 The formal work on judgment aggregation stemmed from the “doctrinal paradox” in the jurisprudence literature (Kornhauser and Sager 1986, 1993, 2004; Kornhauser 1992). The paradox shows that judges may face a real danger of falling into collective irrationality when trying to reach a common and justified verdict. Despite the recent birth of the discipline, structurally similar problems seemed to have been first pointed out by Poisson in 1837 (as pointed out in Elster 2013), and later noted by the Italian legal theorist Vacca in 1921 (see Spector 2009).