This paper analyses Bohr’s complementarity framework and applies it to biosemiotic studies by illustrating its application to three existing models of living systems: mechanistic biology, Barbieri’s version of biosemiotics in terms of his code biology and Markoš’s phenomenological version of hermeneutic biosemiotics. The contribution summarizes both Bohr’s philosophy of science crowned by his idea of complementarity and his conception of the phenomenon of the living. Bohr’s approach to the biological questions evolved – among other things – from the consequences of (...) an epistemological lesson of quantum theory and in light of complementarity of observer as a priori living creature and ex post scientific explanation of the living. In a manifestation of the phenomenon of the living, each model of living system and its description makes accessible – from its own presuppositions, contexts and concepts – some features which are not accessible from the others. Nevertheless, for a general understanding of that phenomenon, incompatible sophisticated approaches are equally necessary. Bohr’s epistemology of complementarity turns out to be a heuristic and methodical framework for testing the extent to which biosemiotics can become one of the special sciences or its potential as a cross-disciplinary branch of study. (shrink)