The Concept of Disease

Abstract

Diagnosis is the process of giving a name to a particular condition, usually thought to be a disease. Before discussing the process of diagnosis, then, it will be useful to examine more closely what we mean by the term “disease.” “Disease” can refer to the class of all diseases. It can also refer to various subsets of this class, such as pneumonia, and further subsets, such as bacterial pneumonia and viral pneumonia. Finally, “disease” can refer to a single instance of a particular subset of disease such as viral pneumonia. Furthermore, several terms such as “disease,” “illness,” and “sickness” are used in common parlance in an imprecise manner. In addition, virtually all disease classifications, which are called nosologies, include entities such as injuries, disabilities and deformities, which most people would not consider to be diseases. How we classify these conditions will be the topic of chapter 5. For now, my task is to examine the concept of disease itself.