Pluralism is the very idea of modern society. At a fundamental level this applies to the transformation of the concept of reason. Modernity rejects the traditional notion of a substantial reason that is directed at understanding a pre-given order and a teleologically determined world. Instead, reason is now thought of as procedural, as a capacity to create a meaningful world by using specific methods, arguments, and theories. For better or worse, what counts as reasonable is decided by each field of human endeavor according to its own standards. Reason becomes plural.
The "fact of pluralism" is the starting point for a political philosophy that observes deep disagreements in present society not only about the "good" but also about the "right." (1) The breeding ground for this development--in which reason has been differentiated into autonomous spheres of knowledge and practice--is the liberal idea of extending the principle of religious tolerance to other controversial questions about the meaning, value, and purpose of human life. (2) In this sense, liberalism is the historic catalyst for the pluralism that characterizes modern society. The medium for institutionalizing the freedom to endorse different instantiations of reason is the law. As it were, modernity becomes aware of itself in and through the law: "The greatest problem for the human race, to the solution of which Nature drives man, is the achievement of a universal civic society which administers law among men." (3) The type of law deemed best suited to achieve this goal was private law. Only a law whose leading idea is the enactment and protection of individual autonomy seemed able to accomplish "the development of all the capacities which can be achieved by mankind ... in the society with the greatest freedom."
In the course of unfolding the pluralism of modern society, the distinguished position occupied by liberal thought and liberal doctrine gave way to a spectrum of concurrent theories about the purpose and the structure of private law. All of these alternatives struggle with the fact that liberal doctrine organizes itself around the notion of the individual will without addressing the relation between individual rights and the conditions under which they are exercised. Paradoxically, other than liberalism itself, these theories also respond to the liberal opening up of reason. To be sure, the reflexivity that these theories add to the reasoning of private law is not necessarily plural in the sense that they construe rights as being placed in the context of different social domains and their respective values. Economic analysis of law, for instance, substitutes the liberal commitment to freedom with another (more narrow) exclusive orientation when it models the individual only in terms of a homo economicus, the decisions of which are subject to the imperative of efficiency. By contrast, deliberative and systems theoretical approaches start with the assumption of a legal pluralism and explicitly focus on the relation of different normative domains in a given case. However, none of the private law theories can claim to judge among the competing accounts. Pluralism in private law theory does not just indicate an acknowledged multiplicity of methods within legal science. Rather it embodies a controversy over different concepts of law that brings about different notions of the subject, the status, and the limits of legal reflexivity along with different standards of judicial control. Pluralistic theories are not exempt. They are parties to the controversy, too. There is no room for a monopoly on pluralism in private law theory.
Social pluralism has two main institutional backings. The obvious and often discussed one is democracy. Continuous possibility of change and the limited power of temporary rulers enables a diverse spectrum of political positions. A constitutional system of checks and balances and a human rights-inspired protection of minorities provide a strong legal basis for ethical self-determination. …