Brauchen wir einen Schleier der Unkenntnis

John Rawls’ and James Buchanan’s social contract theories maintain that rational actors, under a thick veil of ignorance/uncertainty, will always take unanimous and fair decisions. In sharp contrast to this received opinion the author shows, by means of a simple model, that - if the social contract is threatened by a prisoner’s dilemma incentive structure - players under uncertainty will not necessarily consent on a „fair“ rather than a discriminatory rule and that they may even fail to agree at all. On the other hand, absent a veil of ignorance/uncertainty a fair consensus will always be the iterated dominance equilibrium in the game of rule choice. The question is raised why, nevertheless, in reality we often have so much trouble to come to a consensus and why we intuitively feel that we need a veil of ignorance/uncertainty for making decisions on rules.