1. Expected utility is always used as a heuristic Konrad Talmont-Kaminski Marie Curie-Sklodowska U., Poland

2. Line of argument Problem with bounded rationality Dual systems of reasoning What is a heuristic? Expected utility as a heuristic

3. H. Simon Reason in Human Affairs, 1983 Bounded rationality Processes satisficing not maximising Methods context-dependent Reasoning consists of heuristics All reasoning?

4. Heuristics all the way up? What about logical reasoning? What about scientific reasoning? Does not look like heuristics But… Simon’s explanation of discovery of Boyle’s Law

5. J. Evans K. Frankish S. Sloman K. Stanovich D. Kahneman & others Dual reasoning System 1 Heuristics Intuitive, quick, innate, automatic System 2 Real reasoning Logical, slow, learned, conscious

6. Kahneman’s system 1 Simple heuristics Anchoring & adjustment, representativeness, availability Descriptive Focus on errors produced Necessitated by empirical data But Gigerenzer’s critique

7. Kahneman’s system 2 Logical reasoning Utility theory, etc. Descriptive but also normative Necessitated by desire to maintain classical norms of rationality & Need to explain ‘system 2’ reasoning

8. Expected utility Paradigmatic example If EU functions as heuristic, (plausibly) all reasoning does EU does not function as Kahneman heuristic Need to go back to Simon’s concept

9. Simon Not necessarily Kahneman Intuitive Innate Quick Automatic

10. Simon’s heuristics Very broad category Kahneman examples Behavioural adaptations Scientific reasoning In danger of becoming vacuous Only useful if it supports substantive generalisations

11. Bill Wimsatt Reengineering Philosophy for Limited Beings, 2007 Common traits of heuristics 1.Fallible 2.Efficient 3.Systematically biased 4.Problem-transforming 5.Purpose relative 6.Descended from other heuristics

12. EU as heuristic? EU formalism does not look like a heuristic But how is EU applied in real situations? Using simplifying assumptions Need to consider formalism+assumption

13. Traits of EU+assumptions 1.Fallible 2.Efficient 3.Systematically biased 4.Problem-transforming 5.Purpose relative 6.Descended from other heuristics ? ?

14. Heuristics all the way up EU functions as a heuristic Maximising formalism situated in satisficing methodology Same phenomenon in other cases? Kahneman’s ‘system 2’ not descriptive Probably not primitively normative, either H. Mercier D. Sperber Why do Humans Reason, BBS forthcoming

15. Conclusions It is heuristics all the way up Kahneman’s conception of heuristics very limited Simon’s conception much broader and more useful Need to go back to Simon

16. Thank you Konrad Talmont-Kaminski In a Mirror, Darkly: How the Supernatural Reflects Rationality (forthcoming) konrad@talmont.com deisidaimon.wordpress.com