This paper points to some limitations of law and economics as both an explanative and a normative theory. In explaining law as the result of efficiency promoting decisions, law and economics theorists often dismiss the reasons actors in the legal system give for their behavior. Recognizing that sometimes actors may be unaware of why institutions evolve as they do, I argue that the case for dismissing reasons for action is weaker when those reasons make reference to rules of practices that constitute the meaning of actions within those practices, or when they have otherwise been given well-considered defenses. In criticizing law and economics as a normative theory, I acknowledge that economic considerations are often important in deciding how to act in the personal sphere and how government should allocate its scarce resources. I argue that while the use of institutions to promote our ideals forces us to take their costs into account, it is a mistake to infer from this that the question of determining social policy is a purely economic problem, and that we should acknowledge the non-utilitarian moral ideals our law and practices promote. This is the basis of both an internal criticism--law and economics theorists have not sufficiently evaluated and weighed the value of fairness and other ideals in their utility calculations--and an external criticism-- these ideals are important in ways that can not be measured in utiles.