The Impartial Observer Theorem of Social Ethics

Following a long-standing philosophical tradition, impartiality is a distinctive and determining feature of moral judgments, especially in matters of distributive justice. This broad ethical tradition was revived in welfare economics by Vickrey, and above all, Harsanyi, under the form of the so-called Impartial Observer Theorem. The paper offers an analytical reconstruction of this argument, using a simple mathematical formalism, as well as a conceptual critique of each its premisses.Utilitarianism, Impartiality, Sympathy, Von Neumann- Morgenstern Utility Theory, Subjective Probability.

Elementary non-Archimedean utility theory

Herzberg F. Elementary non-Archimedean utility theory. MATHEMATICAL SOCIAL SCIENCES. 2009;58(1):8-14.A non-Archimedean utility representation theorem for independent and transitive preference orderings that are partially continuous on some convex subset and satisfy an axiom of incommensurable preference for elements outside that subset is proven. For complete preference orderings, the theorem is deduced directly from the classical von Neumann-Morgenstern theorem; in the absence of completeness, Aumann's [Aumann, R.J., 1962. Utility theory without the completeness axiom. Econometrica 30 (3), 445-462] generalization is utilized. (C) 2009 Elsevier B.V. All rights reserved

Utility-Based Utility

A major virtue of von Neumann-Morgenstern utilities, for example, in the theory of general financial equilibrium (GFE), is that they ensure time consistency: consumption-portfolio plans (for the future) are in fact executed (in the future) — assuming that there is perfect foresight about relevant endogenous variables. This paper proposes an alternative to expected utility, one which also delivers consistency between plan and execution — and more. In particular, the formulation affords an extremely natural setting for introducing extrinsic uncertainty. The key idea is to divorce the concept of filtration (of the state space) from any considerations involving probability, and then concentrate attention on nested utilities of consumption looking forward from any date-event: utility today depends only on consumption today and prospective utility of consumption tomorrow, utility tomorrow depends only on consumption tomorrow and prospective utility of consumption the day after tomorrow, and so on.Utility theory, Expected utility, Time consistency, Extrinsic uncertainty, Cass-Shell Immunity Theorem

The aggregate weak axiom in a financial economy through dominant substitution effects

Consider a two period financial economy with incomplete markets and with agents having von Neumann-Morgenstern utility functions. It is well known that when the economys endowments are collinear, the excess demand function will obey the weak axiom when certain mild restrictions are imposed on agents coefficient of relative risk aversion. This result is obtained through the application of a theorem on the law of demand (for individual demand) formulated independently by Milleron (1974) and Mitjuschin and Polterovich (1978). In this paper, we develop their arguments further and apply them to economies without collinear endowments. We identify conditions which guarantee that the economys excess demand function obeys the weak axiom near an equilibrium price.

Incertidumbre: loterías y riesgo.

In this paper we develop the theory of uncertainty in a context where the risks assumed by the individual are measurable and manageable. We primarily use the definition of lottery to formulate the axioms of the individual's preferences, and its representation through the utility function von Neumann - Morgenstern. We study the expected utility theorem and its properties, the paradoxes of choice under uncertainty and finally the measures of risk aversion with monetary lotteries

A Unified Approach to Information, Knowledge, and Stability

Within the context of strategic interaction, we provide a unified framework for analyzing information, knowledge, and the "stable" pattern of behavior. We first study the related interactive epistemology and, in particular, show an equivalence theorem between a strictly dominated strategy and a never-best reply in terms of epistemic states. We then explore epistemic foundations behind the fascinating idea of stability due to J. von Neumann and O. Morgenstern. The major features of our approach are: (i)unlike the ad hoc semantic model of knowledge, the state space is constructed by Harsanyi’s types that are explicitly formulated by Epstein and Wang (Econometrica 64, 1996, 1343-1373); (ii)players may have general preferences, including subjective expected utility and non-expected utility; and (iii) players may be boundedly rational and have non-partitional information structuresepistemic games; Harsanyi's types; interactive epistemology; stability; non-expected utility; bounded rationality

Utility-Based Utility

A major virtue of von Neumann-Morgenstern utilities, for example, in the theory of general financial equilibrium (GFE), is that they ensure intertemporal consistency: consumption-portfolio plans (for the future) are in fact executed (in the future) — assuming that there is perfect foresight about relevant endogenous variables. This note proposes an alternative to expected utility, one which also delivers consistency between plan and execution — and more. In particular, it turns out that one special case is in fact simply discounted (subjective) expected utility. Moreover, this alternative formulation affords an extremely natural setting for introducing extrinsic uncertainty. The key idea behind my approach is to divorce the concept of filtration (of the state space) from any considerations involving probability (on the state space), and then concentrate attention on nested utilities of consumption looking forward from any date-event: utility today depends only on consumption today and prospective utility of consumption tomorrow, utility tomorrow depends only on consumption tomorrow and prospective utility of consumption the day after tomorrow, and so on.Utility theory, Expected utility, Intertemporal consistency, Extrinsic uncertainty, Cass-Shell Immunity Theorem

von Neumann-Morgenstern and Savage Theorems for Causal Decision Making

Causal thinking and decision making under uncertainty are fundamental aspects of intelligent reasoning. Decision making under uncertainty has been well studied when information is considered at the associative (probabilistic) level. The classical Theorems of von Neumann-Morgenstern and Savage provide a formal criterion for rational choice using purely associative information. Causal inference often yields uncertainty about the exact causal structure, so we consider what kinds of decisions are possible in those conditions. In this work, we consider decision problems in which available actions and consequences are causally connected. After recalling a previous causal decision making result, which relies on a known causal model, we consider the case in which the causal mechanism that controls some environment is unknown to a rational decision maker. In this setting we state and prove a causal version of Savage's Theorem, which we then use to develop a notion of causal games with its respective causal Nash equilibrium. These results highlight the importance of causal models in decision making and the variety of potential applications.Comment: Submitted to Journal of Causal Inferenc