Why care about the precise definitions of the words health, disease, and illness? Their meanings seem self-evident: Health is the absence of disease, illness the experience of disease. However the multiple dimensions of these concepts, their moral underpinnings, and the purposes for which they are used are enormously complex, especially in a technological society strongly oriented toward the production of health.

Health and disease are more than just medical terms; they have social, political, moral, and economic dimensions. For example, a pharmaceutical company may advertise its new compound as the cure for a heretofore-unnamed disease such as erectile dysfunction or attention deficit disorder (ADD). Medical or disability coverage is granted or denied based on sociopolitical interpretations of what constitutes a disease or disability. A couple decides to use in vitro fertilization and preimplantation genetic screening to avoid creating a baby with a genetic disease...