Suchergebnisse

Résumé Le Dominateur de Diodore Kronos donne un ensemble de prémisses contradictoires, l'une d'entre elles correspondant à un principe d'incertitude. Il conclue ainsi à une certaine forme de nécessité. L'objet de cet article est d'examiner si le cadre utilisé pour décrire l'incertitude dans la théorie économique est soumis à l'aporie de Diodore, si les hypothèses retenues en économie de l'incertain correspondent aux prémisses contradictoires. Cette question dépasse le contexte économique car elle touche à la théorie des probabilités. Pour cela, nous reprendrons l'écriture du Dominateur en logique des modalités et en donnons une démonstration directe. Nous exposons ensuite une modélisation qui permet de rapprocher les modalités du formalisme traditionnel de l'incertitude et réécrivons ainsi les prémisses de Diodore. Il est alors possible de retrouver l'aporie dans une version probabiliste et de conclure sur une éventuelle contradiction dans cette approche.

This book uses real-world examples to show how individual and collective risks can be blended and treated in a reliable decision-making framework that draws its inspiration from decision theory and market based mechanisms. It then goes into deeper detail by looking at the implications of having to face risks (a) where some kind of probabilistic description is available and (b) where none is available, using the example of insurable risks vs non-insurable risks. Again, by using real-world examples it shows how decision-makers can cope with such situations by a proper understanding and use of mo

Bon nombre de commentateurs admettent l'influence de Nietzsche dans la conception schumpétérienne de l'entrepreneur. Mais, de notre point de vue, cette influence est souvent traitée exclusivement dans le contexte historique et dans une version très réductrice de l'entrepreneur. Nous avançons que ce dernier gagnerait à se lire sous un angle philosophique, en particulier à travers une interprétation nietzschéenne axée sur la volonté de puissance, même si, évidemment, Schumpeter n'a pas voulu aller si loin. JEL classification : B13, M13

This paper studies the application of the two most popular non-expected utility (NEU) models -Choquet Expected Utility (CEU) and Maximin Expected Utility (CEU)- to dynamic choice situations in a purely subjective framework. We give an appropriate version of the reduction of compound acts axiom, that states the equivalence between a static and a dynamic choice situation. We show that if consequentialism -only those consequences that can be reached do matter- is additionally assumed, then a monotonic constant linear representation degenerate into expected utility. We envisage two different ways to resolve this problem for the cases where the representation is a CEU or a MEU one. One way consists to weaken the reduction of compound acts axiom, which does not hold on all events. Another way is to relax consequentialism. Then we axiomatically characterize an updating rule for both approaches allowing recursion in several cases.

This paper studies learning under multiple priors by characterizing the decision maker's attitude toward information. She is incredulous if she integrates new information with respect to only those measures that minimizes the likelihood of the new information and credulous if she uses the maximum likelihood procedure to update her priors. Both updating rules expose her to dynamic inconsistency. We explore different ways to resolve this problem. One way consists to assume that the decision maker's attitude toward information is not relevant to characterize conditional preferences. In this case, we show that a necessary and sufficient condition, introduced by [Epstein L. and Schneider M., 2003. Recursive multiple priors. Journal of Economic Theory 113, 1-31], is the rectangularity of the set of priors. Another way is to extend optimism or pessimism to a dynamic set-up. A pessimistic (max-min expected utility) decision maker will be credulous when learning bad news but incredulous when learning good news. Conversely, an optimistic (max-max expected utility) decision maker will be credulous when learning good news but incredulous when learning bad news. It allows max-min (or max-max) expected utility preferences to be dynamically consistent but it violates consequentialism because conditioning works with respect to counterfactual outcomes. The implications of our findings when the set of priors is the core of a non-additive measure are explored.