http://creativecommons.org/licenses/by/ , info:eu-repo/semantics/OpenAccess
Franz Dietrich et al., « Decision Under Normative Uncertainty », HAL-SHS : économie et finance, ID : 10670/1.ckmnk6
While ordinary decision theory focuses on empirical uncertainty, real decision-makers also face normative uncertainty: uncertainty about value itself. From a purely formal perspective, normative uncertainty is comparable to (Harsanyian or Rawlsian) identity uncertainty in the 'original position', where one's future values are unknown. A comprehensive decision theory must address twofold uncertainty — normative and empirical. We present a simple model of twofold uncertainty, and show that the most popular decision principle — maximising expected value ( 'Expectationalism') — has different formulations, namely Ex-Ante Expectationalism, Ex-Post Expectationalism, and hybrid theories. These alternative theories recommend different decisions, reasoning modes, and attitudes to risk. But they converge under an interesting (necessary and sufficient) condition.