According to Jeremy Simon, a central focus of philosophy of medicine is to demonstrate how many unique and complex metaphysical, epistemic, and ethical issues may be adequately resolved within the practice of medicine. In the essay, “Constructive Realism and Medicine”, Simon aims to develop such a constructive realist metaphysics for medicine, and does so by critically examining sections of Ronald Giere’s position on the subject.
One metaphysical question raised by medicine in particular is asked by Simon, that is: “what is the ontological nature of the diagnostic entities that medicine considers?…[M]ore concretely, when a physician tells a patient ‘You have cystic fibrosis,’…what do they mean?” (354)
Ontologically, a disease can be defined as “an abstract entity that specifies the structure of part of an otherwise unspecified human organism.” (Simon, 363) Note that we must classify entities akin to diseases under particular models. The importance of this classification is that we are able to use knowledge of human physiology as a predictor about the behaviour of diseases (like cystic fibrosis), and as Simon continues, “[t]o the extent that a given model, by embedding the relevant causal structures, allows us to predict and affect the clinical course of a group of patients, that model will represent a (constructively) real disease.” (363)
How then do we answer the above question? That is, when a physician tells a patient, “You have cystic fibrosis,” what do they mean? Simply speaking, the physician is identifying the patient’s condition by referencing a particular disease model, which corresponds in this case to cystic fibrosis, and contains gratuitous amounts of scientific detail acquired over years of medical research. If models of disease are found to be useful, or to accurately represent the fundamental nature of a disease, physicians and researchers can then utilize the model to further their investigations, and to advance the medical sciences.