134 all students. I do not accept the view that an understanding of the ways of science should be offered only to the top minority of medical students who are going on to be investigators and that it is "wasted" on the rest who should simply be encouraged to learn "the stories",


(2) Knowledge of


Department of Medicine, McMaster University, Hamilton, Ontario*

It is generally accepted that medical students should learn those stories from the basic sciences which enable medicine to be rational. But there are several reasons why science as an explanatory activity has much more to offer, particularly if the views


of Popper


accepted. Unfortunately


improves practice,

the immunology of which was only worked out many years later; the management of a blue or breathless pa. tient is improved by a firm grasp of the classic stories of respiration, circulation, and blood; the management of acute renal failure advanced dramatically thirty years ago when clinicians realised that the kidney is an organ of regulation rather than simply of excretion. Obviously one could multiply examples. It so happens that the development of good stories usually also has the effect of making medicine more quantifiable and therefore less uncertain. However,measurement without purpose is neither good science nor good medicine.


of the nature of science is only accidentally acquired in traditional schools and current forces may well weaken its chances in newer schools. Some of the criticisms levelled at modern medicine which may be attributed to excessive science are misdirected. There is too little science, not too much.

The need for medical students



learn these stories is

generally accepted-so generally accepted that they are usually required to learn them before the study of medicine itself. I criticise this traditional requirement for

MY title is chosen to distinguish between the content of science, which I shall call "the stories of basic science", and the nature or processes of science. These processes are admittedly not well understood, but I want to argue that if one takes Popper’s view ’the relevance of science to clinical medicine is much closer than is generally

four more

First, for many students the stories are interesting and easy to learn as part of medicine,


rather than as a preliminary. Secondly, the firmness of grasp required if the stories are really to become deeply ingrained and usable (as opposed to recallable) can best be obtained if acquisition and use of the stories occur together. Thirdly, the stories the basic scientists think are important are often different from those the clinician needs. Fourthly, the tradition perpetuates the feeling that clinical medicine, although it uses the stories of science, is otherwise not scientific.


Popper’2 maintains that science is above all an explanatory activity consisting in imaginative leaps or conjectures put in forms which make them amenable to refutation. He differs from the official or classical view in denying the role of induction and in emphasising that the characteristic of a scientific statement is that it is refutable, not that it is verifiable. This is not the place to attempt an exegesis of Popper, a task brilliantly performed by Magee3 and Medawar45 but the following passage conveys his flavour and indicates why one should not be content to look upon medical science as a structure of knowledge founded on the so-called basic sciences:

(3) The ability to sustain one’s own education requires the ability to assess evidence by the scientific approach.-Clearly, the stories I have just referred to change and need bringing up-to-date. It is reasonable and practical that doctors should regularly replace the worn-out stories with new ones by reading new editions of textbooks or attending refresher courses, and so on, In so doing, they use their brains as the equivalent of

"Science does not rest on solid bedrock. The bold structure of its theories arises, as it were, above a swamp. It is like a building erected on piles. The piles are driven down from above into the swamp, but not down to any natural or given base; and if we stop driving the piles deeper, it is not because we have reached firm ground. We simply stop when we are satisfied that the piles are firm enough to carry the structure, at least for the time being".1 IMPORTANCE OF SCIENCE IN MEDICAL EDUCATION

My reasons for regarding science in one or other sense as an important part of medical education are as follows :

(1) Cultural.-Although ability to use this powerful not essential to a provider of health care, I believe that an opportunity of attaining it should be offered to

tool is

*Present address: Department of Medicine, Du Cane Road, London W12 0HS

"basic science"

—Ibelieve that medicine is on the whole better when it is based on a good (well-tested) biological story-has a "scientific rationale". Here are a few examples of such beliefs. The management of infectious disease depends upon the stories of microbiology; blood-transfusion became safe as a result of the postulate of blood-groups,

Royal Postgraduate Medical School, ’

loose-leaf notebooks, parts of which are to be torn out and replaced with new material at intervals. However, I believe this practice is unsatisfactory unless one also can change the stories oneself, or, at least, appreciate how the stories can be changed. Of course, one cannot change stories for oneself across the whole field of medicine and science. Even the professional scientist becomes aware of advances in fields outside his own by skimming the reviews, leading articles-and the summaries of the papers-in general scientific and medical journals, and he may accept the new stories on trust. But his guard is higher and he is confident that he could, if necessary, follow the steps of discovery himself. (4) Much of the "art" of medicine is closer to science than is generally realised.-Just as the usual or official view is that science is an inductive/deductive process, so medicine is

usually taught as if it too is




ductive process; and students are taught to "take a full history and do a complete physical examination" (i.e., observe), and then think of a differential diagnosis (induction), and then test it by some appropriate investigation (deduction). I have come to feel that this is bogus. Just as Medawar6 asked "Is the scientific paper a hoax?" I would be prepared to ask of the case-record we tradi-

tionally require: "Is it a hoax?". Perhaps in attempting to make the point, I might go too far but I am prepared to assert that in only a few situations does the clinician settle down to "observe"-that is, to collect information with an open mind until he has completed the history and examination. I really believe that all doctors start thinking of possibilities as soon as they meet a patient. In other words, they start making hypotheses. Good technique in history-taking, physical examination, and the choice of investigation is dominated by the need to generate hypotheses quickly and test them critically rather than wasting time and money collecting information. I suspect that both teaching and practice would be improved if this behaviour were formally recognised, explored, and encouraged in clinical teaching as is thoroughness in the usual sense. Obviously students must learn the elements of clinical technique, but setting out to become a doctor by acquiring skill in clinical techniques may be as misguided as setting out to be a scientist by acquiring skill in laboratory techniques. The modern patient’s chart, written—or, worse, dictatedafter taking the history is a hoax in that it misrepresents not only what went on but what ought to have gone on in the mind of the houseman. The seemingly erratic handwritten notes of an experienced clinician in a hurry is a truer record of both. In suggesting that the early generation of hypotheses and their examination is good medicine I recognise a risk and a problem. The risk is that I may be taken as countenancing slipshod practice; this risk I accept. The problem is the development in the learner of the knowledge necessary to generate hypotheses and examine them at the same time as one encourages the clinician’s mental habits. This seems to me the central problem in teaching the practice of medicine, compared with which curricular manipulation of the basic sciences is child’s play. Of course, most students get there in the end-usually after they are qualified-but I feel it takes too long and, as teachers, we too often teach what we think we should do instead of what we do. To use Popper’s’ metaphor we pay too much attention to the bucket function of the mind and not enough to the searchlight. We confuse the art and science of medicine. As usual, Medawar hits the mark; "the clinician ... (having avowed that medicine is a marriage between art and science) spoils everything by getting the bride and groom confused. It is the unbiased observation, the apparatus, the ritual of factfinding and the inductive mumbo-jumbo that the clinician thinks of as ’scientific’, and the other element, intuitive and logically unscripted which he thinks of as a ...

’creative art’."

(5) Doctors should use words the way scientists do.The way scientists use words is well put by Popper when he points out that most scientific statements should be read from right to left rather than from left to right. To take Magee’s example3 " ’a di-neutron is an unstable system comprising two neutrons’ is a scientist’s answer to the question ’what shall we call an unstable system comprising two neutrons?’, not an answer to the question

’What is a di-neutron?’. The word ’di-neutron’ is a handy substitute for a long description, that is all; no information about physics is to be gained from analysing it." To the scientist "di-neutron" is a word, not a thing. To use philosophical jargon he is a nominalist not an essentialist. I believe the same should be true of medicine. The labels we use in medicine should be read from right to left, not from left to right. Much bad practice and equivocal research stems from a belief that an "essence" lies behind medical terms. I suspect this is a heritage from the primitive need to believe in external agents, spirits, humours as ways of explaining illness; a belief kept going by the discovery of germs. Such a belief may account for the discomfort doctors evince when faced with the choice of calling some condition a "syndrome"

"disease". These matters may seem intellectual and arid. Attempts to discuss them always irritate medical audiences, who regard them as semantic (this adjective having acquired a pejorative taint). But it is no mere intellectual matter when a patient who has had a label applied by a doctor who uses it in one sense is treated by another doctor who uses the label in a different sense. or a




SCHOOL? would be "accidentally, not purpose-


My brief answer fully". In traditional schools, the acquisition of scientific understanding comes accidentally through a variety of means. Firstly, from lectures--or rather from lecturers. It is a poor medical school indeed without at least one scientist who in his lectures conveys the nature, the excitement, and the approaches of science. Usually, such people are in the basic science departments. Secondly, in laboratory exercises. I doubt that the perception of science is enhanced other than acidentally by these exercises (many of which are coyly inductive/deductive in their arrangement). Nevertheless, many students meeting a particular problem and a particular instructor or scientist become switched on to science. Thirdly, through electives. In Britain these at best take the form of an honours year after the preclinical period. However, this opportunity is usually afforded only to an elite minority whose academic performance and subsequent careers reinforce the feeling of the majority that science is not for them nor for their sort of medicine. I had expected the situation to be better in North America where most medical students have three years of basic science at university before entering medical school. Unfortunately, many of them are only stuffed with stories. tYhat about Newer Medical Schools?

Here I have


Increased pressures for "rele-

vance", to curtail curricula, and to produce more practitioners ; disenchantment with the formal courses and laboratory exercises in basic sciences-these have combined which

to remove

many of the occasions and


accidental opportunities for the provided of science and have often failed to replace appreciation them with anything else. Admittedly, the modern specialist can tell the stories about the way his bit of the body works--in many instances better than the generalpurpose physiologist or biochemist-but he is less likely even


try and interest the students in the scientific origins of these stories. The current pressures for early clinical exposure and more relevance are reactions against the excesses of the Flexnerian revolution. However, there is a danger that this reaction with its understandable wish to harness the vocational drive of the students may limit the demands they make of science and scientists. There is a little-used word which nicely expresses what I fear-banausic, "suitable for a mere mechanic; illiberal". Unless science is more fairly treated, the reaction may have the unfortunate effect of weakening the scientific influence in medicine because of a false association of science with technology and a false antithesis between science and humanity. There is a danger that rather than putting right the undesirable consequences of the Flexnerian revolution we shall return to the pre-Flexnerian era. There may be a change in that knowledge of the stories of the more groovy sciences such as molecular biology may be required instead of the stuffy old ones such as anatomy, but that may be all. Special effort to promote the interest of students in science is needed in face of the demand for clinical relevance. I believe the best hope lies not in a return to the traditional methods of instruction in basic science courses but in the personal example of the scientists both "basic" and "clinical" who should insist that an appreciation of science must be an objective for all students. There are many ways in which this objective may be achieved; but I am sure that, just as it is essential for the students to meet doctors behaving as doctors, so it is essential for them to meet scientists behaving as scientists. The student and the scientist must be brought together for a grander purpose than the passive transfer of acceptable stories. to

WHAT? One does not have to be a renegade or a Luddite to admit that people such as Illich9 have some grounds for criticising the overenthusiastic application of technology in medicine. Those who side with such critics may well attribute any such shortcomings of the medical profession to too much scientific education and there is definitely an antiscientific ring to many of the voices arguing for reform in medical education. I believe that these criticisms are mistaken and that the hope of progress lies not in an attack on the dominant role of science in medical education but a recognition that it is too weak. SO

Occasional Survey MORTALITY FROM LUNG CANCER AND CORONARY HEART-DISEASE IN RELATION TO CHANGES IN SMOKING HABITS* NICHOLAS J. WALD D.H.S.S. Cancer Epidemiology and Clinical Trials Unit, Department of the Regius Professor of Medicine, Radcliffe Infirmary, Oxford OX2 6HE

Changes in the type and quantity of cigarettes smoked in the United Kingdom from 1956 to 1971 are compared with changes in the death-rates due to lung cancer and coronary heart-disease (C.H.D.) from 1956 to 1973. Associated with a change to filter cigarettes there has been a decrease in lung-cancer mortality among men aged less than sixty years despite little change in the number of cigarettes smoked. In contrast, lung-cancer mortality has increased in women along with their cigarette consumption. C.H.D, mortality has continued to increase in both sexes, but to a greater extent in women. These changes are consistent with the hypothesis that, in tobacco smoke, tar is the principal ætiological factor in lung cancer, whereas car-


bon monoxide or other gaseous constituents in the development of C.H.D.




MORTALITY from lung cancer and coronary heart-dis(C.H.D.) is associated with cigarette smoking.’-31I have examined changes in mortality from these diseases in relation to altered patterns of cigarette smoking in the United Kingdom, and attempt to interpret the changes in mortality recorded. ease


The total annual consumption of manufactured plain and filter-tipped cigarettes in the U.K. from 1920-71 was obtained

grateful to many people at McMaster and elsewhere for their was finally written while I was a Josiah Macy, Jr. Foundation Faculty Scholar, 1975-76, at the Royal Postgraduate Medical School, London. I


criticisms and suggestions. The essay

REFERENCES 1. Popper, 2. Popper,

K. R. The Logic of Scientific Discovery. New York, 1959. K. R. Conjectures and Refutations: The Growth of Scientific Know-

ledge. London, 1962. 3. Magee, B. Popper. London, 1973. 4. Medawar, P. B. The Art of the Soluble. London, 1967. 5. Medawar, P. B. Induction and Intuition in Scientific Thought. London, 1969. 6. Medawar, P. B. Is the Scientific Paper a Fraud? in Experiment: A Series of Scientific Case Histories first Broadcast in the B.B.C. Third Programme. (edited by David Edge). London, 1964. 7. Popper, K. R. Objective Knowledge; An Evolutionary Approach. London, 1972. 8. Concise Oxford Dictionary of Current English (edited by Henry Watson and F. G. Watson). London, 1929. 9. Illich, I. Medical Nemesis. London, 1975.


Fig. 1-Annual consumption

of manufactured

plain and filter dprettes ill

the U.K.

"Presented in part at the annual meeting of the Society of Occupational Medicine, September, 1974, and at the 3rd World Conference on Smoking and Health, New York, 1975.

Basic science, science, and medical education.

134 all students. I do not accept the view that an understanding of the ways of science should be offered only to the top minority of medical students...
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