The purpose of this work is to reconsider and critically discuss the conceptual foundations of modern biology and bio-sciences in general, and provide an epistemological guideline to help framing the teaching of these disciplines and enhancing the quality of their presentation in High School, Master and Ph.D. courses. After discussing the methodological problems that arise in trying to construct a sensible and useful scientific approach applicable to the study of living systems, we illustrate what are the general requirements that a (...) workable scheme of investigation should meet to comply with the principles of the Galilean method. The amazing success of basic physics, the Galilean science of election, can be traced back to the development of a radically “reductionistic” approach in the interpretation of experiments and a systematic procedure tailored on the paradigm of “falsifiability” aimed at consistently incorporating new information into extended models/theories. The development of bio-sciences seems to fit with neither reductionism, nor falsifiability. Should we conclude that biology is not a science in the Galilean sense? We want to show that this is not so. Rather in the study of living systems, the novel interpretative paradigm of “complexity” has been developed that, without ever conflicting with the basic principles of physics, allows organizing ideas, conceiving new models and understanding the puzzling lack of reproducibility that seems to affect experiments in biology and in other modern areas of investigation. In the delicate task of conveying scientific concepts and principles to students as well as in popularising bio-sciences to a wider audience, it is of the utmost importance for the success of the process of learning to highlight the internal logical consistency of biology and its compliance with the fundamental laws of physics. (shrink)