Why So Much Consensus?
An even more holistic approach to the problem is adopted by looking at how collective decision-making impacts the choices and characteristics of individual agents, e.g. their shareholdings, their beliefs about economic prospects, or even their preferences. The thesis is that individual characteristics shape collective choices and are at the same time shaped by them, forming a duality between persons and groups. The analysis is deployed on the network of affiliation of investors to firms. Indeed, suppose the Pareto principle holds at both the collective and individual levels, then a full agreement between all agents occurs within a cluster of investors and firms, despite potentially severe market failures—the ‘single thought’ theorem. Efficiency results from the endogeneity of individual characteristics, yet the theorem is strikingly strong and clear-cut. An analysis of what it takes for the Pareto principle to hold is proposed in each of the three contexts of market failure.