Evidential decision theory
Encyclopedia
Evidential decision theory is a school of thought within decision theory
according to which the best action is the one which, conditional on your having chosen it, gives you the best expectations for the outcome. It contrasts with causal decision theory
, which requires a causal connection between your actions and the desirable outcome.
of an action 
"calculated from conditional probabilities":
where
is the desirability of outcome 
and 
is the conditional probability
of
given 
.
has characterized evidential decision theory as promoting "an irrational
policy of managing the news". 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."
Decision theory
Decision theory in economics, psychology, philosophy, mathematics, and statistics is concerned with identifying the values, uncertainties and other issues relevant in a given decision, its rationality, and the resulting optimal decision...
according to which the best action is the one which, conditional on your having chosen it, gives you the best expectations for the outcome. It contrasts with causal decision theory
Causal decision theory
Causal decision theory is a school of thought within decision theory which maintains that the expected utility of actions should be evaluated with respect to their potential causal consequences...
, which requires a causal connection between your actions and the desirable outcome.
Description
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":where
is the desirability of outcome and is the conditional probabilityConditional probability
In probability theory, the "conditional probability of A given B" is the probability of A if B is known to occur. It is commonly notated P, and sometimes P_B. P can be visualised as the probability of event A when the sample space is restricted to event B...
of
given .Criticism
David LewisDavid Kellogg Lewis
David Kellogg Lewis was an American philosopher. Lewis taught briefly at UCLA and then at Princeton from 1970 until his death. He is also closely associated with Australia, whose philosophical community he visited almost annually for more than thirty years...
has characterized evidential decision theory as promoting "an irrational
policy of managing the news". 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."
External links
- Causal Decision Theory at the Stanford Encyclopedia of PhilosophyStanford Encyclopedia of PhilosophyThe Stanford Encyclopedia of Philosophy is a freely-accessible online encyclopedia of philosophy maintained by Stanford University. Each entry is written and maintained by an expert in the field, including professors from over 65 academic institutions worldwide...