The notion of truth has been debated extensively by philosophers and scientists alike for centuries. Relativist and absolutist/objectivist philosophies have a complete different understanding of the value attached to this notion. In this presentation, I will discuss a number of issues related to the notion of truth in the biomedical sciences. I will first lay out different meanings and forms of truth and then discuss how this relates to the notion of causality. I will then describe how the biomedical science produces "truth" and lay down the different ways to achieve this (induction, causal inference, falsification, Baysian approach, etc..).  

I will then illustrate this by citing examples from the medical history and present-day biomedical research related to infectious disease, vascular biology and cancer research. I will then show that a strong relativist epistemology is incompatible with the way biomedical science obtains knowledge. Thus, in my view, a realistic notion of truth is central to achieve a sound understanding of physiology and pathology, and for the development of therapies grounded in a correct knowledge of disease.