At least since Bentham there has been a strong and vocal critique of exclusionary rules in evidence law. This critique holds that all relevant evidence should be allowed to be considered by the trier of fact. Many replies to this critique admit its central thrust, claiming instead that exclusions are needed only for public policy reasons or to combat inevitable prejudices. The critique has had sufficient sway that judges routinely cast aside many exclusionary rules and principles when deciding bench trials. I argue that contextualist epistemology provides a justification for exclusionary rules against Benthamite antinomianism in that the law has an interest in resisting shifts of context away from a range anchored by the standard of proof. Much otherwise relevant evidence can shift the standards for knowledge attributions (by triers of fact to themselves or to witnesses) away from that anchor, and hence rules excluding it are justified.