Concepts of modern medicine

CONCEPTS OF SCIENTIFIC MEDICINE
The modern scientific medicine as known today may be considered to have truly originated in the last century when medical scientists began to systematically investigate the structure and function of the human organism in its condition of health and disease. At that time, the break with previous traditions had caused considerable paradigmatic unrest, which had lead to much philosophical discussions in medical literature. However, towards the end of the last century, it came to be generally accepted that medicine was a branch of natural science and that the disease process should be examined in anatomical and physiological terms. This view lead to general acceptance of the biological theory (mechanical model) of disease forming the most important component of the paradigm of medical thought. Therefore, the most important concepts of modern scientific medicine are related to the questions of disease or illness in contrast to health and to the question of disease entity.

Illness and health are important medical terms as the aim of all medical activity is to eliminate illness and preserve health, but they are also important words in the ordinary vocabulary of any language. The medical practitioners tend to define these concepts in biological or mechanistic terms whereas these words in the ordinary language usually refer to the subjective feelings of the individual person. On the other hand, disease terms almost exclusively the medical ones. The disease terms have no precise meaning except in the context of medical science.

Biological theory (mechanical model) of disease
Successive generations of medical scientists have developed the biological theory of disease according to which disease is regarded as a fault in the 'biological machine' i.e. the human organism and, therefore, it is also called the 'mechanical model'. The philosophical position of this theory is that of biological reductionism i.e. it reduces the human beings to biological organisms and human medicine to a branch of biology. The theory assumes that if full specifications of the structure and function of human organism are known then it would be possible to establish in each and every case whether that human being is ill or healthy. The question of health, illness and disease is considered to be a purely biological question and not a question of the feelings or personal norms. The theory totally disregards such concepts as 'vital principle' or 'the soul'.

Concept of normality
It is quite obvious that complete specifications of the human organism are not available to medical science. This problem of specification is usually solved by resorting to the statistical concept of normality. However, it is quite unsatisfactory to equate health with statistical normality since it invites circular arguments. In view of this, it has been pointed out by various workers that biological concept of health presupposes a non-statistical biological definition of health or normality. Workers like Christopher Boorse, Alf Ross and G. Scadding have suggest that the biological organism is healthy if its body functions with atleast species-typical efficiency i.e. it functions according to the normal plan for the species. The species-specific design is regarded as the typical hierarchy of interlocking functional systems that support the life of an organism of that kind. Disease is regarded as a deviation from the typical species design. This means that the disease is the sum of the abnormal phenomena in association with a specified common characteristics displayed by a group of living organisms by which the group differs from the norm of the species. The difference from the species normal places the members of the group at a biological disadvantage.

The problem of threshold
The adoption of the biological yardstick of the state of health in the form of species-design or the normal plan for the species creates an intriguing problem. This yardstick requires prior decision as to how large the deviation from this species design should be taken to identify the illness condition. Scadding ( ) has conceded that the distinction between health and disease may require the insertion of carefully chosen, but more or less arbitrary, quantitative statements about the magnitude of deviation from the mean of normal values that will be regarded as abnormal. Medical professionals tend to view sickness or ill health as an obvious phenomenon defined as a temporary and easily recognisable departure from the natural state of health. However, it is gradually being realised from the experience of extending health services in Great Britain and Denmark that values of species normal for defining health or ill health are dynamic and not static. The experience has shown that the disease threshold falls when health service expands. This strongly suggests that the threshold of health and ill health depends on environmental and socio-cultural conditions also and a purely biological concept of health and disease fails to encompass all their aspects.

The problem of subjectivity of illness
The kind of biological reductionism that is implied in biological theory of disease leads practitioners of modern medicine to ignore their patients' subjective symptoms and regard them as secondary phenomena rather than the necessary constituents of the concept of disease. It should be kept in mind that the primary concern of clinical medicine is subjective disease and subjective health. People seek medical help when they feel ill. The demonstration of a biological (mechanical) fault in the human organism has no clinical importance unless it affects the well-being of the person concerned or serves to predict that the person's well-being will be affected some time in the future. Medical sociologists have shown that the subjective feeling of illness, or disease condition is again largely dependent on a variety of socio-cultural aspects.

While accepting the basic relevance of biological concept and in view of the failures of giving a subjective concept of disease, medical professionals have been forced into a deeper analysis of the concept of species design. Boorse and Ross ( ) have accepted that the species design concept has teleological overtones and a hierarchy of functions may be imagined, each of which serves a higher-level goal or telos. However, this thought process raises the question of the ultimate goals, which seem impossible to define in scientific terms. These highest-order goals are indeterminate and must be determined by a biologist's interests and, therefore, the concept of health and disease as value-free biological states. Further, purely biological approach seems to be insufficient in case of human beings as it ignores their subjective feelings, self-awareness, capacity of self-reflection and personal capability to decide the goal of life. Eric Cassell ( ) has pointed out that an understanding of the patient's suffering is not the same as knowledge of the character of disease and the side-effects of the treatment. Casswell proposes that human suffering can only be understood by taking into account all the aspects of the existence of a person. It has to include the lived past, the family's lived past, culture and society of the person, the body, the unconscious mind and the hopes of the future.

Thus, it has to be realised that the prevalent biological (mechanical) concept of health and disease is too narrow and the meaningful concepts of health and disease might transgress the bounds of scientific medicine.

Concept of disease entity
Until the end of 18th century, doctors could only classify their patients according to the clinical pictures and made diagnoses like dropsy, phthisis, diabetes, typhus etc. Even today, the disease classification comprises of many clinical syndromes that can be defined only by the clinical pictures of patients as not much is known about their underlying mechanisms. At the start of 19th century, doctors began to do routine autopsies and gradually the idea of identifying diseases with anatomical lesions became established. This had tremendous impact on medicine and even today, the majority of disease names are borrowed from the terminology of morbid anatomy e.g. gastric ulcer, myocardial infraction etc. A few decades later, doctors developed interest in human physiology that made them see physiological disturbances where before they had only seen anatomical lesions. This new mode also profoundly affected the disease classification and led to the establishment of new disease entities e.g. arterial hypertension. During the second half of the last century, foundations of modern microbiology were laid and patients with infectious diseases were reclassified according to the species of infective agent. This was a very important phase in the history of disease classification. For the first time, it became possible to define a large number of disease entities aetiologically and the dogma of unicausality (one cause - one disease) was further reinforced. In recent years, medical scientists have also become interested in immunology. These days immunologically defined disease entities are also being established. However, the nomenclature and classification of disease is still largely a mixture of disease entities, that are defined in anatomical, physiological and microbiological terms. Two contrasting attitudes towards the disease entitiy have developed among medical professionals with the development of disease classification and its use. These may be termd nominalist attitude and the idealist attitude.

Nominalist concept of disease entitiy
The philosophical position of nominalism is that a universal (e.g. a disease) is a name (nomen) which is attached to abundle of particulars. In medicine the idea has been expressed by the dictum attributed to Rousseau: 'there are no diseases, only sick people'. According to this view, disease names may be regarded as labels attached to groups of patients that resemble each other in those respects, which are considered medically important. This attitude stresses the point that disease classification is a man-made classification of individual patients, which was required in order to classify clinical knowledge and experience.

The pure nominalistic attitude can not be undertaken in medicine. Since two sick persons can never be identical as regards to their clinical pictures and the underlying causal mechanisms, classification and nomenclature would have to be arbitrary. However, Lockean version of nominalism also stresses the point that our classifications of natural phenomena are not arbitrary, as they must be moulded on the realities of nature. It further points that the particulars constituting a natural kind are grouped together and given a name. The particulars constituting a natural kind are considered to resemble each other in real essence in Lockean terminology. Quine ( ) believes that man has innate capability to recognise natural kinds and this ability is of fundamental importance to scientists though the sophisticated nature of their activities requires that they learn to recognise qualities which are not directly observable.

The doctors had started to classify patients according to their directly observable clinical characteristics and had found that some patients resembled each other in a number of aspects. Each such 'natural kind' was supposed to constitute a clinical syndrome and was given a name i.e. a disease entity was established. Though such syndromes (disease entities) were never well defined, the authors of medical textbooks took to describing the 'typical cases' of each disease. The clinicians began to diagnose these diseases when their patients resembled the typical cases. The purpose was inductive as clinicians expected that their patients, within the limits, would have the same prognosis and respond to the same treatments as the standard cases in the medical textbooks. Later, these clinical diagnoses were replaced by others which were defined on pathogenetic or aetiological levels as it was found that these new disease entities permitted more precise predictions and facilitated the development of specific treatments. However, the new disease entities were less homogeneous on the clinical level and for this reason, a multitude of refined diagnostic methods had to be introduced.

Idealist (Platonist) concept of disease entities
In contrast to Lockean nominalistic attitude, conversations between the members of medical profession reflect a very different attitude towards disease entity suggesting that the diseases are 'things' which exist in themselves and which are discovered by medical professionals. Diseases are talked of as if these are some sort of demons, which attack the people and cause suffering by manifesting themselves in the persons having been attacked. Interestingly this alternative view of the status of disease entity is also found in sophisticated analyses of clinical thinking. Feinstein ( ) writes that illness in the individual patient is the result of an interaction between a disease and a host. Such formulations confirm to Plato's position that universals are divine ideas which are real, eternal and unchangeable whereas particulars are merely transitory reflections of these ideas.

The particular disease, which according to Feinstein interacts with a host, may thus be interpreted along the Platonist idealist philosophy to represent an 'idea' whereas the illness of the individual patient is represented as the mere reflection of the idea. The typical cases described in medical textbooks are thought to be like Platonic ideas that are copied, rather unsuccessfully, by the patients seen by the clinicians on their rounds of wards. In fact, doctors do not really believe that diseases are demons that attack people or the doctrines of Platonist philosophy are true. Nevertheless, they tend to overlook the fact that the nomenclature and the classification of disease is man-made. They assume without reflection that somehow the disease entities have an independent existence.

The unreflecting Platonist view of the nomenclature and structure of the classification of disease implies that it can not be improved. Further, it is obviously more suited to hospital practice than to general clinical practice since it requires a multitude of highly specialised investigations to establish the real disease in the patient. However, the existence of a real disease entity in an individual patient can be established neither philosophically nor practically. The Platonist attitude also misses the point that disease classification serves a therapeutic rather than a preventive purpose. Traditional definitions of most of the diseases are pathogenetical. Medically prescribed interference at that level serves only to repair the disease damage without telling anything about the method of its prevention as we know very little about the aetiological causal factors (environmental or genetic) that elicit the disease process. In general, it can be imagined that the complex of aetiological factors which starts off the disease process differs greatly amongst patients and the hope of prevention of pathogenetically defined disease by some single measure is quite unfounded. For instance, all the efforts of epidemiologists to explore the complex aetiology of myocardial infraction have ended in finding a number of so-called risk factors. These may well be statistically significant, but do not point to any measure to prevent the disease with any degree of certainty in the individual person. On the other hand, infectious diseases may be regarded as both aetiologically and pathogenetically defined since the microorganism may be ragarded as an aetiological factor representing the external cause of the disease. The microorganism may also be regarded as a pathogenetic cause producing the disease inside the body. Therefore, microbiologically defined diseases are ideal for both preventive and therapeutic purposes and fit quite well the Platonist point of view. Since microbiological definition of disease entities has gained much importance in modern scientific medicine in recent times, the unreflecting Platonist attitude has also been implicitly accepted by medical professionals. Another important consequence of Platonist attitude has been that doctors tend to ignore or underestimate the temporal and geographical variation of the spectrum of illness because the world of ideas of Plato's philosophy is a static world. The assumption that the description of the typical case of a disease given in a medical textbook is the ideal and real description of that disease entity is untenable. This fact is becoming increasingly clear due to the studies of medical sociologists.

The above discussion points out that the philosophical problem underlying the contrary nominalist and idealist views of disease entities is the age-old dispute about the universals. Platonistic essentialism correctly underlines that any classification of natural phenomena e.g. disease must reflect the underlying realities of nature. However, it ignores the fact that the classification must also depend on our choice of criteria and that this choice reflects our practical interests and the extent of our knowledge. On the other hand, nominalism correctly stresses the human factor i.e. the individuality of patient but the extreme nominalism overlooks the fact that disease classifications are not arbitrary but must be moulded on reality as it is. It has been suggested that the Lockean theory, which combines both the views, may be particularly suited for the analysis of disease entities and disease classification.