The Re-Derivation Test: _An Epistemic Discipline for Beliefs Maintained by Their Own History_

This paper formalizes the re-derivation test as a distinct procedural epistemic discipline — fifth relative to the four comparator disciplines named here (Bayesian updating, reflective equilibrium, Popperian falsification, and Cartesian methodic doubt), not an exhaustive taxonomy of epistemology. The test asks whether a believer's present endorsement of a proposition is reconstructible from current evidence once the evidential force of already endorsing it is removed. I distinguish two forms from the outset: solo re-derivation, the operation as the agent performs it on themselves; and witnessed re-derivation — the framework's mature institutional form, not a remedial supplement — performed in the recorded presence of an external party with authority to challenge the bracketing. Both forms belong to the framework from the start. After defining the test and distinguishing it from adjacent disciplines (including standpoint epistemology, adversarial collaboration, debiasing, and defeater theory), I develop applications in peer review, judicial precedent, scientific paradigm maintenance, AI alignment audits, and the trading discipline that originated the test. The principal failure mode — re-derivation that recovers the same conclusion through fresh premises selected by the very commitment the test was meant to bracket — is what the witness condition is built to detect.