Can intergenerational equity be operationalized?

A long Utilitarian tradition has the ideal of equal regard for all individuals, both those now living and those yet to be born. The literature formalizes this ideal as asking for a preference relation on the space of infinite utility streams that is complete, transitive, invariant to finite permutations, and respects the Pareto ordering; an ethical preference relation, for short. This paper argues that operationalizing this ideal is problematic. Most simply, every ethical preference relation has the property that almost all (in the sense of outer measure) pairs of utility streams are indifferent. Even if we abandon completeness and respect for the Pareto ordering, every irreflexive preference relation that is invariant to finite permutations has the property that almost all pairs of utility streams are incomparable (not strictly ranked). Moreover, no ethical preference relation can be measurable. As a consequence, the existence of an ethical preference relation is independent of the axioms used in almost all of formal economics and all of classical analysis. Finally, even if an ethical preference relation exists, it cannot be "explicitly described." These results have implications for game theory, for macroeconomics, and for economic development.Intergenerational equity, infinite utility streams, long run averages, overtaking criterion, Utilitarianism

Competitive markets with externalities

This paper presents a general model of a competitive market with consumption externalities, and establishes the existence of equilibrium in the model, under assumptions comparable to those in classical models. The model allows production and indivisible goods. Examples illustrate the generality and applicability of the results.Competitive equilibrium, externalities, distributional economies

Prices and Portfolio Choices in Financial Markets: Theory, Econometrics, Experiments

Many tests of asset-pricing models address only the pricing predictions, but these pricing predictions rest on portfolio choice predictions that seem obviously wrong. This paper suggests a new approach to asset pricing and portfolio choices based on unobserved heterogeneity. This approach yields the standard pricing conclusions of classical models but is consistent with very different portfolio choices. Novel econometric tests link the price and portfolio predictions and take into account the general equilibrium effects of sample-size bias. This paper works through the approach in detail for the case of the classical capital asset pricing model (CAPM), producing a model called CAPM+ε. When these econometric tests are applied to data generated by large-scale laboratory asset markets that reveal both prices and portfolio choices, CAPM+εis not rejected