The current digitisation of law makes it possible to revisit the historical links between law and modern logic. Building on J. van Heijenoort's distinction between logic "as calculus" and logic "as language", the article draws analogies between different interpretations of logic and different types of legal systems and institutions: "Common law", "civil" systems, "court of cassation", the latter notion characterising Hilbertian formalism. This formalism attempted to reduce logic "as language" to logic "as calculus" but the discovery of the internal limits of formalisms put an end to it: hence the parallel between the failure of the Hilbertian programme and the difficulties encountered in the current digitisation of law. Law is not reducible to a formal calculation on written marks: it remains a discipline in which speech and dialogue are indispensable to achieving its goals.