This paper presents an analysis and critique of Roger Penrose’s epistemological, methodological, and ontological positions. The analysis is relevant not only because Penrose is an influential scientist, but also because of the particular traits of his thought. These traits are directly connected with his background and approach to science: ontological and epistemological realism, mathematical Platonism, emphasis on the continuities of science, epistemological inclusiveness and essential openness of science, the role of common sense, emphasis on the connection between science, ethics, and (...) philosophy. The paper articulates Penrose’s position and criticizes some of its possible shortcomings. It contributes to the perception of science as an open activity, as illustrated in Penrose’s particular approach, and provides an interesting case-study that can contribute to understanding how epistemological and ontological positions are connected with particular scientific practices. (shrink)