4 What is a medical theory?

An account of the nature of medical theories illuminates many aspects of the development and application of medical knowledge. It contributes to the understanding of medical explanation, both at the general level of the causes of diseases and at the individual level of the diagnoses of particular cases of a disease. The syntactic, model-theoretic, paradigm, and third-world accounts fail to capture the complexity of medical theories and explanations. Explanations of a disease do not always need to go down to the deep biochemical level displayed. Depending on the problem and audience at hand, a medical explanation may operate at a superficial level—for example, when physicians tell their patients how they got sick. The most important task in medical research after determining the cause of a disease is developing a treatment for it. While drug discovery used to be largely a matter of serendipity or exhaustive search, current pharmaceutical research is based on a deep understanding of the molecular bases of a disease. Once investigators identify the way defective pathways lead to various diseases, they can search selectively for drugs that correct the defects. Psychology and the other fields of cognitive science have contributed to the powerful theories of mental representation and processing—for example, the theories of concepts, rules, images, and neural networks.