Leibniz,Locke, and the Early Modern Controversy over Legal Maxims

This article investigates the context of a side line in Leibniz's critique of Locke on maxims. In an enigmatic and little-explored remark, Leibniz objects that Locke has overlooked some legal maxims that fulfil the function of ‘constituting the law’. I propose to read this remark against the background of the divergence between conceptions of legal maxims in the common law tradition and conceptions of legal maxims in the Roman law tradition. In a few remarks, Locke seems to echo the common law emphasis on customs and conventions expressed by legal maxims. According to such a conception, reason would mainly fulfil the function of subsuming particular norms under more general conventional norms. By contrast, Leibniz uses the Roman law idea that some ‘rules of law’ express demands of natural reason and, thereby, express principles constitutive of natural law. This is why he proposes to reform vague and confused ‘brocards’ used by jurists in order to identify sound maxims that provide a natural-law foundation for legal institutions.