摘要：Post-positivism models had brought about the revival of the practical reason, which results in new architectures for the relation between Laws and Moral and in an uprising status for jurisprudence. However, the "implosion of practical reason" originally caused by hegelian Philosophy of Subject warns us to the need for beware about that revival. Thus, this paper reviews one of the most prolific theories that intend to sustain juridical legitimacy: Habermas' communicative reason. Firstly its rather convenient to briefly recall the definitions of pure reason, practical reason and instrumental reason, so as to keep in mind the limits of those categories. In a second moment, this paper recollects the communicative reason genealogy, focusing the analysis on Husserl's fenomenological assumption of Lebenswelt. We conclude, thus, presenting a summary of the limitations of communicative reason itself, quoting Luhmann's systemical theory.
