The One and the Many: Translating Insights from Constitutional Pluralism to European Contract Law Theory

While freedom of contract has generally been recognized as a leading principle of European contract law, national contract laws as well as EU measures show remarkable differences with respect to the limits they impose on contractual freedom in light of the public interest or common good. Whereas some private legal scholars aspire to relate all rules of private law to a single value (monist theories), others consider it impossible to find such a common denominator (radical pluralist theories). In this paper, it is submitted that a moderate pluralist theory offers the most convincing narrative to explain current developments in this field, since it defines a meta-level on which diverging ideas of contract law can be reconciled by the definition of coordinating principles. These meta-principles indicate which conception of the common good prevails in a specific case and on which level (European or national) final decision-making authority is allocated in that case. Through an analysis of examples from case law (the story of the CJEU's Viking and Laval judgments and the Court's recent decision in the Aziz case), it is argued that a moderately pluralist theory also provides the most convincing normative model for the further development of European contract law.