Abstract
There is a substantial literature on the Bayesian approach, and the application of Bayes' theorem, to legal matters. However, I have found no discussion that explores fully the issue of how a Bayesian juror might be led from an initial "presumption of innocence" to the judgment (required for conviction in criminal cases) that the suspect is "guilty beyond a reasonable doubt". I shall argue here that a Bayesian juror, if she acts in accord with what the law prescribes, will virtually never reach such a judgment. In section I, I discuss Bayesianism, Bayes' rule and the relation between them. Section II addresses the two legal notions key to my worries about Bayesian jurors: the presumption of innocence and the reasonable doubt criterion. Section III explores what a Bayesian is to make of these notions, and how the legal system requires her to reason in their light. If I am right, there emerges a conflict between current legal prescriptions and the Bayesian approach. Section IV explores the import of this conflict and how it might be resolved.
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References
Bayes, T.: 1763, 'Essay towards Solving a Problem in the Doctrine of Chances', Phil.Trans.Roy.Soc. 53, 370–418 (Reprinted in Biometrika: 1958, 45, 293–315).
Blackstone, W.: 1807, The Law of England, Book the Fourth, Portland: T. Wait and Co.
Cohen, L.J.: 1977, The Probable and the Provable, Oxford: Clarendon Press.
de Finetti, B.: 1930, 'Fondamenti Logici del Ragionamento Probabilistico', Boll.Un.mat.Ital. 9 (Ser.A), 258–261.
de Finetti, B.: 1937, 'La Prévision: Ses Lois Logiques, Ses Sources Subjectives', Ann.Inst.Henri Poincaré 7, 1–68.
Edwards, W., Lindman, H. and Savage, L.J.: 1963, 'Bayesian Statistical Inference for Psychological Research', Psychological Review 70(3), 193–242.
Evett, I.W.: 1983, 'What is the Probability that This Blood Came from That Person? A Meaningful Question?', Journal of the Forensic Science Society 23, 35–39.
Fienberg, S. and Kadane, J.B.: 1983, 'The Presentation of Bayesian Statistical Analyses in Legal Proceedings', The Statistician 32, 88–98.
Finkelstein, M.O. and Fairley, W.B.: 1970, 'A Bayesian Approach to Identification Evidence', Harvard Law Review 83(3), 489–517.
Finkelstein, M.O. and Fairley, W.B.: 1971, 'A Comment on “Trial by Mathematics”', Harvard Law Review 84(8), 1801–1809.
Glymour, C.: 1980, Theory and Evidence, Princeton: Princeton University Press.
Goodman, N.: 1983, Fact, Fiction, and Forecast (4th ed.), Harvard University Press.
Jeffrey, R.C.: 1983, The Logic of Decision (second edition), Chicago: University of Chicago Press.
Jeffrey, R.C.: 1992, Probability and the Art of Judgment, Cambridge: Cambridge University Press.
Lindley, D.V.: 1977, 'Probability and the Law', The Statistician 26(3), 203–220.
Lindley, D.V.: 1983, 'Theory and Practice of Bayesian Statistics', The Statistician 32, 1–11.
Ramsey, F.P.: 1931, 'Truth and Probability' (1926) and 'Further Considerations' (1928) in The Foundations of Mathematics and Other Essays, New York: Harcourt, Brace.
Tribe, L.H.: 1971a, 'Trial by Mathematics: Precision and Ritual in the Legal Process', Harvard Law Review 84(6), 1329–1393.
Tribe, L.H.: 1971b, 'A Further Critique of Mathematical Proof', Harvard Law Review 84(8), 1810–1820.
Wigmore, J.H.: 1981, Evidence in Trials at Common Law, Vol. 9, revised by J.H. Chadbourn, Boston: Little, Brown & Co.
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Rawling, P. Reasonable Doubt and the Presumption of Innocence: The Case of the Bayesian Juror. Topoi 18, 117–126 (1999). https://doi.org/10.1023/A:1006290104372
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DOI: https://doi.org/10.1023/A:1006290104372