Dietrich, Franz and Spiekermann, Kai (2010): Epistemic democracy with defensible premises.

PDF
MPRA_paper_40135.pdf Download (325kB)  Preview 
Abstract
The contemporary theory of epistemic democracy often draws on the Condorcet Jury Theorem to formally justify the `wisdom of crowds'. But this theorem is inapplicable in its current form, since one of its premises  voter independence  is notoriously violated. This premise carries responsibility for the theorem's misleading conclusion that `large crowds are infallible'. We prove a more useful jury theorem: under defensible premises, `large crowds are fallible but better than small groups'. This theorem rehabilitates the importance of deliberation and education, which appear inessential in the classical jury framework. Our theorem is related to Ladha's (1993) seminal jury theorem for interchangeable (`indistinguishable') voters based on de Finetti's Theorem. We prove a more general and simpler version of such a theorem.
Item Type:  MPRA Paper 

Original Title:  Epistemic democracy with defensible premises 
Language:  English 
Keywords:  Condorcet Jury Theorem, dependence between voters, common causes, interchangeable voters, de Finetti's Theorem 
Subjects:  D  Microeconomics > D7  Analysis of Collective DecisionMaking > D71  Social Choice ; Clubs ; Committees ; Associations D  Microeconomics > D7  Analysis of Collective DecisionMaking > D70  General C  Mathematical and Quantitative Methods > C0  General D  Microeconomics > D8  Information, Knowledge, and Uncertainty 
Item ID:  40135 
Depositing User:  Franz Dietrich 
Date Deposited:  18 Jul 2012 20:49 
Last Modified:  05 Jan 2017 06:05 
References:  AustenSmith, D. & Banks, J. (1996), `Information Aggregation, Rationality, and the Condorcet Jury Theorem', American Political Science Review, 90, 3445. BenYashar, R. & Paroush, J. (2000), `A nonasymptotic Condorcet jury theorem', Social Choice and Welfare 17(2), 189199. Berg, S. (1993), `Condorcet's jury theorem: dependency among voters', Social Choice and Welfare 10, 8795. Black, D. (1958), The Theory of Committees and Elections, Cambridge University Press, Cambridge. Boland, P. J. (1989), `Majority systems and the Condorcet jury theorem', Journal of the Royal Statistical Society. Series D (The Statistician) 38(3), 181189. Boland, P. J.; Proschan, F. & Tong, Y. (1989), `Modelling dependence in simple and indirect majority systems', Journal of Applied Probability 26(1), 8188. Bovens, L. & Rabinowicz, W. (2006), `Democratic Answers to Complex Questions  an Epistemic Perspective', Synthese 150, 131153. Cohen, J. (1986), `An Epistemic Conception of Democracy', Ethics 97(1), 2638. Condorcet, Marquis, D. (1785), Essai sur l'application de l'analyse á la probabilité des décisions rendues á la pluralité des voix. Coughlan, P. J. (2000), `In defense of unanimous jury verdicts: mistrials, communication and strategic voting', American Political Science Review, 94, 37594. de Finetti, B. (1937). `La prévision: ses lois logiques, ses sources subjectives', Annales de l'institut Henri Poincaré, 7. 168. Dietrich, F. (2008), `The premises of Condorcet's jury theorem are not simultaneously justified', Episteme 58(1), 5673. Dietrich, F. & List, C. (2004), `A model of jury decisions where all jurors have the same evidence', Synthese 142, 175202. Estlund, D.; Waldron, J.; Grofman, B. & Feld, S. L. (1989), `Democratic Theory and the Public Interest: Condorcet and Rousseau Revisited', American Political Science Review 83(4), 13171340. Estlund, D. M. (2008), Democratic Authority: A Philosophical Framework, Princeton University Press, Princeton. Estlund, D. M. (1994), `Opinion leaders, independence, and Condorcet's Jury Theorem', Theory and Decision 36(2), 131162. Feddersen, T. & Pesendorfer, W. (1998), `Convicting the innocent: the inferiority of unanimous jury verdicts under strategic voting', American Political Science Review, 92, 2336. Gaus, G. (1997), `Does democracy reveal the voice of the people? Four takes on Rousseau', Australasian Journal of Philosophy 75(2), 141162. Goodin, R. E. & Spiekermann, K. (2011), 'Epistemic Aspects of Representative Government', European Political Science Review, forthcoming. Grofman, B. & Feld, S. L. (1988), `Rousseau's General Will: A Condorcetian Perspective', American Political Science Review 82(2), 567576. Grofman, B.; Owen, G. & Feld, S. L. (1983), `Thirteen Theorems in Search of the Truth', Theory and Decision 15, 261278. Kaniovski, S. (2010), `Aggregation of correlated votes and Condorcet's Jury Theorem', Theory and Decision 69(3), 453468. Ladha, K. K. (1995), `Information pooling through majorityrule voting: Condorcet's jury theorem with correlated votes', Journal of Economic Behavior & Organization 26(3), 353372. Ladha, K. K. (1993), `Condorcet's jury theorem in light of de Finetti's theorem', Social Choice and Welfare 10(1), 6985. Ladha, K. K. (1992), `The Condorcet Jury Theorem, Free Speech, and Correlated Votes', American Journal of Political Science 36(3), 617634. List, C. (2005), `The Probability of Inconsistencies in Complex Collective Decisions', Social Choice and Welfare 24(1), 332. List, C. & Goodin, R. E. (2001), `Epistemic Democracy: Generalizing the Condorcet Jury Theorem', Journal of Political Philosophy 9(3), 277306. Nitzan, S. & Paroush, J. (1984), `The significance of independent decisions in uncertain dichotomous choice situations', Theory and Decision 17(1), 4760. Owen, G.; Grofman, B. & Feld, S. L. (1989), `Proving a distributionfree generalization of the Condorcet Jury Theorem', Mathematical Social Sciences 17(1), 116. Pearl, J. (2000), Causality: models, reasoning and inference, Cambridge University Press, Cambridge. Reichenbach, H. (1956), The direction of time, University of California Press, Berkely. Rheingold, H. (2002), Smart mobs: the next social revolution, Perseus Publishing, Cambridge, MA. Romeijn, J. & Atkinson D. (2011), `A Condorcet jury theorem for unknown juror competence', Politics, Philosophy, and Economics, 10(3), 237262. Shapley, L. & Grofman, B. (1984), `Optimizing group judgmental accuracy in the presence of interdependencies', Public Choice 43(3), 329343. Sommerlad, F. & McLean, I. (1989), `The Political Theory of Condorcet', Social Studies Faculty Centre Working Paper, Oxford University, 1/89. Spiekermann, K. R Goodin, R. E. (2012), `Courts of Many Minds', British Journal of Political Science, 12, 555571. Sunstein, C. R. (2009), A constitution of many minds: why the founding document doesn't mean what it meant before, Princeton University Press, Princeton, N.J. Spirtes, P.; Glymour, C. & Scheines, R. (1993), Causation, prediction, and search, Springer, New York. Surowiecki, J. (2004), The wisdom of crowds: why the many are smarter than the few and how collective wisdom shapes business, economies, societies, and nations, Little Brown, London. Vermeule, A. (2009), 'Many Minds Arguments in Legal Theory', Journal of Legal Analysis 1(1), 145. 
URI:  https://mpra.ub.unimuenchen.de/id/eprint/40135 