Models of Medical Thinking

In this paper, I focus on reasoning about individual cases in medicine. The relevance of the individual case has always been present both in medical and clinical research and has acquired further significance in recent times. Here, after recalling the importance of reasoning about individual cases, I introduce the distinction between general and singular causation and explain why medical reasoning needs the latter. I then consider three areas in which this necessity is most apparent: diagnosis, early phase clinical trials in oncology, and forensic medicine. I argue that the best approach to this form of causal reasoning is the counterfactual approach provided by structural equation models. I conclude by presenting some considerations on the relation between the building of structural models for singular causation and the contemporary “data deluge.” The aim of this paper is mainly philosophical: it is an attempt to interpret some actual medical approaches in a new perspective and at the same time connect some aspects of contemporary trends of research in medicine and bioinformatics with some classical philosophical questions. I do not give practical suggestions, but I am also persuaded that philosophical work on kinds of reasoning and on singular causation can be of interest for practicing physicians and experts in other fields.