The semantic and logical quagmires that await any­one audacious enough to safari through the changing concepts of disease, illness, and health are por­tended by a cursory analysis of the definition formu­lated by the World Health Organization.

“Health,” we are informed, “is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” (Caplan, Engel­hardt, and McCartney 1981).

This essay concentrates on ideas of physical health and disease, which is not to minimize the importance of psychiatric disease, but rather to ad­mit that concepts of mental health and illness, al­though sharing most of the definitional difficulties of physical health and disease, are even more diffi­cult to handle. In large part this is because with mental illness we lack the kinds of objective tools to measure brain function that have helped, though not resolved, questions of what constitutes health and disease in the physical realm. This is not, how­ever, to deny the interconnectedness of the psychic and the physical, which is assumed in all of what follows.

Perhaps no one sentence captures the history of changing notions about disease better than a para­phrase of Humpty Dumpty’s haughty admonition: “When I use the word disease, it means just what I choose it to mean - neither more nor less.” Disease has always been what society chooses it to mean - neither more nor less. A number of important consid­erations lead to this generalization. Among these are the following: (1) The definition of disease has varied with time and place in history; (2) the names assigned to diseases are ultimately abstractions, al­though it is useful at times to act as though they are real; (3) what we mean by diagnostic terms, as with words in general, can be discerned more accurately by what we do with them than what we say about them.

There have been countless attempts to define ill­ness, disease, and health (Faber 1923; Riese 1953; Lush 1961; Meador 1965; Hudson 1966; Niebyl 1971; Boorse 1975; Burns 1975; Engel 1977; Temkin 1977; Taylor 1979; King 1982; Sundstrom 1987). Most share certain features, but it remains a practical certainty that no mortal could come up with short definitions of these words that would satisfy all who have an interest in them.

Although they will not be treated in what follows, even traditional definitions of death are no longer sufficient. This is due, in part, to the same develop­ments in knowledge and technology that have forced us continually to redefine our notions of health and disease. Death, according to Webster’s Third New International Dictionary, is the “cessation of all vital functions without capability of resuscitation.” But we now have a state of existence that may last many minutes in which there are no apparent vital func­tions, but during which the capability of resuscita­tion is unknown. What do we call such a state of existence? This confounding of traditional defini­tions by today’s knowledge and technology leads to such strange article titles as “Prevention of Recur­rent Sudden Death” (Rapaport 1982).

The judicious historian, after even a dampening immersion into the literature of changing concepts of disease, will conclude that the subject is unmanage­able in a brief essay. Accordingly, what follows ex­cludes non-Western concepts Ofdisease and focuses on the tension between those who believed diseases were real entities with an existence of their own (ontolo- gists) and the opposing camp, which held that disease should be viewed properly as illness, as a unique process in one person over time (physiologists).

The ontology-physiology tension has persisted be­cause physicians perceive that, at a minimum, they must have a reasonably precise definition of what they mean by disease in order to distinguish them­selves as professionals. Try to imagine convincing a patient to submit to exploratory abdominal surgery without using a diagnostic term; or to study pathol­ogy without the use of disease names; or to mount fund-raising campaigns without words such as can­cer or muscular dystrophy.

The question of disease vis-a-vis illness is not sim­ply an intriguing philosophical persistency, al­though it has been a source of much intellectual enjoyment as well as frustration. The viewpoint adopted has definite implications for what physi­cians do in practice. Lord H. Cohen perceived five dangers in an inordinate ontological orientation:

It promotes a “penny-in-the slot machine” approach to diagnosis by seeking for pathognomonic signs, especially the short cuts of the laboratory;... it suggests that diagno­sis is arrived at by comparing an unknown with a cata­logue of knowns; the method of recognizing an elephant by having seen one before;... it reduces thought to a mini­mum;... it is oflittle help and may be positively mislead­ing where the disease process varies significantly from the usual; and... it leads to all those dangers associated with a label which Cowper implied when he wrote of those - “who to the fascination of a name, surrender judgment, hoodwinked.” (Lush 1961)

In this view, the diagnostic label attached to a patient tends to dictate the treatment that follows. If the patient is jaundiced, has pain in the right upper abdomen that radiates through to the back beneath the scapula, and the X-ray demonstrates gallstones, the diagnostic label is cholelithiasis and the treat­ment is removal of the stones. “Surgery does the ideal thing,” wrote a health columnist around 1930 in a statement of pristine ontology, “it separates the patient from his disease. It puts the patient back to bed and the disease in a bottle” (Clendening 1931). But are such patients really separated from their diseases? They retain the genetic predisposition or eating habits or whatever produced the gallstones originally. Somehow it seems insufficient to speak of separating patients and diseases with such ready surgical facility.

A complete reliance on the opposite notion of ill­ness has hazards of a different sort. Physicians who think largely in terms of illness aptly consider the whole patient, but if they are ignorant of the natural history of the disease, they may miss the diagnosis and, for example, operate needlessly or too late.

A number of commentators have accepted as fact that disease is ultimately defined by the words and deeds of those persons constituting a given society. They agree as well that physicians usually have had an important voice in these social definitions. What is often neglected at this point is the role that the biology of diseases has played in shaping societal conceptions of the nature of disease (Risse 1979).

Granted that cultural, social, and individual con­siderations contribute to the expression of diseases in society, we may not overlook the importance of the biological aspects unique to diseases. A current ex­ample is the acquired immune deficiency syndrome (AIDS). The period of time between infection with the human immunodeficiency virus (HIV) and the body’s development of a testable antibody response can be as long as a year. One practical consequence of this inherent characteristic of the virus is that, during this period of time, blood that tests negative for the antibody may be transfused and infect recipi­ents. Furthermore, the period between infection with the virus and development of the clinical dis­ease may be 8 to 10 years or longer. This trait of the HIV greatly confounds the question of who should be tested for AIDS and what a positive test means. Thus, even as we correctly emphasize the role of cultural factors in the spread of AIDS (homosexual activity and intravenous drug use), we may not for­get the central importance of the biological charac­teristics of the virus itself.

This critical significance of the nature of the dis­ease appears in earlier historical examples as well. One of the most intriguing mysteries in the history of disease is that the Greeks, in the words of Karl Sudhoff, were “blind to the fact of contagion” (Ad­ams 1886; Garrison 1929).

Nonetheless, Contagionism was never completely eliminated from medical thinking after the accep­tance of the Jewish Old Testament as a holy book in the Christian religion. In large part this was be­cause of the attention accorded leprosy, which in­creased with the return of the Crusaders from the Middle East. The notion of disease as contagious was even more strongly reinforced by the sweeps of bu­bonic plague in the fourteenth century. In a passage from his work On Plague, the fourteenth-century Arabic physician Ibn al-Khatib wrote, “The exis­tence of contagion is established by experience, study, and the evidence of the senses, by trustworthy reports on transmission by garments, earrings; by the spread of it by persons from one house, by infec­tion of a healthy sea-port by an arrival from an infected land” (Arnold 1952). Even though the writer had no inkling of the intermediate role played by the flea and common house rat in the spread of plague, the patterns of spread convinced him that the disease was contagious.