The law requires criminal guilt to be proved beyond a reasonable doubt. There are two different approaches to construing this legal rule. On an epistemic approach, the rule is construed in terms of justified belief or knowledge; on a probabilistic approach, the rule is construed in terms of satisfying a probabilistic threshold. An epistemic construction of the rule has this advantage over a probabilistic construction: the former can while the latter cannot excuse the state from blame for a false conviction. This claim rests on an understanding of legal rules, legal justification for a finding of guilt and the central purpose of a criminal trial.