EN
The vitality of the Roman law is a consequence of its utility for the development of the legal science since the Middle Ages. The 19 th century brought about two significant distinctions. First of all, the application of the Roman legal texts building a new private law system (the German Pandectist school) became the opposition to the science of the applied Roman law (ius commune). Second of all, the opposition between the ahistorical, although practical, application of the Roman law and the historical charm embedded in the ancient legal texts was clearly noticed. As a consequence of replacing the received Roman law with the civil law codes, the question whether, and how, to study Roman law usefully and how to teach it remains topical. Psychology suggests that, as a result of cognitive biases, the 19 th century understanding of the utility of the Roman law exists even today. The author believes these errors are worth overcoming. The combination of studies of the ancient Roman law and the European legal science based thereon shows why one should recognise the rationality of existence of a certain uncertainty in the private law. It teaches us what is of fundamental importance for coping when faced with such an uncertainty.