The present paper proposes to interpret the differences in legal systems between common-law and civil-law nations as arising from the importance given to adjudication in comparison with statute laws. It focuses on the relative costs of legal change by adjudication (case law development) when compared with legislation (statutory law development). The main argument is that the public concern with equality is a major determinant of the relative cost of adjudication in a legal system. We develop a model of the legal process that illustrates Tocqueville's fundamental intuition with regard to the uniformity of legal rules, and as a consequences, the relative importance of adjudication and legislation.