Cause in medicine, says Halliday, has usually been regarded in one of two ways; and he calls them the “mechanismic” and the “biological”.
Mechanismic cause.
The word mechanism refers to a system of mutually adapted parts working together as a machine. Given the requisite preceding movement, the ensuing movement follows necessarily upon it, provided the machine is in working order. During the last three centuries, knowledge of the human organism in terms of mechanism increased progressively and the organism came to be regarded as if it were in actual fact a machine.
If it failed to function properly, the cause of the breakdown was similar to that of a machine that is, a fault in one or more of the component bits and pieces. The primary concern of medicine was to identify the fault, which might be viewed by any technique for example, gastric ulcer, a structural fault; acidosis, a chemical fault; or hypertension, a physical fault and to take appropriate action by interfering with the mechanism.
Some of the implications of mechanismic aetiology Halliday summarized as follows: (1) The human organism is a machine composed of mutually adjusted parts working together. (2) Illness corresponds to breakdown in the machine. (3) The cause of illness (provided the patient has adequate food, air and water) is some thing wrong a fault, disease, lesion, imbalance, or abnormality in one or more of the parts. (4) Medical action is confined to interfering with the mechanism by what is known as the appropriate treatment.
This mechanismic attitude has, of course, brought great advances. The criticism of it is not so much that it is wrong as that it is not enough. In particular it gives little or no guide to action in the prevention of disease, for it is concerned with how a patient is ill rather than why he is ill. One might add that while few doctors now take a purely mechanismic view, most patients do, hence the very great difficulty of giving them any reasonable explanation of functional symptoms.
Say what we will, the patient believes there must be a fault in the mechanism somewhere “the cause” and an appropriate means of dealing with it “the cure”. One might also point out that the mechanismic idea of disease allows of no definition of health other than the absence of disease, which is plainly inadequate, for there is a great difference between “no disease” and health.
Biological cause
Halliday explains what he calls the biological idea of cause as follows. “Illness is regarded, not as a fault in the parts but as a reaction, or mode of behaviour, or vital expression of a living unit in response to those forces which he encounters as he moves and grows in time. Cause is therefore twofold and is to be found in the nature of the individual and the nature of his environment at a particular point in time.” The environment, the totality of exterior circumstances, may be investigated by a variety of techniques physical, chemical, bacteriological, psychological and so on and in this way split up for convenience into separate components which we may call factors.
That an aspect of cause is found in the individual person may not at first sight seem to be obvious. It may be illustrated by pointing out that when two persons encounter the same environmental factor the behaviour of each depends on his characteristics. Suppose, for instance, that a weight of 2 st. falls equally on the legs of a man aged 30 and of his father aged 80. The son will probably develop a superficial bruise, and the father a fracture of both legs. Two men swallow water containing virulent typhoid bacilli. One who gives no previous history of typhoid fever responds ten days later by a morbid reaction whose features include fever, prostration, diarrhoea, etc. The other two does give a history of previous enteric fever, shows no evident morbid behaviour. When an SOS is broadcast several million people may be quite unaffected, while one man falls down in a faint. In each of these imaginary but quite possible examples the environment factor was certainly not the whole cause. As aspect of cause was present in the persons affected.
Some of the implications of biological aetiology were summarized by Halliday as follow: (1) The human organism, although composed of parts, may also be regarded as an integrated unit or living person. (2) Illness represents a vital reaction of a person to factors of the environment which he meets as he moves in time. (3) The cause of illness is therefore twofold certain characteristics of the person and certain factors of the environment. (4) Medical action is concerned primarily with measures designed (a) to alter or prevent characteristics of the person known to be causal and (b) to alleviate or remove factors of the environment known to be casual.
This biological attitude is, as Halliday points out, a sine qua non for effective prevention of disease and may be very important in treatment. One might add that it does make possible a reasonable explanation of functional symptoms, the reaction of a particular personality to factors in the environment, and it does make possible a concept of health other than in terms of “no disease”, Halliday then summarizes the ideas underlying the phrase “the cause of the illness”, as follows:
“(a) As regards the illness, the fields of observation and discourse are the features (signs and symptoms) of a mode of behaviour of an individual.
“(b) As regards the cause, the fields of observation and discourse are three” namely:
“(1) The field of the person. Under this heading are put the observations on the characteristics of the person before he became ill. These are innumerable, and may be noted in terms of any technique, for example, age, sex, weight, height bodily habitus, history of previous illness, history of illness in the family, blood pressure, menopause, intelligence, etc. The problem is to distinguish which of these characteristics may be regarded as relevant and causal.
“(2) The field of the environment. Under this heading are included observations on the factors of the environment which the person met at, or shortly before, the time he fell ill. The observation may be made in terms of any technique e.g., physical (trauma, heat, cold, light), chemical (diet, poisons), bacteriological, and psychological (death of a loved person, failure of promotion, etc.). Such factors are innumerable, and the problem again is to determine which of them may be regarded as relevant and causal.
“(3) The field of mechanism. Under this heading are put observations on the bits and pieces (structural, physical, chemical, psychological, etc.) which are set into action by the encounter and which ultimately bring about the particular mode of behaviour. The problem is to distinguish which of these are primarily involved.
And the three questions which he suggests one should attempt to answer about any illness are, of course, now quite well known: (1) What kind of a person was this before he took ill? that is, which characteristics of the person are relevant and causal? The field of the person. (2) Why did he become ill when he did? That is, which factors of environment are relevant and causal? The field of the environment. (3) Why did he become ill in the manner he did? that is, which part contacted the factor and which bits and pieces by preceding movement and ensuing movement finally made manifest the particular mode of behaviour? The field of the mechanism.
It seems at least, from this brief review of what is meant by cause or aetiology in medicine, that we can never strictly think in terms of a single or specific cause of a disease. On this ground alone it appears unsatisfactory to suggest that abnormal mental states can in themselves cause physical disease.
Body Mind Relationships, with Reference to the “Psychosomatic Hypothesis”.
It was assumed, and I think still is, that disease can arise in and affect the mind on the one hand, or can arise in and affect the body on the other; and we argue then whether disturbance in the mind may cause disease in the body. My excuse for venturing, with some trepidation and in however superficial and amateur a fashion, on a subject which has puzzled some of the best minds of every generation for well over two thousand years, must be that I believe it is impossible to practice or teach medicine without making some kind of assumption or taking for granted some kind of hypothesis about the relationship between what we call mind and what we call body.
Many people do not, of course, consciously make any such assumptions. They take them over ready-made from teachers and textbooks. I should put it rather perhaps, that our attitude to disease and our manner of dealing with patients must involve some hypothesis of body mind relationships, whether we are aware of it or not. Fortunately the problem I want to discuss is a fairly limited physical and psychological, in the sense that they arise in the body or arise in the mind, and have we any right to talk about events in the mind causing disease in the body?
Monism.
Victorian materialism regarded matter as real and objective and mind simply as some kind of a by-product of matter. Though, so far as can be seen from their medical writings, this is the view to which many medical scientists still adhere, others adopt some kind of psycho-physical parallelism or some form of monism, which regards mind or conscious states and brain states as different aspects of the same events.
