Positive Political Theory II: Strategy and Structure

Preface

Preface As with its precursor, Positive Political Theory I: Collective Preference, this book is concerned with understanding the connection between individuals' preferences within any society and the collective choices of that society. Motivated by the canonical rational choice theoretic model of decision-making, Positive Political Theory I [PPTI] explores "the possibility that individual preferences are directly aggregated into a collective, or social, preference relation which ... is then maximized to yield a set of best alternatives (where "best" is here defined as being most preferred with respect to the collective preference relation)" [PPTI, p.xi]. To the extent that this is possible, therefore , a theory of political behavior can be built around an appropriate "as if" assumption, whereby the society as a whole is treated anthropomorphically as a single, representative, agent endowed with the social preference relation. Perhaps unfortunately, it turns out that direct preference aggregation yields a well-defined theory of political decisions in this sense only when the environment is relatively simple, having few alternatives or limited heterogeneity in the distribution of individual preferences, or when the political system endows some individuals with veto power over all collective choices. In complex environments or in polities where the approval of some particular individual or individuals is not required for all social decisions, however, the existence of "best alternatives" is not assured and the value of the direct aggregation theory as a positive theory of collective choice is attenuated. But the direct aggregation of individual preferences is not equivalent to the indirect aggregation of preferences through the aggregation of individual actions; in particular, actions to determine the alternatives for collective choice (agenda selection) and actions to determine the choice of an alternative from those available (voting). The difficulty with using a direct preference aggregation approach to develop positive (that is, explanatory or predictive) accounts of political behavior in relatively complex environments lies with an insistence that acceptable collective decisions respect a minimal democracy constraint, loosely, xiv PREFACE that no single individual gets his or her way whenever he or she is unanimously opposed by the rest of society. The argument of Positive Political Theory I is that, while this sort of constraint does not bind for simple decisions or relatively homogenous populations, it essentially precludes any acceptable compromise when decisions are complex or preferences heterogenous . Moreover, the indirect preference aggregation approach is not immune to this difficulty [PPTI, ch.7]. Developing an indirect preference aggregation theory requires developing a theory of how individual actions are linked, both to individual preferences and to the actions of others. The notion of a "wasted vote" in elections with, say, three candidates for a given office provides a clear example: an individual may strictly prefer candidate A to candidate B, and strictly prefer candidate B to candidate C; but if the individual believes or conjectures that sufficient numbers of other voters are voting for Band C to make A's chances of election negligible, then the individual is better off voting for B to minimize the chance that his or her least favorite candidate, C, wins. At ~he least, therefore, a coherent explanatory theory of how individuals act in such situations entails some notion of mutual consistency or compatibility among individual actions; without such consistency, every imaginable pattern of behavior is admissible and there is no basis on which to build a systematic account of collective choice. The notions of mutual consistency of concern in the chapters to follow are the equilibrium concepts of game theory. Thus the analogue to exploring the existence and characterization of suitably defined maximal sets of alternatives in the direct theory of collective preference is exploring the existence and characterization of suitably defined equilibrium sets of actions and the collective choices they induce. And it turns out that while equilibrium sets of actions quite generally exist, they occasionally imply some violation of the minimal democracy constraint. That is, an equilibrium outcome can be an alternative that is strictly less preferred to a distinct (non-equilibrium) outcome by all but at most one member of the society. Therefore, the direct (collective preference) and indirect (gametheoretic ) "approaches to the study of collective decision-making differ not with respect to existence of solutions per se but rather with respect to the implicit trade-off each makes between existence and minimal democracy" [PPTI, p.xv]. Analysing the implications of making this trade-off occupies the chapters to follow. We are especially interested in indirect preference aggregation through agenda-selection and voting within more-or...