The epistemological paradigm of Systematic Neo-Pragmatism, supported by the author, is closely connected with the (semiotic-) pragmatical notion of “model”. The latter is expounded, and the models in medicine are characterised on the basis of flow charts and correlation-diagrams of the process of diagnosis. Furthermore, the neo-pragmatic concept of medicine is developed and it is shown how medicine is to be defined as a science of action. Finally, a holistic notion of reality in medicine is presented for which the interaction of subject and object as well as the unity of knowledge and action is important.