This chapter highlights the characteristic aspects of the approach to governance suggested by the neo-institutionalist economists. Recent neo-institutional research has clearly perceived the internal ambiguity in the undertaking of O. Williamson, the movement's founding father. The evolutionary approach's contribution to Williamsonian theory does not consist of the idea of learning. O. Williamson, working with H. Simon's bounded rationality hypothesis, was already pondering the question of economic agents' choice of governance mechanisms on the basis of the idea of learning. But making a process of selection by learning independent of any process of natural selection entails rethinking the question of whether the learning process automatically leads to the most efficient possible form of governance. The division of problem-solving labor into decentralized decision units coordinated by markets determines which solutions can be generated and tested by the selection process. Thus, the public authorities are understood to possess the function of reflexive legitimacy they were already credited with by classical democratic political theories.