How Should We Evaluate Chances?

old_uid14967
titleHow Should We Evaluate Chances?
start_date2015/01/22
schedule17h-19h
onlineno
summaryIt is standardly assumed that chances are not carriers of value, but are only instrumentally valuable in virtue of the outcomes with which they are associated. Learning that you have won a lottery, and that your chances of winning were, say, 0.000001, is on this view neither more nor less desirable than just learning that you have won the lottery. I call this view—implicitly assumed, for instance, in expected utility theory, risk analysis and orthodox economics---Chance Neutrality. The aim of this paper is to question the claim that Chance Neutrality is rationally required. I will do so by first showing that given Chance Neutrality, the Principal Principle---according to which a person should align her credence with her beliefs about objective chance---entails Linearity---the idea that the value of a lottery is equal to the sum of the values of the lottery’s prizes discounted by their probabilities. I then argue that the Principal Principle is a requirement of (both practical and theoretical) rationality but that Linearity is not. Hence, Chance Neutrality is not rationally required. I conclude with some remarks on implications for the Ellsberg paradox.
responsiblesBaccelli