Biomedical Concepts and the Concept of Biological State

In what follows, I should like to report an unended – perhaps unendable – struggle. I say struggle because I am still wrestling with how best to present certain ideas. So this is very much what we call a 'work-in-progress'.

I have been trying to find a more precise biological usage for certain biomedical terms. In this, my interest has focused primarily on somatic – that is, physical – conditions. At the same time, in order to do this, I have found that I have needed to approach the human body in a way that is different to that typically found in standard textbooks on the subject.

Thus, I have two separate things I want to do today. After a brief detour to help set the scene, I shall consider a way of modelling animal organisms, in particular human beings, from a fundamentally biological perspective and then I shall review a number of biomedical terms in light of this model.

Before I start, I should perhaps point out that in my title, the phrase 'biomedical concepts' refers to various words and associated ideas that are commonly used by the medical and allied professions. These are words which one finds biologists having to use because the objects of medicine are increasingly becoming the focus of biological interest. Some of the biomedical terms I shall be considering can be found in ordinary language and have ordinary, everyday meanings. However, these meanings are not good enough for use in a scientific context where precision is important. These words are in need of clear technical definitions if they are to be used in a scientific way. Those concepts I have in mind include illness, disease and health – but there will be others I shall consider later – as well as some I will not.

I have also used the phrase 'biological state' in my title. 'Biological state' is not a standard expression that one finds used by biologists. I have had to adopt this term because there is no other that refers to what I hope to describe. 'Biological state', as I envisage it, refers to the state of an organism as a single, whole system and does not refer simply to the sum of its parts. To be absolutely clear at the outset, biological state is not the same as homeostasis.

However, there are some background ideas I should like to address first by way of the detour to which I referred a moment ago.

Theories of Meaning

Because I am considering the technical definitions of a selection of biomedical terms, I would like to start with a couple of points about meaning which will give some idea of the approach I am adopting.

There are various theories of meaning but these can be divided into two basic divisions. There are what are referred to as de facto theories and de jure theories.

De facto theories consider the meaning of a word in terms of how it is used. Wittgenstein, for example, said that 'the meaning of a word is its use'. That there are de facto theories at all highlights the fact that words and their meanings can change over time and that there can even be regional differences in the way a word is used.

De jure theories consider the meaning of a word in terms of how it ought to be used or in terms of the rules for its use. What is more, de jure theories sometimes claim that the way in which a word is being used is incorrect. Thus, de jure theories point to the control we can have over words.

In science, it is not uncommon to have this control. New words are coined from time to time. On those occasions, scientists are in a position to state how they intend these words to be used. Thereafter, the meaning may, of course, go on to evolve into something else. Occasionally in science, the meanings of old, seemingly established words need revision. Here what we might call a de jure approach to definition revision can be adopted and tidier meanings can be prescribed.

Consider, for example, the word sick. How is it used and should it be used? In American English, sick is associated with being too unwell to work; of adopting what Talcott Parsons called 'the sick role'. Being sick has an official social status which allows one to continue to be paid while unable to work and to claim certain benefits if eligible. However, in British English, while sick can have much the same connotation, it is also strongly associated with nausea and vomiting. Often somebody about to vomit says that they feel sick or feel that they are about to be sick. Similarly, those who have just vomited may say that they have just been sick. Sometimes the stuff that has been vomited may even be referred to as sick. The chances are that, as I speak, somewhere in Britain, somebody, in a doctor-patient or patient-nurse context, will be using the word sick in just this way.

But how should a biological scientist – irrespective of whether they are British or American – use the word sick? This is a genuine problem; not simply a linguistic puzzle. As I said earlier, increasingly, as biologists, we are concerned with biomedical concepts and notions in our teaching and even in our research. Therefore, we need a precise vocabulary to avoid ambiguity and confusion. When the British use sick in relation to nausea and vomiting and the Americans use sick to mean (quite literally) 'socially-sanctioned-to-be-off-work', then there is potential for confusion. Whether this confusion is a particularly serious one that would go unrecognized for long is another matter. However, it serves to illustrate the point I wish to make – a point which, by extension, may apply to and be much more problematic in relation to other words.

Taking a de jure style approach, I would advocate that biologists adopt the American meaning of sick since we already have the words nausea and vomiting to convey their meanings quite clearly. Here, there is much less scope for confusion; the words are more precise – they are, literally, more scientific.

Thus, what this illustration shows, I hope, is that I am seeking to formulate scientific definitions (and understandings) of those biomedical terms for which there is currently, I believe, a certain lack of scientific clarity – and, because I operate in a scientific context, because it is scientific understandings I seek, I am adopting something of a de jure style approach.

Theories of the Organism

In seeking a more precise meaning for terms, such as illness, disease, health etc, we often, I think, underplay the fact that what these terms all have in common is that they all apply, in various ways, to the human body. So there are two options open to us. We can take what might be called a direct approach and try to address each word in turn given what we already think we know, or we can take an indirect approach and address each word after having first considered the object to which these words apply – that is, the human body – and ask what it is about that body that evokes the need for these words. It is this second approach that I shall be following here.

Historically, one finds that some of the words we currently use originate from a time long before modern scientific investigation into the human body began. Whether our use of these words has kept pace with the increase in our knowledge, is an open question. However, even though our knowledge in this area has increased considerably during the last couple of centuries, we are yet to develop a theory of the human body as a single entity, that is, as a single organismal system. The reductionist approach that we have adopted has meant that the vast bulk of our knowledge about the body can, at best, be described as fractionated. Thus, words that have a holistic connotation – in that they refer to whole body states or experiences – have an inherently uncertain basis in science. The words illness, disease and health are like this.

The current approach to teaching anatomy and physiology can be summarized in these diagrams which represent just a few of those one typically finds. Indeed, in the hospital library here I have found this approach adopted by a number of different books, not only those in English but also a number in Swedish.

We see the body divided up into a series of levels of organization. With only minor differences, virtually all such illustrations are much the same. This approach can have its benefits. I have been able to use it to explore, with students, a number of interesting questions. So I do not reject this approach entirely out of hand as it can prove to be a useful tool. However, typically, textbooks of anatomy and physiology describe the body system by system without ever concluding with anything that resembles an integration of those systems into an organism as a single entity. Indeed, arguably, what textbooks refer to as systems are, in fact, really only sub-systems. It should be the organism which is viewed as the system per se.

Thus, the situation is rather like that in our nursery rhyme where:

Some of our biological techniques are exactly like this. We deliberately break things open to see what is inside but having looked inside, we don't seem to be able to put things back together again conceptually.

What I believe is needed – certainly what I am drawn to – is a type of general systems theory of the organism, perhaps in keeping with the kind of general systems approach proposed by Ludwig von Bertalanffy (1901-1972) where we can think of whole system states (or biological states) rather than numerous individual, physiological parameters viewed separately.

Here, an example may be helpful:

Consider a person who takes a drug. The physiological behaviour of that person may change as a result. If so, the usual interpretation is in terms of what effects the drug had on the person; the two are viewed quite separately. This is not necessarily wrong; it can certainly be a useful model and there may be good reasons for adopting this methodological approach. However, this is not the only perspective we might adopt.

In a systems approach, one can think of an organism as a single, complex system into which something – here, a chemical which we happen to call a drug – is introduced. As a system, which is materially a series of chemically-based structures and processes, the organism is now different; it is quite literally a chemically different system. The state and outworking of that now newly-configured system, in physiological terms, is a product of that new configuration. Indeed, this is generally the case: within a given context, the state of a biological system, in physiological terms, is a product of how it is configured internally.

From this perspective, it is not so much the drug that is causing a change. Rather, it is the system which is exhibiting a state in keeping with the way in which it happens to be currently configured. Had different chemicals, for example, the one we call water, been introduced, the system would have had another configuration and would have behaved according – it may have changed from a state which registered itself as 'thirsty' to one which registered itself as 'not-thirsty'.

The change from 'thirsty' to 'not-thirsty' demonstrates how the body is also a self-monitoring system. There is a huge range of neural and chemically-based reflexes and feedback mechanisms that monitor the physical state of the body. Most of these operate below the level of consciousness. However, there are some that do reach our attention and, in so doing, prompt certain behavioural responses. I have just referred to one in passing. In response to an experience of thirst, one adopts some form of response associated with obtaining water. This demonstrates an important point. The organism, as a system, monitors itself and responses to itself in such a way that it tries to ensure its own continued survival.

While a great deal of biomedical attention has focused upon the material nature of the body, the description of the body that has emerged is a rather limited one. The body is not just a material object consisting of structures and processes that stay alive; it is quite literally more animate than this. The body is a system that survives in the world. It persists because, as a system, it monitors itself and prompts responses and reactions that contribute to its survival.

A Two Dimensional Model of Biological State

It would be helpful if we were able to represent these ideas visually via some form of model. So let me try. Let us use two standard axes representing what, for the time being, I shall call: the 'physical state' (horizontal axis) and the 'monitored state' (vertical axis) of the organism.

Physical State

As regards 'physical state', we need to think of the organism as a single, physical entity – not the sum of a set of sub-systems or other parts. As I have already noted, we do not have a theory of the organism as a single entity as such. However, there is some thinking upon which one can draw. Something we commonly overlook as biologists is how biological organisms disobey at least one of the laws of physics. In particular, organisms display what the physicist, Erwin Schrödinger (1887-1961), described in his book What is Life? (1944) as 'negative entropy' (sometimes called 'negentropy'). That is, organisms in maintaining their various configurations as systems, run contrary to the second law of thermodynamics and so display what can be described as organismal 'negative entropy'.

Entropy can be understood as a measure of the order or, more accurately, the disorder within a system – the greater the degree of entropy, the greater the degree of disorder. Physically, organisms persist by maintaining a certain degree of orderliness in structure and operation.

Schrödinger's term 'negative entropy' was, by his own admission, a somewhat awkward expression. It also attracted some opposition from his colleagues. However, I believe that it serves as an interesting idea and point from which to work. We may not be able to measure this organismal order, or disorder, in the usual way but it is still a potentially viable notion. It suggests that we might think of changes in the body’s structures and processes in terms of how they contribute to organismal entropy, that is, how they contribute to the body's systemic level of order or disorder. Therefore, I suggest representing this 'organismal entropy' in the physical configuration of the body, on the horizontal axis.

Monitored State

In a biological system, 'monitored state' includes one's conscious experience of one's own body and a host of reactions and reflexes below the level of consciousness. Referring back to the example of thirst, when the 'physical state' of the body lacks water, there is a certain loss of order in the system as a result. This is first monitored at a non-conscious level. Eventually, this may reach consciousness as an experience of thirst which compels the individual to seek out something to drink.

So, this axis of 'monitored state' is in a sense the axis of 'how-one-feels'. However, this can manifest itself in a variety of different ways. Sometimes we might interpret this as a feeling of well-being, a feeling of hunger, thirst, being hot or cold, also having different feelings and intensities of illness. Thus, this single axis refers to something very complex. However, although it may seem ambitious to group all these together like this, I feel justified in taking this approach because this axis can be thought of as representing literally how one would describe oneself if asked the question, 'How are you?' As a result, it represents what the individual’s immediate needs are taken as being. This, in turn, informs how they must go about their immediate survival activities in terms of whether they must eat, drink etc. So, as well as being an axis of how one feels, there is a real sense in which this is an axis that depicts survival needs as well.

However, instead of calling this axis 'how-one-feels' or 'survival needs', I am currently favouring the term 'Experiential Disturbance'. I get to this idea in a rather roundabout way starting with a reference Georges Canguilhem (1904-1995) makes to the work of René Leriche (1870-1955). Leriche suggested that 'health is life lived in the silence of the organs'. I do not entirely agree with this. When one's organs are silent, I would see this as one merely feeling fine. However, the notion of the silence or otherwise of the organs is a useful one from which to work. Feeling hungry, thirsty, too hot, too cold and having different experiences of illness can be considered as 'bodily noise', 'disquiet' or, as I prefer, 'disturbance'. It is in response to such 'experiential disturbances' that the physical state of the body can be modified when need arises. For example, when water levels in the body become depleted, we respond to an 'experiential disturbance' we have come to label as 'thirst'. 'Thirst' is only a surrogate. By responding to the surrogate, we ensure rehydration indirectly. Similarly, 'hunger' is only a surrogate that ensures the provision of the bodily chemicals we call nutrients which are contained in what we call food.

As 'experiential disturbance' increases, our need to respond to and reduce or nullify that disturbance also increases. Our responses may become more and more urgent. However, it should be pointed out that an adequate response may not always be possible. 'Experiential disturbance' may increase unresolved to a point where consciousness may be lost and, as a result, the individual may perish.

Where the two axes meet, there is zero 'Organismal Entropy' (that is, complete 'organismal order') and zero 'Experential Disturbance' (that is, the organs are totally silent). So where the two axes meet, we begin with a deliberately idealized state. This may be a totally unrealizable situation but such a point serves as a useful reference or anchor point. As one moves along each axis, the things represented there become progressively less ideal.

As one moves to the right along the horizontal axis, the 'physical state' of the organism becomes increasingly disordered – there is, greater organismal entropy. Ultimately, a level of disorder incompatible with life will be reached. (Note here that, it is not when there is complete disorder that death occurs; instead this occurs when a level of 'organismal entropy incompatible with life' is reached.)

As one moves up the vertical axis, the organism's level of 'experiential disturbance' increases as described a moment ago.

There are, however, limits. We cannot go beyond the idealized limits depicted where the axes meet and we cannot go outside the physical and experiential limits that are viable with life.

Examples

It may help to give some examples to illustrate how this model works. So let me use a favourite story. Georges Canguilhem gives the example of a man who dies in a car accident or who is murdered and who, on autopsy, is found to have had, unbeknown to that man when he was alive, a cancerous tumour in one of his kidneys. How does this model relate to that man?

This man's physical state was compromised by the presence of the tumour and there would have been a certain level of systemic disorder associated with the presence of that tumour. We can perhaps think of his physical state, therefore, in terms of a range which varied according to the different daily circumstances the man encountered.

For some reason, this man's body seems to have generated little experiential disturbance – at least in relation to the tumour. (Although, that is not to say that there was none occurring below the level of consciousness.) However, what 'experiential disturbance' the man did have as part of his ordinary daily life can be represented as a range on the vertical axis.

Thus, the man's position on this model is represented in the following area:

Had there been experiential disturbance – perhaps a feeling describable as illness – as a result of the tumour, then he could have been represented as follows:

Had he been feeling ill but had no tumour or any other overt physical cause for that illness, then he could have been represented as follows:

Had the man been feeling well and had no tumour or any other overt physical disorderliness, then he could have been represented as follows:

The idea is that we try to plot the physical state of an individual's body (in terms of 'disorder') and the experiential state of their body (in terms of 'disturbance') within the same space.

To be clear, individuals can move around this space. Also, whether or not we can fill every corner of the space with an example doesn’t really matter; the idea is to see how different conditions might be plotted and try to see how this helps our thinking.

What this model is and is not

It is important to remember that, as presented, this model applies only to individuals. It is not population-based, it has not been derived from statistical data and it is not meant to represent groups.

Also, it is based upon ideas about how bodies work as wholes within an evolutionary context.

As I have already noted, what this model is trying to do is provide a way of depicting the organism in more than just physical terms. The organism which survives in the world is not just a physical thing but a system that is aware of itself in various ways and to various degrees. This, in turn, contributes to how it goes about ensuring its survival, so this should be given due consideration.

So, how might different biomedical concepts be viewed in light of this model?

Relating Biomedical Concepts to the Concept of Biological State

I would now like to focus on the following biomedical terms:

Well-being

Illness

Lesion

Pathological

Disease

Injury

Health

These have been chosen simply because they are commonly used in medicine and increasingly so in biology.

Well-being / Illness

The notions of well-being and illness are facets of the vertical axis; they correspond to different aspects of 'experiential disturbance'. Well-being is associated with less 'experiential disturbance' than illness. As such, well-being and illness are entirely subjective experiences and cannot be measured in an objective way. As a result, it is the individual who decides how to describe his or herself. In this individual-based approach, it is the individual who determines the level at which 'experiential disturbance' becomes worthy of comment or outright complaint and the level at which it goes unnoticed.

Much depends upon the person involved. One individual may consider himself well despite being aware of a certain level of experiential disturbance. Another person with theoretically the same level of disturbance may find this state of affairs quite unacceptable. Furthermore, some may choose to stoically, or doggedly, deny considerable experiential disturbance even when it is quite obvious to them. However, biologically the consequences are fairly straight-forward.

The individual who is least disturbed within themself is the one that is more likely to have the opportunities to be able to fulfil the biological imperatives associated with survival and reproduction most successfully. Others, for whom their level of experiential disturbance is a distraction, will be impaired in this respect.

Lesions

I would like to suggest that lesions be understood as physical configurations which increase organismal entropy in some way. That is, lesions increase a body's physical disorder and so run contrary to organismal survival. Lesions are usually considered as localised, anatomically discernible things. However, what characterizes a lesion, I believe, is not its being anatomically atypical or unusual – there are many such structures like this that are of no consequence – rather, it is how the lesion contributes to organismal disorder that is important; they are sources of increased organismal entropy. However, it should be noted, that this can occur with or without an increase in experiential disturbance.

When there is an increase in experiential disturbance – so that the individual considers him or herself to be ill as a result of the lesion – we have the opportunity of specifically referring to such a lesion as a 'pathological lesion'. This approach would help make the use of the word 'pathological' more precise and more in keeping with its etymological roots – coming from the Greek word pathos whose meanings include suffering.

Where there is a lesion but no experiential disturbance, such lesions can be considered 'non-pathological' in that they do not or are not currently causing overt illness. Some, perhaps all, lesions that go on to become 'pathological lesions' begin in this way as 'non-pathological lesions'. The distinction I am making here is based entirely upon whether or not they are currently associated with an experiential disturbance that the individual labels as illness.

A lesion which is currently 'non-pathological' can also be 'pre-pathological' in that it may be of a type which, if left alone, may go on to cause illness. Also, a 'pre-pathological lesion', if discovered on routine screening and dealt with accordingly, may be prevented from causing further organismal disorder and be prevented from leading to overt illness. In this case, it will have been prevented from becoming a 'pathological lesion'.

Before moving on to disease per se, I should note that just as not all lesions give rise to experiential disturbance, not all experiential disturbances are the result of lesions. Some experiential disturbances may be the result of more disseminated organismal changes that give rise to an increase in organismal disorder. Similarly, an infection may produce its effects in a disseminated way.

Disease

Let us now consider disease. Quite literally, the word 'disease' means 'a loss (or lack) of ease', a meaning which the word illness has now largely come to convey. Today, the word 'disease' seems to have come to imply that something more tangible than just a loss (or lack) of ease is involved. I would like to suggest that in order to call something a disease there must be two things involved: something (which may be localized or disseminated) which increases organismal disorder and an associated experiential disturbance that can be described as illness.

To be clear, physical lesions and infective agents are not disease per se – just as illness is not disease per se. Rather, for a particular state to merit the label 'disease', I am suggesting that there must be a means whereby organismal disorder is increased and there must be an associated experiential disturbance at the same time. The reason why I want to put it this way is that one frequently finds people referring to lesions and diseases as if they were the same. Hence, why I also wanted to distinguish between pathological, non-pathological and pre-pathological lesions.

A disease state situates the individual towards the upper-right of the model space.

However, this is not to say that everything that can be said to belong in the upper-right of this diagram should be called 'disease'. If one is injured, this may increase organismal entropy and cause an experiential disturbance yet one might not choose to call this a disease but an injury instead. Biologically, disease and injury may have similar consequences for the individual; both may be equally debilitating, even life-threatening. However, medically they may be labelled differently because the cause or circumstances associated with how that state came about may be taken into consideration.

Health

I have deliberately left consideration of health until last. It is not enough to simply say that it belongs to the lower-left of the model just because disease is associated with the upper-right. This assumes that health and disease are opposites, or counterparts, in some way. So far as I can see, this relationship has not been established, even though there are those who talk in this way.

Neither is it enough to simply say that health belongs to the lower-left of the model because that is where the ideals of complete order and organic silence are situated.

Instead, we need to find a place for health in its own right.

From a purely biological perspective, so long as an organism is experientially undisturbed enough to be able to survive and engage in reproductive acts, that is all that seems to matter. These are the biological imperatives that organisms such as ourselves are geared to perform. Even when there are internal lesions, as long as they do not impede the performance of these biological imperatives, they will have no biological impact. From this perspective we might consider health to be merely equivalent to that level of experiential disturbance one can tolerate without the biological imperatives being disrupted.

This may be the biological reality as it pertains to animals in the wild. So long as they are 'undisturbed enough' to perform the biological imperatives they are 'healthy enough'.

But this is hardly likely to be an acceptable state of affairs for humans. A purely biological perspective is not necessarily a humane one – or one acceptable from a humanistic perspective. Given the results of some routine screening that shows somebody to have a pre-pathological lesion which, if left untreated, is likely to cause considerable suffering and perhaps even loss of life, a clinician cannot suggest to his or her patient that there will be no treatment at this stage because that patient is still able to perform their biological imperatives unhindered. What is sufficient for a life to be lived out successfully from a purely biological (or 'wild-type') perspective may be quite unacceptable from a humanistic medical perspective.

Medically, a more specific, perhaps more limited, notion of health may be necessary. The nature of this limitation may be a direct product of the tools available to the clinician and may change as new tools become available. Increasingly, clinicians are able to spot lesions during their 'pre-pathological' phase and act before they have a major effect on systemic entropy or cause experiential disturbance. From this perspective, we might consider health to be more than merely equivalent to being 'undisturbed enough' to get on with living, in which case, it may involve some desirable degree of organismal orderliness as well. What that degree of orderliness is, or should be, may be for us to decide.

There appear to be (potentially, at least) different versions of health when viewed from biological and medical perspectives. In fact, it is worth asking whether biological and medical perspectives on health need to come to the same conclusions. The answer may well be: no. Indeed, if there are different versions of health from these different perspectives, this may not be as problematic as one might assume. It may even be a good thing that we can make such a distinction.

Our modern day personal aspirations are somewhat idealistic. We crave a lasting sense of well-being and attractive, lesion-free bodies. This is not what Nature seems to be able to provide – at least, not on its own. To do this, Nature seems to need help from the medical and allied professions. So maybe we can let biology consider health and the other biomedical concepts in more fundamental, naturalistic terms and let human aspiration exceed what Nature has to offer via the invention and application of new medical technologies – within, of course, the appropriate ethical framework.

Conclusion

And so I conclude this report of my unended – perhaps unendable – struggle but not, of course, the struggle itself. As I said at the beginning, this is very much a 'work-in-progress' and I suspect it always will be. In that respect, may I thank all those of you who have, in your various ways, contributed to this work while I have been here. I have had many stimulating and informative discussions that have added to my ideas. Sometimes what you may have considered an inconsequential or chance comment has meant something more significant to me. However – for his intellectual generosity – I must, of course, give special thanks to Lennart Nordenfelt.

Acknowledgements:

I would like to thank the trustees and fellows of the Konraad Lorenze Institute, Altenberg, Austria, where, as a Visiting Fellow, I was able to develop the ideas expressed here. I would also like to thank Annette Lewis for her help in the preparation of this transcript.