Expected utilityis always used as aheuristic

Konrad Talmont-KaminskiMarie Curie-Sklodowska U., Poland

Line of argument

Problem with bounded rationalityDual systems of reasoningWhat is a heuristic?Expected utility as a heuristic

H. Simon Reason in Human Affairs, 1983

Bounded rationality

Processes satisficing not maximisingMethods context-dependentReasoning consists of heuristics

All reasoning?

Heuristics all the way up?

What about logical reasoning?What about scientific reasoning?Does not look like heuristicsBut…

Simon’s explanation of discovery of Boyle’s Law

J. EvansK. FrankishS. SlomanK. StanovichD. Kahneman& others

Dual reasoning

System 1Heuristics

Intuitive, quick, innate, automatic

System 2Real reasoningLogical, slow, learned, conscious

Kahneman’s system 1

Simple heuristicsAnchoring & adjustment, representativeness, availabilityDescriptiveFocus on errors producedNecessitated by empirical data

But Gigerenzer’s critique

Kahneman’s system 2

Logical reasoningUtility theory, etc.Descriptivebut also normativeNecessitated by desire to maintain classical norms of rationality &Need to explain ‘system 2’ reasoning

Expected utility

Paradigmatic exampleIf EU functions as heuristic, (plausibly) all reasoning doesEU does not function as Kahneman heuristicNeed to go back to Simon’s concept

Simon

Not necessarilyNot necessarilyNot necessarilyNot necessarily

Kahneman

IntuitiveInnateQuick

Automatic

Simon’s heuristics

Very broad categoryKahneman examplesBehavioural adaptationsScientific reasoningIn danger of becoming vacuousOnly useful if it supports substantive generalisations

Bill WimsattReengineering Philosophy for Limited Beings, 2007

Common traits of heuristics1. Fallible2. Efficient3. Systematically biased4. Problem-transforming5. Purpose relative6. Descended from other

heuristics

EU as heuristic?

EU formalism does not look like a heuristicBut how is EU applied in real situations?Using simplifying assumptionsNeed to consider formalism+assumption

Traits of EU+assumptions

1. Fallible2. Efficient3. Systematically biased4. Problem-transforming5. Purpose relative6. Descended from other

heuristics

?

?

Heuristics all the way up

EU functions as a heuristicMaximising formalism situated in satisficing methodologySame phenomenon in other cases?Kahneman’s ‘system 2’ not descriptiveProbably not primitively normative, either

H. MercierD. SperberWhy do Humans Reason,BBS forthcoming

Conclusions

It is heuristics all the way upKahneman’s conception of heuristics very limitedSimon’s conception much broader and more usefulNeed to go back to Simon

Thank you

Konrad Talmont-KaminskiIn a Mirror, Darkly: How the Supernatural Reflects Rationality (forthcoming)

konrad@talmont.comdeisidaimon.wordpress.com