Characterising competitive equilibrium in terms of opportunity

This paper analyses alternative profiles of opportunity sets for individuals in an exchange economy, without assuming that individuals’ choices reveal coherent preferences. It introduces the concept of a ‘market-clearing single-price regime’, representing a profile of opportunity sets consistent with competitive equilibrium. It also proposes an opportunity-based normative criterion, the Strong Opportunity Criterion, which is analogous with the core in preference-based analysis. It shows that every market-clearing single-price regime satisfies the Strong Opportunity Criterion and that, in the limit as an economy is replicated, only such regimes have this property

Characterising Competitive Equilibrium in Terms of Opportunity

This paper is the first draft of a technical appendix to a chapter of a book I am writing, with the provisional title The Community of Advantage. The central argument of the book will be that many elements of the (classically) liberal tradition of normative economics do not depend on assumptions about individual rationality, and so it is possible for a behavioural economist to work in that tradition. I will propose an approach to normative economics that differs both from neoclassical welfare economics and from the various variants of soft paternalism that are currently being proposed by behavioural economists. My approach has two distinctive features. First, it is written from a contractarian perspective. That is, it is addressed to citizens as potential parties to mutually beneficial agreements, and not to an imagined benevolent despot or social planner. (A first draft of this part of the argument has been published as Sugden [2013].) Second, its normative criterion is opportunity, not welfare, happiness or well-being. Sections 1 to 4 of this paper follow the analysis in McQuillin and Sugden (2012), specialised to the one-period case and with minor changes in notation. The set-up, and the definition of the ‘opportunity criterion’ are slightly different from those used in Sugden (2004). The differences are explained in McQuillin and Sugden (2012). The argument in Section 5 is new