Multiple Juries: An Epistemic Complementarity Account

Current single jury systems use jury deliberation to generate accurate verdicts (for criminal and civil juries) or policy decisions and recommendations (for citizen juries). However, the evidence concerning the epistemic reliability of jury deliberation is mixed. One of the main problems that underlines their mixed epistemic credentials is that single deliberative juries tend to be relatively large, which encourages free-riding: In large deliberative juries, it might be more rational for jurors to simply repeat what other jurors say rather than form independent judgements. Some theorists have argued that countering epistemic free-riding requires eliminating or suspending jury deliberation. In this paper, we argue that neither elimination nor suspension are necessary to counter epistemic free-riding, and also argue that they squander the epistemic benefits of jury diversity. Specifically, we argue that epistemic free-riding can be better countered by replacing existing single jury systems with multiple jury systems. On our account, a multiple jury system would consist in a composite jury that includes multiple (smaller) component deliberative juries whose decisions are aggregated following a majority or super-majority rule. Adequately designed, a multiple jury system would be both deliberatively justified (by tapping into the benefits of jury diversity and the interactions between jurors at the component jury level) and aggregatively justified (by tapping into the additive benefits of the ‘wisdom of the crowds’ at the composite jury level). Thus construed, a multiple jury system capitalizes on the epistemic complementarity between deliberation and aggregation by tracking epistemic diversity and independence, while at the same time containing the risk of epistemic free-riding. We discuss whether, and to what extent, epistemic complementarity can be satisfied across different types of juries (criminal juries, civil juries and citizen juries).