ABSTRACT Central to the legal positivism of the nineteenth and the first half of the twentieth century was the dogma of the Ideal Legislator. Legal materials were to be interpreted as the work of an omniscient, coherent, consistent legislator. We argue that this dogma persists in the different guise of the competent speaker model, on which legal materials are the work of a competent speaker, who follows all the pertinent semantic and pragmatic rules. We will first lay out the Ideal Legislator dogma as applied in legal interpretation, arguing that this dogma does not limit interpretive discretion but rather amplifies it by hiding it under the veil of an inexistent, purely instrumental rationality. We will then turn to the competent speaker model, showing that, despite its apparent neutrality, it proves to be a reincarnation of the Ideal Legislator dogma, for it, too, amplifies interpretive discretion, only it hides it under the veil of an inexistent, purely linguistic rationality. Finally, we will inquire into the different types of rationality and their relations, arguing that there is always a choice and value judgment involved in ascribing rationality to legislators, and that these choices and judgments need to be carefully inspected and normatively justified.