(Translated from German original) How can the development of legal methodology be described? Is it necessary to include modern linguistic-philosophical questions and also formal methods from modern logic in order to meet the challenges of the present? How can competing systems be modelled in formal logic and balanced appropriately? What possibilities of computerised reasoning are already being implemented today? These questions are dealt with exemplarily on the basis of the remarkable decision of the BVerfG on the ECB bond purchase programme. A plea to recognise formal systems and models, as well as concepts of legal informatics, as an integral part of legal methodology in the future - "Methodenlehre 3.0".