Evidential decision theory

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Evidential decision theory is a school of thought within decision theory according to which the best action is the one which, conditional on one's having chosen it, gives one of the best expectations for the outcome. It contrasts with causal decision theory, which requires a causal connection between one's actions and the desirable outcome.


In a 1981 article, Allan Gibbard and William Harper characterized evidential decision theory as maximization of the expected utility of an action "calculated from conditional probabilities":[1]

where is the desirability of outcome and is the conditional probability of given .


David Lewis has characterized evidential decision theory as promoting "an irrational policy of managing the news".[2] James M. Joyce asserted, "Rational agents choose acts on the basis of their causal efficacy, not their auspiciousness; they act to bring about good results even when doing so might betoken bad news."[3]

See also[edit]


  • Ahmed, Arif (2014). Evidence, Decision and Causality. Cambridge University Press. ISBN 9781139107990.


  1. ^ Gibbard, A.; Harper, W.L. (1981), "Counterfactuals and two kinds of expected utility", Ifs: Conditionals, Beliefs, Decision, Chance, and Time: 153–190
  2. ^ Lewis, D. (1981), "Causal decision theory" (PDF), Australasian Journal of Philosophy, 59 (1): 5–30, doi:10.1080/00048408112340011, retrieved 2009-05-29 CS1 maint: discouraged parameter (link)
  3. ^ Joyce, J.M. (1999), The foundations of causal decision theory, p. 146

External links[edit]