes, it leaves the epistemic posture of fiduciaries under-theorised, despite the fact that fiduciary judgment is necessarily belief-mediated. Drawing on fiduciary theory, legal philosophy, and accounts of responsibility for belief, the article develops a role-relative conception of epistemic humility as a fiduciary obligation rather than an intellectual virtue. It shows how epistemic responsibility can attach without presupposing voluntary control over belief or collapsing into tort-based standards of harm and causation. Situating epistemic duties within the justificatory structure of fiduciary law itself, the article builds on accounts of loyalty as a condition of legitimate discretion and breach as the violation of beneficiaries’ justified expectations. It further draws on Fuller’s internal morality of governance to explain why epistemic discipline is internal to lawful fiduciary authority rather than an ethical overlay. Finally, it distinguishes fiduciary epistemic responsibility from power-based accounts of institutional epistemic governance and explains how epistemic failures can constitute fiduciary wrongs independently of compensable loss.