In this article, it is proposed to take the differences in the practice of EU law seriously. The aim is not to construct a ‘correct’ content of European legal rules, concepts and methods, which would be different from their content in the legal practices studied, neither to discover the economic and political interests ‘hidden’ behind the use of EU legal arguments. The local practices of EU law are studied in their own discursive and cultural context. Their interpretation gives us important information on the legal cultures in which these practices evolve, but also on EU law and EU integration. The proposed approach is exemplified through the narration of the story of purposive interpretation in the common law. This technique, typical of Continental systems and of the case law of the ECJ, was long rejected in the common law as a prohibited trespassing of the limits of judicial competence. Its reception under the influence of European law has been the vector of a significant transformation of the common law into a rational legal order based on substantive values. While this proves that convergence between European legal systems is possible, it also shows that this convergence does not necessary imply the advancement of socio-political integration in Europe. Once received in the common law, the technique of purposive interpretation is reinvented to serve common lawyers’ goals, which do not always coincide with those of European institutions and of the ECJ.