 How many individuals should be entrusted with a given decision? Epistemically speaking, what matters is how the correctness or quality of decisions depends on the number of participants, for instance, how the correctness of jury verdicts (“innocent” or “guilty”) depends on jury size, how the quality of parliamentary decisions depends on parliament size, how the quality of election outcomes depends on the size of the electorate, or how the quality of expert advice depends on the size of the advisory body. Jury theorems address this problem. Their perspective is epistemic rather than procedural: the sole aim is to reach “good” or “correct” decisions by an external standard rather than to respect individual participation rights or ensure democratically legitimate decisions. The reliance on correctness facts is the central philosophical commitment of jury theorems (see  Section 4.1).