The real motive of this Article is quite general: to explore the most basic considerations arguing for and against major sources of rules. But it takes an inductive approach. The first part describes some key aspects of the recent debate about the choice between mandatory and enabling rules in corporate law. Its purpose is to illustrate the troubled dominance of one major model of the creation of norms—the contractual model—in academic thinking. Later parts explore factors slighted by users of this model, and in doing so introduce ideas that reach far beyond the borders of business law.