ABSTRACT
This chapter explains the use of 'lex certa', 'ius certum', and 'certitudo' as common criteria for postulating the basically scientific nature of both types of law. Amongst the disciplines 'in which others have an influence and therefore are useful', Daniel Nettelbladt includes 'above all positive jurisprudence' and he investigates influences on this, using the philosophy of Christian Wolff and his 'mathematical approach to teaching'. The ideal of 'certitudo' or legal certainty dominates the whole process of producing and implementing legislation. To preserve 'certitudo', even a customary and declared interpretation may not be relinquished: 'Minime sunt mutanda, quae Interpretationem certam semper habuerunt'. Jurisprudence and jurisdiction were to be excluded from the task of interpretation. If a 'dubium' arose, then it had to be returned to the status of a putative 'ius certum' by a decision of the Justice Department on the basis of the advice of the permanent 'State Legal Committee'.
