Introduction
The modern scientific medicine has been immensely successful in finding out cures for a large variety of diseases in the last century. As a result, medical scientists as well as practitioners have come to implicitly believe that the advancement of medical knowledge shall continue to be governed by the existing paradigm of scientific medicine. This assumption has been responsible for almost total neglect of philosophy of medicine in the educational curriculum of medical students. However, it is increasingly becoming clear that modern scientific medicine has now entered a new period of ‘paradigmatic instability’. Therefore, it is now a period when philosophy of modern medicine should be reexamined critically. (Kahn, T., Wulff, H.R., Pedersen, S.S. and Rosenberg, R. 1986). This need is also emphasised by the changing perspective of Health in WHO declarations and resurgence in the interest in various traditional/folk medical systems throughout the world. There has been much effort in the direction of evaluating and integrating traditional/folk, alternative/complementary medicine with modern scientific medicine during the past two and a half decade. However, such attempts have made very little headway due to mutual incomprehensibility of the concepts and theories of each other. An understanding of the fundamental philosophies of scientific and other medical systems and their reappraisal is necessary for integration of their concepts and theories as well as of their practices. In the following discussion philosophical basis of modern scientific medicine has been analysed with a view to compare it with that of other traditional medical systems.
ONTOLOGICAL AND EPISTEMOLOGICAL POSITIONS OF MODERN SCIENTIFIC MEDICINE
Empiricism is an epistemological position and realism is an ontological position. In the concepts, theories and practices of modern science, both empiricist and realist trends can be discerned. Since modern medicine is also a scientific discipline, this is true for its concepts, theories and practice also. Before examining the impact of philosophy on modern medicine, it would be worthwhile to discuss briefly the ontological and epistemological questions and problems as they concern the science in general.
Philosophical problems of Empiricism and Realism
Ontology is the theory of being and ontological questions are concerned with existence, reality and the true nature of things. Realism is the ontological position that the external world is real and it exists independent of the human observer. This position also takes the view that the really existing objects, structures and mechanisms of that world stimulate the sense perceptions of human observer. On the other hand, anti-realist position professes complete agnosticism as regard to ontological questions.
Epistemology is the theory of knowledge and epistemological questions are concerned with what can be known about the world and methods of knowledge. Empiricism is the epistemological position that states that ultimately all the knowledge stems from the sense experience. On the other hand rationalism is the position that, besides sense experience, reason is a source of knowledge.
Empiricism on the epistemological level is usually associated with anti-realism at ontological level.
On the other hand, justification of realism on the ontological level requires rationalism on the epistemological level.
The rise of empiricist philosophy in Europe in 17th and 18th century was result of the changed intellectual climate following the ‘scientific’ achievements of men like Kepler, Galileo, Harvey, Newton etc. This school of philosophy is largely associated with philosophers like John Locke, George Berkeley, Auguste Comte and, in this century, the logical positivists of Vienna Circle and their successors have analysed the logical consequences of empiricist thinking. Though there is disagreement on several important points, all the empiricists share the fundamental belief that all knowledge is derived from experience.
Empiricists, although accept the laws of logic and mathematics, assert that logical and mathematical deductions are analytic which means that they do not generate new knowledge, but serve to analyse the existing knowledge. Further, anti-realism of empiricists proves it necessary to redefine the concepts like causality and objectivity in such a way that they do not presuppose any reality beyond observation.
The ontological scepticism of empiricists, though seemingly counter-intuitive, is quite acceptable in advanced science. Scientists are generally concerned with the study of natural phenomena that are not directly observable, by the use of ingenious instruments. Medical scientists have postulated the existence of specific receptors on the surface of brain cells on the basis of sophisticated experiments. It is difficult is say whether such entities ‘really’ exist or they are creations of scientists’ imagination which only serve to organise their ideas. Even medical practitioners depend on sense-extending instruments (e.g. X-ray equipment), detecting instruments (e.g. electrocardiograph) and complicated chemical analysis. They create by such indirect observations, a picture of reality that they can not perceive directly.
Empiricists do not accept the generative theory of causality that implies that causal relation takes place in the external world independently of our observations. They propose the alternative succession (Humean) theory of causality in which idea of causality is explained in psychological terms. This theory points out that if we observe one event followed by second event several times, our expectation of the occurrence of second event after the occurrence of first event increases. The causal relationship is this expectation, a mental habit, which we erroneously extrapolate, to an external world. The succession theory may be refined by analysing in detail the logical relationship between cause and effects. The usefulness of such analysis can be shown in discussion of the causation of disease.
From the empiricist point of view the laws of nature do not tell us what really goes on in the world but their function is the ‘mnemonic reproduction of facts in the mind’ i.e. these laws are simply mental constructions that serve to describe as concisely as possible the observations made.
The term objectivity is used by empiricists in a very restricted sense. The term has ontological implications and refers to phenomenon believed to exist independently of the observer. Since empiricists position denies this interpretation, empiricists equate objectivity with inter-subjectivity. They assert that if exactly same observation is made by two different observers then the observation statement is said to be objective meaning that it is inter-subjective, public or verifiable. This assertion lead logical positivists of this century to formulate a demarcation criterion, which may serve to distinguish those propositions, which are meaningful from those that are not. They proposed a criterion of verifiability according to which only those statements are meaningful which in principle could be labelled as verifiable. However, this criterion leads to quite serious consequences and difficulties:
1. According to this criterion, all attempts to discuss moral issues rationally are considered futile. This nihilistic attitude to moral philosophy is called emotivism.
2. The criterion itself is not verifiable and, therefore, must be regarded as meaningless by empiricist standards themselves. Thus, the criterion is self-defeating.
3. The criterion leads to the classical problem of induction since the criterion may well be applicable to singular statements. However, science is generally concerned with general statements, which can not be verified with absolute certainty by experience alone. The empiricists assert that scientific process starts with observation but the leap from experience which always consists of singular observations, to a ‘law of nature’ can not be logically defended as it can never be excluded that the next observation will prove the law to be false. This logical problem has always vexed empiricist philosophers and despite much effort by logical positivists in this century, it has yet not been possible to logically define the jump from singular observation statements to general theory. Bertrand Russell has simply concluded that ‘induction is an independent logical principle incapable of being inferred either from experience or from other logical principles, and that without this principle science is impossible’.
Karl Popper has been the most influential philosopher of science of this century. He has made very important point that observation is always selective. It needs a chosen object, a definite task, an interest, a point of view, a problem. He asserts that first step in scientific process is not observation but the generation of hypothesis, which may then be tested critically by observations and experiments. The goal of scientific effort is not verification but falsification of the initial hypothesis. As empiricists use criterion of verifiability to distinguish between meaningful and non-meaningful statements, Popper used the criterion of falsifiability to distinguish between those theories that fall within province of science and those that may be labelled as pseudoscience. This thought and the criterion of falsifiability has influenced the modern scientific methodology to a very large extent. However, the criterion of falsifiability, despite its importance from the logical point of view, is not easy to handle in practice. Popper himself has pointed out that there is no such thing as pure observation and, therefore, a scientist who conducts an experiment and contradicts a theory can not be sure whether the theory has been falsified or the observation (or the experimental set-up) was at fault. Further, the biological and medical scientists mostly have to subject their observations to a statistical analysis and the final analysis depends not only on the observations but also on the convention as regards the choice of statistical tests and the accepted level of significance. Thus, Popper instead of solving the problem of induction has, in a sense, tried to bypass the problem. The scientists undoubtedly in many cases try to falsify hypotheses but in many other cases, they try to reason inductively. Medical research papers also contain numerous statistical calculations that reflect inductive reasoning.
Despite the importance of empiricist philosophers’ teaching regarding the importance of empirical evidence, it is obvious that from a purely philosophical point of view the radical empiricism leads to a dead end and creates insurmountable problems. It imposes a view of the world that is quite counter-intuitive. The empiricist belief that all knowledge is derived from experience has not been established up till now to be fully consistent. The empiricist denouncement of realism has been unsuccessful in clarifying many of the philosophical problems. This forced inquiry along the lines of weakening the empiricist position.
Immanuel Kant did not accept the Locke’s idea that mind was originally like a blank sheet of paper. According to him, space and time are preconditions for the perception of something as an object and, therefore, human beings are ‘programmed’ to think in categories of quantity, quality, casualty, possibility, necessity, existence etc. A human being’s picture of the actual world reflects this a priori organisation of his sense perceptions and his actual observations. Kant, is thus, a rationalist asserting that the empirical knowledge is organised according to a priori principles but, like empiricist, he does not accept the possibility of knowledge of things-in-themselves. Contemporary philosophers and psychologists have also given up the idea that the mind was originally a ‘blank sheet of paper’ and they also deny the existence of a thing like pure observation. In medical examples, theory-dependence of observations can quite obviously be demonstrated. However, the role of empiricist philosophy in the development of science, including the scientific medicine, should be viewed in historical perspective. The metaphysical theories of per-empiricist era were far too extravagantly rationalist and realistic. Therefore, it was only natural that empiricists felt that science must start afresh with systematic observations and establishment of the laws of nature. Despite Popper’s assertion that we can never be quite sure about our theories being true, the efficacy of modern technology that is based to some extent on scientific theories, proves beyond doubt that in some areas Popper’s ‘approximation to truth’ has been achieved. It is quite true that the development of modern science is inextricably bound up with empiricist philosophy, but philosophical reflections and the results of modern science suggest that the classical empiricist position is quite untenable. It is more appropriate to accept the:
1. realist point of view on the ontological level that the purpose of science is to explore what really goes on in the world and on the epistemological level, accept existence of pure observations but deny that the observations are the only source of knowledge,
2. existence of causal relationships and deny the empiricist succession theory of causation,
3. view that if one event generates another event through some or the other mechanism (as is quite obvious in some bio-medical situations) then a causal relationship between the two events exists and then these events may be said to follow the laws of nature and
4. the view that causal relationships and laws of nature are objective in the sense that they exist independently of observation.
Though the realist position does not solve the problem of induction, the knowledge of underlying mechanism sometimes makes the problem less troublesome. For example, the general statement that human granulocytes contain glycogen synthetase is not only the result of inductive inference, it is also based on existing theoretical knowledge.
The philosophy of science has been dominated by empiricist thinking for the last few centuries, but during the last few decades, many philosophers (Smart, J.J.C., 1963; Harre., R., 1970; Hacking, I., 1983; Bhaskar,R., 1975) have favoured a realist theory of science which points out that scientific knowledge has both a transitive and an intransitive aspect. Knowledge in the form of a scientific theory should be regarded as a changeable social product, and as such, it is transitive. However, the object of that knowledge that does not depend upon the existence of observer, is intransitive. The importance of this observation is that it reveals the deficiency of different views of science including the medical science. Extreme realists disregard the transitive aspect of scientific knowledge while extreme empiricists disregard the intransitive aspect. It may be proposed that a balanced philosophy of natural science must take into account both the aspects and the relationship between them.
Empiricism and Realism in modern medical thought
Philosophers of ancient Greece and medieval Europe were largely concerned with speculations about the nature of world, purpose of life etc. The Greek and medieval European philosophers were largely realists. In keeping with the such philosophical atmosphere, medical theory in the western world two or three centuries ago, was to a large extent based on mere speculation. The philosophical position of Hippocratic humoral pathological theory describing four ‘humours’ (blood, phlegm, yellow bile and black bile) with different qualities and other similar theories may be described as speculative realism at ontological level and extreme rationalism at epistemological level. From realist position, these systems believed in the existence of an underlying real disease mechanism but being rationalists to an extravagant degree, they also believed that the nature of underlying disease mechanism can be ascertained by pure reasoning alone. It can be pointed out here that the philosophical position of various traditional/folk e.g. Ayurved, Unani) and newer unorthodox (Homeopathy) therapeutic systems can also be shown to be speculative realism and rationalism in varying degrees.
Under the influence of empiricism the philosophers and scientists developed a sceptical attitude towards ontological inquiries and began to assert that one must rely entirely on one’s senses. Empiricist demand for careful observation had some effect on medical thinking as early as 17th century. Thomas Sydenham stressed the importance of clinical observations at the bedside and described a number of disease entities on the basis of their clinical manifestations. In the 18th century, following Linnaeus, the botanists who were also physicians, attempted to classify diseases like plants. These disease classifications were inspired by empiricist thinking as no attention was paid to the mechanism of disease. Being no more than divisions and subdivisions of ill-defined symptoms, such classifications of diseases had no lasting effect on the development of modern scientific medicine A few decades later, medical scientists developed an interest in human physiology. This made them see physiological disturbances where before this, they had only seen anatomical disturbances. This new mode of observation and consequent thought process had profound effect on the disease classification. The interest in physiology lead to establishment of new disease entities also. During the second half of last century, foundations of modern microbiology were also laid down. Identification of infective agent of disease had very significant effect on the philosophy of disease classification for two reasons. Firstly, it became possible for the first time to define a large number of disease entities aetiologically and, secondly, the dogma of universality i.e. one cause results in one disease was further established. This dogma, however, can be shown to be fallacious in the case of most of the infectious diseases, as the bacterium or the virus must usually be regarded as one of the many non-redundant causal factors in the individual patient. The disease classification is still largely a mixture of disease entities defined in anatomical, physiological and microbiological terms. In addition, a number of immunologically defined disease entities are also being established as a result of increasing interest in immunology.
The anatomists, physiologists, microbiologists and immunologists have been working under the influence of empiricist philosophy in so far as they pay great attention to their empirical observations in the laboratory. However, they are unknowingly following the realist philosophical position as they try to discover the underlying mechanism of disease forgetting or ignoring that true empiricist position denies this possibility. This is the underlying but ignored or not clearly understood schism between a realist and empiricist trends in modern scientific medical thinking still persisting today which had historically started in 1830s and 1840s. A highly significant analysis of the medical problems from the empiricist point of view was given by Gavaret (Gavaret, 1840). Gavaret’s ideas were premature for his time and were not given much attention. However, a century later, in 1940s, time was ripe for the revival of his ideas in the form of new critical clinical school. At that time, the combination of new scientific knowledge and new technology resulted in explosive growth of new therapeutic and diagnostic methods which had to be tested critically in accordance with Gavaret’s tenets which may be summarised as following:
1. The Laws of Logic are insufficient for judgement of the effect of a given treatment for a given disease as well as for the ranking of those treatments that are recommended for the same disease according to the degree of their effect.
2. Only the Law of Large Numbers, which is applicable to therapeutic investigations, can solve these two important problems.
3. The death rate obtained by statistical calculations is never a precise and correct expression of the effect of the treatment in question, but larger the number of observations, closer the approximation.
4. A Therapeutic Law, obtained by comparing small number of facts may be so far from truth that it can never be trusted.
5. A Therapeutic Law is never absolute, but must always be expressed as a range. The range decreases as the number of observations increases and its width can be determined by those numbers on which the statistical calculations are based.
6. For determining the preference between two therapeutic methods, the results of preferred method must not only be better but the difference must also exceed a certain limit which depends on the number of cases.
7. When the number of investigations is large and the difference is low which does not reach this limit, it can be ignored as non-existent.
8. The same rules and same conclusions are applicable to the solution of problems connected with the theory of epidemic constitutions.
9. The same rules must be followed to ascertain whether the death rate in a disease varies according to age, sex and location.
10. In investigations of aetiological problems, the Law of Large Numbers only serves to prove the presence or absence of a presumed cause, regardless of its nature. The cause should be determined itself by means of considerations of a different order. This last question is outside the domain of statistics.
The first nine tenets show radical empiricism while in the tenth tenet Gavaret suddenly retreats from this position. Empiricist theme is introduced in first three tenets i.e. doctors should study as many patients as possible and must not base their therapeutic decisions on speculative theories and logical deduction. In other words, they must discard theory and rely on positive facts. Tenets 4 and 5 clearly indicate the empiricist view of law of nature i.e. the demonstration of a law of nature is no more than the demonstration of a regular association between observed phenomena. Tenets 1 to 9 are almost similar to the recommendations of present day statisticians indicating that Gavaret was more than a century ahead of his times. It may also be pointed out that in 10 tenet, Gavaret points out the limitation of statistical approach and points out that statistics only serve to establish the presence or absence of a causal factor, regardless of its nature. He also seems to disapprove of the empiricist view of causality and assumes that a causal relationship is more than a regular succession of events and there is room for ‘considerations of a different order’.
Vast majority of Gavaret’s contemporary doctors who were interested in science ignored his views and continued to explore the mechanisms of disease, in the hope that the accumulation of enough such knowledge would enable doctors to deduce the correct treatment in the individual patient by means of the ‘Laws of Logic’. It is thus clear that the vast majority of doctors at that time were realists but accepting and applying the empiricist tenets of observations and experimentations.
Current medical thinking
The contemporary medical thinking is also pervaded by both realist and empiricist approaches. For example, a modern lecture on a particular disease describes the observed symptoms or signs of the disease, gives a theoretical account of the underlying disease mechanism that fits a multitude of carefully executed experiments and then concludes the logical treatment of that particular disease. It may be pointed out that for a disease, results of individual investigation are usually numerous figures that have been subjected to statistical analysis following the empiricist approach. However, these statistical truths are not regarded as an end in themselves. Rather, these are thought of as only a means to the establishment of a coherent theory, which is believed to reflect the reality behind the observations. This view of science has been labelled realism under empirical control (Wulff, Pedersen & Rosenberg, 1986). This current view differs markedly from that of radical empiricists like Gavaret and his modern followers whose sole aim is to formulate the statistical ‘laws of nature’ that may serve to predict future occurrences. Thus, the current medical thinking agrees fully with realist approach that medical knowledge, to a large extent, depends on acquisition of more knowledge about the functions of human body in health and disease. However, it also believes in the great need of empiricist statistical approach in such matter.
In the science in general, this mixture of realism and empiricism has lead to the recognition of distinction between pure science, technology and technique. In the modern medicine also similar distinction between biological medicine (the scientific level), clinical medicine (the technological level) and clinical practice (the technical level) has been recognised. Members of the medical profession engaged in the biological medicine (e.g. basic research in the laboratory) are medical biologists. Those engaged in clinical medicine (e.g. testing of new drugs) are clinical researchers while those engaged in clinical practice (e.g. examination and treatment of individual patients) are medical practitioners.
Medical biologists, just like physicists, seek true knowledge and their philosophical position is that of realism under empirical control. Though realism underlies the biological medicine, it should be pointed out that the biological variation exists at every level and this makes it impossible to make exact predictions in the individual case. The prognosis of the individual patient must always remain a statistical truth. Further, the course of a disease must usually be regarded as the result of a persistent interaction between the inner mechanics of body and the environment. Therefore, an exact prognosis requires extensive biological knowledge as well as full control of the stimuli from outside. There are numerous examples in the past of the introduction of wrong or worthless diagnostic and therapeutic methods due to unwarranted self-confidence on the part of biological scientists. These have clearly demonstrated that deductions from biological theory are often unreliable and that the techniques used in clinical practice must be tested empirically.
The controlled therapeutic trial for the comparison of two treatments is the prototype of clinical research. The statistical result, which is a typical example of inductive reasoning, is what Gavaret calls a ‘therapeutic law’ and it serves a predictive purpose. Clinical researchers also test diagnostic methods according to similar principles. In this way the philosophical position of clinical researchers may be described as empiricism on the methodological level. They are not empiricists in the original philosophical sense as they do not accept the ontological agnosticism of Hume and the logical positivists. They fully accept that we know quite much about disease mechanisms but they emphasise the incompleteness of biological knowledge and impossibility of precise clinical predictions due to biological variation. The clinicians holding these views represent the critical clinical school, which revived the ideas of Gavaret in 1950s and 1960s. Further, it has been pointed out by many workers that clinical practice must not be regarded as applied biological medicine and it is necessary to adopt empirical approach for the solution of clinical problems.
An important difference between realism under empirical control in biological medicine and methodological empiricism in clinical research should be noted. The statistical methods are also used in biological medicine but the end-product is always a theory considered to be a picture of reality, which may be true or false. On the other hand, end-product of statistical methods in clinical medicine is always a statistical ‘law of nature’ which serves to predict future events.
Thus it may be pointed out that empiricism as a philosophical position is not tenable as, clearly, it is possible to reach some insight into the working of nature. However, the realist belief that medical theories will ever form a completely true and exhaustive picture of reality is also quite naive.
CONCEPTS AND THEORIES OF MODERN MEDICINE
The modern scientific medicine as known today may be considered to have truely originated in the last century when medical scientists began to systematically investigate the structure and function of the human organsim 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 as 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 the 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 purely a 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 i.e. the disease is the sum of the abnormal phenomena displayed by a group of living organisms in association with a specified common characteristics by which they differ from the norm for their species in such a way as to place them 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 the problem of deciding 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 diseas 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 sickness or ill health as fairly 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 implied in biological theory of disease also 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. It is the people who seek medical help when they feel ill and the demonstration of a biological (mechanical) fault in the human organism is of 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 for self-reflection and personal capability to decide the goal of life. Eric Cassell ( ) has pointed out that an understanding of the patient’s suffer ing 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 personhood, including 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 is now being 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 syndromswhich can be defined only by the clinical pictures of patients as not much is known about their underlying mechanisms. At the begining 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 which made them see physiological disturbances where before they had only seen anatomical lesions. This new mode also profiundly 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 accroding to the species of infective agent. This was a very important phase in the history of disease classification since 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 and immunologically defined disease entities are also being established. However, the nomenclature and classification of disease is still largely a mixture of disease entities defined in anatomical, physiological and microbiological terms. With the development of disease classification and it use, two contrasting attitudes towards the disease entitiy have developed among medical professionals which 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 which 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 taken in medicine since no two sick people can ever be completely identical as regards to their clinical pictures and the underlying causal mechanisms and, therefore, 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 and 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 recognize natural kinds and this ability is of fundamental importance to scientists though the sophiticated nature of their activities requires that they learn to recognize 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 and each such ‘natural kind’ constituded a clinical syndrome which was given a name i.e. a disease entity was established. Though such syndromes (disease entities) were never well defined, 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 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 entity
In contrast to Lockean nominalistic attitude, conversations between 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 haveing 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 idividual 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 unchangable 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 which are copied, rather unsuccessfully, by the patients seen by the clinicians on their wardrounds. Though it it is true that doctors do not really believe that diseses are domons that attack people or that the doctrines of Platonic philosophy are true, they, nevertheless, tend to overlook that the nomenclature and the classification of disease is man-made and they assume unreflectingly 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 specialized investigations to establish the real disease in the patient. However, the existence of a real disease entity in an individual patient can neither philosophically nor practically be established. The Platonist attitude also misses the point that disease classification serves a therapeutic rather than a preventive purpose. Traditionally, most of the diseases are defined pathogenetically and 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) which 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 which may well be statistically significant, but do not point to any measure to prevent the disease with any degree of certainity 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 and it may also be regarded as a pathogenetic cause producing the disease inside the body. Therefore, micobiologically 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 one. It is the general assumption in modern medicine that the description of the typical case of a disease given in a medical textbook being the ideal and real description of that disease entity. It is becoming increasingly clear by the studies of medical sociologists that such assumption is quite untenable.
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.
