EN
Among the fields of interests of the European jurisprudence the concept of legal certainty plays a significant role. Whereas Americans, at least those of a more progressive orientation, seem to proclaim “we are all realists now”, and declare that they are no longer interested in this topic. The indeterminacy thesis made in America is a matter of their concern. Firstly, being inspired by these completely different approaches, I try to bring forward the issue of legal certainty and present the indeterminacy thesis. The presented analysis focuses only on one element of the legal certainty concept – the predictability. As the concept of predictability seems to be enigmatic, I try to explore particularly what exactly is demandable by the requirement of predictability and when it is satisfied – the literature does not provide an answer here. Secondly, when referring to the decision theory, I put forward a maximalistic understanding of this requirement and claim that only this one is capable of fulfilling the aims which are commonly associated with legal certainty.The problem is that the presented understanding of the requirement of legal certainty is not only maximalistic but unrealistic too. The indeterminacy thesis explains why it is so.