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Introduction
The relationship between biology and medicine is generally assumed to be a close one. They certainly appear to have much in common not least when it comes to human biology. The object of medicine – whether we take this to be human wellbeing or (as some would argue) human disease – is something that can be studied using biological techniques. There is, however, one subtle difference in focus. Medicine focuses primarily upon the individual – or how things are manifested in individuals. Epidemiology and public health notwithstanding, the aim of medicine is the treatment of individuals and the alleviation of individual suffering. Biology, on the other hand, is not focused upon the individual. While in the past we have tended to use type specimens to define whole species, biological data are now typically population based. Individual organisms are not of immediate concern to the biologist. Furthermore, when biologists look at populations, they may at times be concerned only with populations of particular traits or populations of individual genes.
In the clinical setting, one also finds humanitarian concern and a humanistic approach shown to those with whom one deals. The biological approach is scientific; it is objective and 'disinterested' – detached from its objects of interest. No room is allowed for value-judgements or emotions.
In recent times, there has been a move that would seem to deepen the relationship between medical and scientific thinking. That move has been towards ensuring that 'hard data' forms the basis for medical thinking. This can be seen in the emergence of evidence-based medicine. Evidence-based medicine aims to apply the best available evidence, obtained using the scientific method, to issues in the clinical sphere. Although the terms are sometimes used synonymously, evidence-based practice is distinct from evidence-based medicine – although it did emerge out of it. Evidence-based practice is typically associated with non-medical disciplines operating within the clinical sphere.
As the names imply, evidence – that is, research findings – form the basis upon which decisions are made and upon which professional practise is conducted. Implicit in this is the notion that there is a reasonable set of selection criteria determining which research findings are worth considering (and which are not) and how they should be best used.
A strict set of criteria about what constitutes evidence is adopted – at least should be in theory. This means that theoretical and qualitative studies are typically ignored or down-graded in favour of quantitative studies. Anecdotal evidence is certainly suspect. So too, it seems, are hunches and the insights born of years of professional experience. Here a lead is being taken from the scientific community where quantitative work has primacy. On one level, this is understandable. There seems to be something concrete about quantitative data whereas there is something more ethereal about qualitative reflection. One cannot devise testable hypotheses without first having something – that is, data or evidence – upon which to base those hypotheses. One cannot then test those ideas without having something tangible and measurable – that is, more data or evidence – that one can subject to objective statistical scrutiny. The tendency to think of data-based work as inherently superior to non-data-based work arises.
However, the data that constitutes evidence does not have a voice of its own. It must be scrutinised and interpreted. It also has a context and a background. It has a place but only within our prevailing worldview: within the context of the way in which we see things and how they are currently understood. When the statistical analyses are complete, interpretation is not. One must reflect upon the results, put them into context and interpret what the results signify. In short, there is a lot of qualitative activity that goes into quantitative research. Or, at least, there should be.
That there should be 'data pride' or even 'data envy' should seem odd. Collecting data is not necessarily the hardest of research activities. Indeed, this is something often delegated to more junior colleagues such as technicians or research assistants.
While data, once collected, cannot change, the way in which a body of data is interpreted is not immutable. Ideally, evidence should be subject to continual review. Interpretations are inherently provisional and must be allowed to change. In practice, this tends to occur most often as a result of the acquisition of new data. However, it is possible to completely reinterpret a body of evidence without new data being accumulated as occurs in a paradigm shift. That being the case, if one does allow inclusion of non-quantitative research, instead of being 'evidence-based' one may speak of 'research-based medicine' and 'research-based practice'. It is looking at evidence we already have from different perspectives that forms the basis of much of what I do and of what I wish to go on to consider here.
Survival
One of the key characteristics of how we lead our lives is that it is based upon a desire to stay alive: it is based upon survival and a survival instinct. While there are various animal and human examples of seemingly altruistic behaviour – even self-sacrifice – and while there are examples of those who want to end their suffering by ending their lives, what must concern us here is the typical human condition. It is one characterised by a desire for longevity combined with a tacit assumption that that longevity will have a sufficient quality of life. This is where I am stepping outside of the typical (scientific) biologist's way of thinking and looking in a different way. We study physical and behavioural characteristics of animals and humans in terms of how they are adapted to a survival role. We may talk, for example, of the 'survival value' of a behaviour. We sometimes talk of a 'survival instinct'. However, we do not talk about individual animal or human desires. That would be to sound too subjective and allow entry to the emotions. Furthermore, things such as these are not open to statistical analysis in the ways previously noted.
Significantly, biologists seem to have lost sight of the individual. It was not always so. One of the most famous phrases in biology is 'survival of the fittest'. I am sure that every day, this phrase is used by somebody somewhere. (Whether or not they use it in the correct sense is another matter.) Nowadays, this phrase has become inextricably linked with the notion of evolution by natural selection to such an extent that the two have become almost synonymous. However, although from his time, this is not a phrase coined by Charles Darwin (1809-1882), himself.
It was first used by Herbert Spencer (1820-1903) in his 'Principles of Biology' of 1864 and only appeared in 'The Origin of Species' from the fifth edition (some 10 years after the first edition was published).
Here, the survival Spencer had in mind was that of the individual. This is important to remember. Writing when he did, his was not the emphasis on populations or gene frequencies that has come to dominate modern evolutionary biology. Instead, the focus was very much on the life of the individual albeit with an eye on how this might eventually impact upon the species as a whole.
The phrase can also be somewhat misleading. The 'fittest' are not those who are necessarily the finest physical specimens in the sense used today in relation to athletes. Instead, the 'fittest' are those who are best suited to their environment: the habitat or conditions in which they live. One's ability to cope with such conditions has an important bearing upon one's ability to survive.
The 'fittest' are those who are 'not out of place' within their habitat. They are not under the influence of deleterious stresses from external sources. Those who are out of place and who do experience such stresses are those less likely to survive and those less likely to leave many, if any, offspring.
Daily Life - Factors affecting the survival of the individual
If we re-focus attention onto the notion of the individual in biology, we need to know what follows from this. We must ask what 'survival of the fittest' – and its corollary: the 'demise of the unfitted' – entails in everyday life.
I have a favourite story that I get from the French doctor turned philosopher Georges Canguilhem (1904-1995).
A man is going home one day but he meets his death on the way. Canguilhem suggests that the man might die in a car accident or be murdered. However, the way in which he meets his death does not matter only that it was sudden and unexpected. What matters in particular is what was found at autopsy. The man is found to have had a tumour in one of his kidneys. In time it would very likely have killed him, however, at the time of his death, he was completely unaware of its existence. This was a lesion that might well have shown up on examination except that there was no examination and no need for that man to request one because he experienced no untoward symptoms. The story was first presented in the early 1940s – although it became more widely known in the 1960s when the book in which it can be found – entitled 'On The Normal and The Pathological' – first appeared in English. In those days, there were few if any screening programmes or check-ups the like of which many enjoy today and the reason Canguilhem tells this story is to ask the question whether we should consider the man as having a disease or not. There is a lesion but no experience of associated symptoms. The story is primarily one belonging to the debate about the definitions of disease and health. However, leaving responses to that question aside, what this story highlights for me is the distinction that exists between the physical state of the body – which receives a significant degree of medical and biological attention – and what I shall call the experiential state of the individual: how one experiences one's own existence. While we get numerous signals from our bodies telling us, in effect, to rest, take it easy, avoid this or that food or activity, a complete map of the our physical state is not represented in our conscious experience of our bodies. That said, what we do have is a system that served our ancestors well – or well enough – in helping them survive. Hence, we are here today. At the same time, we should also recognise that there is a host of sub- or non-conscious signals also in play which no doubt contribute to this system.
The physician Marshall Marinker (1975) also confronted what is in essence Canguilhem's question although in a different way.
In addition to the symptom-less lesions Canguilhem described, Marinker comments upon lesion-less symptoms. He highlighted the problem faced by doctors when confronted with patients reporting symptoms for which no physical basis can be established. There are those who for nefarious reasons invent bouts of being unwell and so do not have any genuine underlying pathology. There are those who are genuinely unwell but without obvious physical cause. The dilemma for the clinician is how to differentiate between the two.
The reason I want to emphasise this distinction is because of the survival implications that ensue. The person who feels well is the person who is able to go about the day-to-day business of survival unhindered. The person who does not feel well is the person who is not able to go about daily life or, at least, is not able to do so, quite so well or successfully. In a biological context, a person who does not feel well is also one who is less likely to engage in what one might call 'reproductive activity'. Apart from the obvious mechanical aspects of reproduction, there is a range of activities associated with reproduction that require an individual's contribution – not least providing for and caring for infants. If there are numerous bouts of being unwell or if a single bout is particularly prolonged, an individual's reproductive capacity may be diminished and their ability to care for their offspring curtailed.
Taking this approach gives an individual's experience of themselves a much more prominent position in the life-as-lived scheme of things. It is certainly more prominent than standard biological approaches tend to emphasise. Traditionally, biological science has given little or no emphasis to the inner feelings or experiences of individuals. These are not things for which 'evidence' is forthcoming. Yet, experiences such as illness and the behavioural changes which may ensue can have a direct bearing on one's survival chances. No human being can claim to have felt perfectly well every day of their lives. Everybody has had a bout of illness of some sort at some point. What needs to be explored more fully is how one of the central tenets of biology – the survival upon which I am focussing – is affected. Going about the activities of daily life – eating, drinking, finding shelter, keeping clean etc – are important aspects of daily life because of the negative impact failure to perform these activities can have on the physical state of the body. Not feeling well enough to perform these tasks, can have a negative impact on individual survival.
Often certain types of experience – feelings of being unwell or in pain; feelings of not being 'quite right' – are what prompts us to see a doctor. Unfortunately, once a patient's symptoms have been described, the focus can become directed exclusively towards the patient's body. The patient may even begin to feel detached from their own treatment.
That there must be a physical body operating in an orderly way conducive to survival rather goes without saying. However, there are many different forms of body throughout the animal kingdom. Different organisms come not only in different colours, shapes and sizes but also in different body plans. What all share apart from being made of much the same stuff chemically, is a need for survival. Different physical and behavioural strategies may be adopted but all share the need to survive. This, even in the most lowly of creatures draws upon some form of self-reference or self-awareness – albeit at a rudimentary chemical level.
In order for there to be such a system of self-awareness, organisms must have an orderly configuration with the different parts operating in a coherent and integrated way. The particulars of this operation – how oxygen and nutrients are obtained and how wastes are removed etc – differ from species to species. Despite these differences, these physiological operations are also essentially about continuing the existence of the individual as a physical entity. An organism that is able to continue doing this we can consider as operating in an orderly or successful way. This may not perhaps be the way in which the body is usually described. Usually attention is given to the minutiae of physiological operation with little consideration for the whole. However, survival of the whole is what most physiology processes contribute to and bring about.
Fitting the environment
There is a third element to survival which harks back to Spencer's phrase 'survival of the fittest'. 'Fittest' here means best suited to a given habitat. Fitting or being adapted to an environment is a dynamic thing. More so than is sometimes appreciated. No individual survives without interacting with the environment within which they live. It is from the environment that the individual obtains all of its physical needs. It is within this environment that the activities of daily living – eating, drinking, sleeping, washing etc – are performed. These are behaviours directed at self-preservation and they include responses to aches and pain, feelings of being unwell etc.
Thus, the survival of the individual rests upon three inter-linked aspects of life. The physical state of the individual, their experiential state and the individual's ability to interact with the environment. Failure with regard to one or more of these can lead eventually to the individual's demise.
Using the notion of the survival of the individual as a basis for a revised bio(&)medical model
My emphasis on survival has been from what I described as a life-as-lived angle. It emerges from a primarily biological perspective. However, this three-pronged biological thinking can be used to inform clinical thinking. In so doing, it may even be possible to improve upon the prevailing biomedical model.
Two models which seek to describe the state of an individual emerge from the realisation that survival rests upon the three aspects of survival just listed. Other than calling one a two-dimensional model and the other a three-dimensional model, I have no other label for them at the present time.
A two-dimensional model
If we assume that all of an individual's externally derived needs are being met, the physical and experiential aspects of the individual can be depicted in terms of two orthogonal axes forming a partial boundary to a phase space.
The horizontal axis represents the overall physical state of the individual. This may be considered as the orderliness or success of the individual's combined set of physiological processes in ensuring its continued survival. The vertical axis represents the overall 'experiential' state of the individual. That is, the orderliness of the individual's combined set of self-referential experiences. (This is taken to include conscious and non-conscious internal forms of self-reference.) The horizontal and vertical axes, as imagined here, are such that as one moves along them there is an increase in physical disorder and experiential disturbance respectively the further one travels away from the origin. In this way, increasing levels of disorderliness within the individual are represented by these axes. In particular, the horizontal axis represents the degree of physical and physiological entropy that is present within the organism as a system. As one moves from left to right along the horizontal axis, the level of physiological disorder increases such that the physical processes associated with life become increasingly disordered.
A point is ultimately reached where physiological processes are no longer orderly enough to be conducive to survival. Similarly, as one moves up the vertical axis, the level of the individual's experiential disturbance increases such that the effectiveness of its contribution to survival diminishes accordingly. A point is ultimately reached where the individual's experiential state is not conducive to survival.
The intention here is to depict something of the overall state of the individual – in terms of physical disorder and experiential disturbance – as a point within the phase space. It is a description of the state of the individual that is being sought here. Points in the phase space represent, in effect, different levels of physical and experiential disorder within the organism as a system. Different points within the phase space represent different states of the individual.
What it is that is bringing about an individual's position within the phase space – especially those which bring about an increase in physiological or experiential disorder – may be due to a variety of things. It is a property of all things in the universe (even those which appear at first to violate the second law of thermodynamics) to experience an increase in entropy, so increases in physical and experiential disorder may be part of a natural process. However, this process may be exacerbated by the development of lesions or injuries or psychological upset.
It should be noted that the point representing an individual's state is not static. The position that an individual occupies within the phase space varies as their physical and experiential states change.
This point should not be considered to be precisely measurable in a scientific sense. It is not meant to be a model where specific values are entered onto or read off of either axis. Rather it is meant to provide a notional way of looking at and depicting the human organism as something actively trying to survive. As such, the model is meant to act as a visual heuristic; a way of mentally representing and understanding the state of an individual.
Importantly, this model provides a way of depicting and thinking about the individual as a system which has both physical and experiential properties. Of course, neither exist in complete isolation from the other. Even in the lowest animal forms, were 'experience' may not be an entirely accurate term to use due to the absence of an elaborate nervous system, there is still a flow of self-referential information of sorts be this chemical or perhaps electrical. Rudimentary animal forms may still be integrated systems because of the communication that goes on within the organism.
The phase space between the axes represents all of the physical and experiential states conducive to life. Beyond the axes there are no states conducive to life.
A three-dimensional model
As already noted, no individual lives in complete isolation. In order to survive, each individual must interact with the world in various ways so as to obtain their daily needs. One's ability to interact with one's habitat can also be accommodated by this model by adding a third axis. This axis represents the ability of an individual to perform activities conducive to individual survival. In keeping with the approach adopted for the first two axes, the further one moves away from the origin, the greater the constraint on activities conducive to survival becomes. In effect, this is an axis which describes the extent to which an individual's ability to perform the activities of daily life conducive to survival, is constrained.
An individual may be unable to obtain from an otherwise abundant environment their needs due to injury or paralysis. Such individuals may have to rely upon the assistance of others to perform certain tasks on their behalf.
Sometimes the environment may be lacking those things that are essential for the individual survival. This is typically what occurs in times of famine and drought. Under such conditions a different kind of assistance in the form of relief aide may be required. In both cases, without the assistance of others, the individual's survival chances are compromised.
In Practice
In order to describe the practical application of these models, first consider the two-dimensional phase space. An individual who feels well, who is not conscious of any adverse feelings and whose physical processes are operating in an orderly way is somebody who rates low on these two axes.
They would be represented somewhere to the lower left of the phase space within the area [a]. We might, if we were to stray into the debate about the definition of health, begin thinking about this area as where states of 'health' might be situated. Conversely, an individual who feels unwell and whose physical processes are not operating in an orderly way is somebody who rates high on both axes. They would be represented somewhere to the upper right of the phase space within the area [b]. Exactly where one might choose to place a particular individual is a matter for judgement rather than mere physiological or psychological measurement. As I said, the intention is for this model to act as a heuristic and provide an appreciation of the overall state of the individual rather than a precise measurement.
As noted earlier, not all cases presenting to the clinician can be accommodated by the prevailing medical model which adopts a primarily linear approach. There are cases where an individual may feel well yet have a lesion of some sort and there are others where an individual may feel unwell but have no obvious physical basis to which this can be attributed. (As in the Canguilhem and Marinker examples mentioned earlier.) Position [c] to the lower right of the phase space represents the situation where an individual feels well but has a lesion of some sort. Here, there is no feeling of being unwell but there is a degree of physical disorderliness. Position [d] to the upper left of the phase space represents the situation where an individual feels unwell but whose physiological processes are operating in an orderly way. Here, there is a feeling of being unwell without obvious physical cause. While these scenarios cannot be fitted into the prevailing biomedical model, they can be represented by this two dimensional model relatively easily.
Furthermore, this model also allows phenomena such as the placebo and nocebo effects to be represented. When somebody takes a dummy pill or undergoes a sham operation, they may feel better (the placebo effect) or worse (the nocebo effect) afterwards. This may be represented by a vertical shift from the subject's previous position in the phase space; down in the case of the placebo effect, up in the case of the nocebo effect. These are effects that again the biomedical model cannot accommodate and often quietly overlooks. Note that explanations for these and other effects are not being offered here but hopefully scientifically acceptable forms of state description are.
Disability and Inability
The question of disability has also been problematic for the biomedical model. Based on this model, it is sometimes hard for clinicians to afford disabled people the status of being fully healthy. At the same time, neither do they fit neatly into a category equivalent to 'diseased' or 'unwell'. The use of the three-dimensional phase space model allows this impasse to be resolved. Separating out the idea of the ability to behave in ways conducive to individual survival from the dimensions depicted on the first two axes removes this dilemma.
The third axis represents the degree of constraint there is upon the individual when it comes to interacting with the world and obtaining their daily needs. With the third axis added, the descriptions associated with the four scenarios considered earlier remain but now an appreciation of an individual’s ability to go about their daily interactions with the world can be included. In addition to the previous scenarios, positions [a]-[d] now represent no restrictions or constraints on this ability. Positions [a']-[d'] can now be added.
These represent states as before but now where the individual's ability to interact with the world and go about daily activities conducive to survival is severely curtailed.
Consider, for example, a person who is quadriplegic. Such a person can be physically and experientially located at position [a], were just the first two axes used. However, they are seriously constrained when it comes to ensuring that their daily survival needs are met should they be left to fend entirely for themselves and would be represented at [a'].
However, if that person is provided with support and obtains their needs regardless of their disability, their state is equivalent to [a] (above). This model does not prescribe how daily needs should be obtained or by whom the associated activities should be performed. Disabilities are essentially hindrances in one's ability to interact with the wider world in going about one's survival needs. These hindrances may be overcome with the help of others. Thus a severely disabled person can still be described as 'healthy'. This distinction is not possible with the prevailing medical model. Using this model, it is possible to envisage scenarios in which a so-called 'disabled person' may be just as successful at ensuring their daily survival as a so-called 'able-bodied' person, albeit with the help of various aids or with the assistance of human or animal helpers.
Putting the Patient in the Picture
In a practical context, a clinician might use these models to help gain a mental impression of a patient's condition. Seeing a patient's overall state in two or three dimensional terms rather than the usual one may help enrich their understanding of a particular clinical case. They may also perhaps use one or other of these models to help a patient understand their own condition. Avoiding technical terms and using just a simple sketch it should be possible to convey to the patient an idea of their overall condition. This may be particularly helpful when trying to convey how it can be that a patient might feel fine yet have a serious lesion of which they were previously unaware or how they might feel unwell but have no discernible cause. In the former scenario, the patient would be represented in area [c] to the lower-right of the phase space; in the latter they would appear in the upper-left, in area [d].
Previously, with 'health' and 'disease' at opposite ends of a linear axis, accommodating these scenarios was impossible. Consequently, patients could not be offered satisfactory explanations or descriptions of their condition in such terms.
This was not only been problematic for clinicians but left patients confused and unsure of their situation. Some may even have left the consulting room frustrated and disenchanted with their doctor or with the whole medical profession. Having a model that acknowledges the existence of symptom-less lesions and lesion-less symptoms ready, can help the doctor and patient alike. It provides in advance a recognition that while not everything can be easily explained at least it can be depicted and the doctor is knowledgeable enough to be able to do this. Having a model that can be drawn for the patient, which they can even take away with them, may offer a better alternative. Ideally, a patient should leave a consultation assured that their doctor is aware of all the potential scenarios that might describe their particular condition.
The biomedical model is enticing – especially to the evidence-based and scientifically minded. However, evidence is often treated in a one dimensional, linear way and viewed in terms of normal distributions.
This leads to various assumptions which tend to be based more on the mathematics underpinning the model than upon the individuals concerned. It is the individual patient to whom models should be fitted and not vice versa.
Conclusion
Taking a lead from Shakespeare allow me to conclude by saying that I have certainly not come to praise the biomedical model – but neither have I come to bury it. It seems pointless to try. Why try to throw out something that is so entrenched. Others have tried to no avail. Perhaps we should not attempt to inter the biomedical model lest good be interred with it. However, I do wish to modify it.
For some reason, the biomedical model seems to be something towards which many tend to gravitate. That being the case, why stop them?
Let them gravitate in that direction but at the same time when they get there, let them find more than they might be expecting and furthermore that there is scope for development.
My horizontal axis representing the physical state of the body, is in keeping with the physiological evidence that is so often collected. However, I suggest that it cannot be used on its own if we are to describe the individual properly.
These models, based upon the notion of survival, attempt to represent the individual as an integrated system in active, living terms. Based upon a fundamental tenet of evolutionary theory, they are general biological models. However, they serve as reasonable bases for improved bio-medical models because individual survival is not only something that medical care seeks to ensure, it may be considered to lie at the very heart medicine itself. That being the case, these models should have medical as well as biological relevance and be able to serve an integrative role in relation to the two disciplines.
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