[Scientific evidence and discourse bioethics].

This paper studies the relationship between the positive sciences, in particular the biomedical sciences, and bioethical discourse. Mainly addresses the question of whether bioethics requires adequate biomedical data for their development as science and that importance have such data in bioethical discourse. It also discusses the criteria that should govern relations between bioethics and biomedical fields. Before this is done a brief study of scientific rationality and the degree of truth that can achieve the empirical sciences coming to the conclusion that to determine it is necessary starting from a theory of knowledge. From what we have called epistemological realism we have valued the type of rationality that has biomedical sciences. Then from this rationality we have proposed the relationship must exist between the scientific evidence and development of bioethics. We conclude that bioethics needs the biomedical sciences to develop properly as a science but at the same time this does not mean that bioethics is reduced to biomedical science or derived from it. In development of bioethics is necessary the data biomedical but not sufficient, it is condition for the solution of problem or conflict studied but requires that this data is integrated into an eminently ethical reasoning.