Introduction to a Theory of Legal Monsters

The paper distinguishes two kinds of ‘legal monster’ — i.e. either legal monsters as the object of legal regulations, or legal monsters as a source of criticism. The claim is, on the one hand, that drawing on the Roman law’s notion of ‘monstrum vel prodigium’ the formula can be considered legally dead nowadays; on the other hand, the formula can still represent a powerful metaphor of legal criticism insofar as it is supported by a strong philosophical framework and robust arguments of positive law. By providing such framework and making it operational with the case study of the AI Act, the aim is to illustrate eight kinds of monster that contradict requirements of positive law, or its functions, i.e., what positive law is supposed to do. The formula ‘legal monster’ is indeed a powerful tool of criticism that, handed down by a thousand-year-old tradition, deserves to be used even today: there is no shortage of such legal cases.