Medicine: Right Idea, wrong science? Should critical realism be the new science of medical practice?

Alistair Appleby is a GP for the Highland Health Board and Hon Senior Clinical Lecturer at the University of Aberdeen. He is on X: @DrAlAppleby

A patient in pain – trust the scans, or the patient’s story?

It is generally agreed that the practice of medicine is a good idea: But is it based on the wrong science?

Imagine for a minute a patient with chronic pain. An orthodox scientific approach would arrange blood tests and scans, nerve studies and x–rays, scopes and biopsies. We would prescribe evidence-based therapies devised in objective studies such as double-blind trials. We might reassure the patient that we “…can find nothing wrong” if these were negative.

However, this account alone is insufficient and now rightly attracts criticism.¹

Or we could take a detailed history of pain, what does it feel like? Enquire what was happening emotionally at the time it all started? We could enlist the help of psychologists and counsellors and acknowledge that only the patient can truly describe their own distress or perceive the nature of their disorder.

This account too, in isolation, is dangerous and limited.²

“The clinician is expected to approach the patient in a way that is not only scientifically valid and evidence based, but also sensitive to the full range of human capacities, including individual experience, needs and values. These two aspects are typically expected to coexist or merge in the concept of knowledge‐based practice , but exactly how such a merger should come about is far from obvious”.³

As general practitioners, we know that these two accounts are both meaningful and necessary; but each is incomplete without the other account. Recent debates have highlighted that simplified versions of science can seriously undermine our work. Medicine which overemphasises patients perceptions can do likewise.² This illuminates the potential damaging effects which the lack of an explicit philosophical framework may be having on medical science.⁴ As Stempsey argues “…a philosophical stance is required even to define a problem as a medical problem”.⁵ It seems that medicine is adrift between these two polarised views, resting on a weak foundation, even perhaps the wrong view of science.

If our two contrasting pain accounts rest on truth, but cannot be reconciled without appealing to the other, this implies that a third, more fundamental and encompassing account is likely to be more correct.⁶ To acknowledge this fully we need to do no less than re-think our version of reality. However, I suggest that these changes will feel intuitive and familiar to GPs. I suggest this would be best based on a framework of ‘Realism’ in general and ‘Critical realism’ specifically.

What is a ‘Realist‘ view ? – introducing Critical Realism

Engel, in seeking to create the biopsychosocial model, used early systems and complexity theories to provide frameworks for his ideas. However, Engel’s multifactorial idea did not stand on a particular philosophical framework or call for reform of medicines over simplified science.⁷ This arguably left the biopsychosocial model floating on a sea of philosophical uncertainty.

I want to further the argument that a form of “realism”, specifically Critical Realism (CR) is currently the best, and perhaps the only plausible framework for the human sciences as applied to Primary Care. CR is already commonly used and recommended in medical research,⁸ and more widely in other sciences from biology to cosmology. Here, resting on the work of Roy Bhaskar, I describe some of the basic building blocks of “Critical Realism”^6,9

Concept 1 – There really is something that is real. Imagine a world before man existed. It seems plain that the general facts of cosmology, the existence of gravity, of matter and the physical properties of the universe already existed. Biological growth and organisation were present, complex relationships existed between organisms which included movement, symbiosis and basic forms of communication. Critical realists believe that science is a process of discovery of an order which pre-dates and is not dependent on humans. The matter, forces and fields, structures and organisation of this reality is independently “there to be discovered”, not just experienced or imagined. We believe that the patients blood tests and biopsies represent an important part of reality which does not rest on individual experience or perception.

In philosophical terms this is called a “realist ontology” and GPs will have no trouble with this concept: it is foundational to the basic sciences and is, according to CR, largely correct.

Concept 2 – Stratification.  CR proposes, and this is substantially accepted in other branches of science, that reality is stratified, rather like a cheesecake. These layers, increasingly complex as we move ‘up,’ may bleed into each other somewhat but differ in their characteristics. This is usually represented something like this.

Diagram 1 – stratification of reality according to complexity

In the basic layers, the natural forms (e.g. atoms) and forces (e.g.electromagnetism) relate to each other in ways which are somewhat predictable. In more complex layers, the basic physical laws are still present but there are increasingly complex relationships between the basic structures. This complexity is amplified when atoms and molecules form structures such as cell membranes and biological organisms. Extend this to the degree of complexity present in a human being, and it becomes clear that incredibly sophisticated relationships, feedback loops, webs of communicating neurones and neurochemicalsexist. This makes, sensible or complete explanations, or reductions, in terms of lower strata increasingly difficult and often invalid.Stratification indicates that our reduction of a patient to a series of scan images and blood results is inadequate. Critical Realism suggests that there is no limit to the number of layers – for example we could position a ‘society’ layer at the top or a ‘quantum physics’ layer to the bottom, with more to come.

Concept 3 – Novel properties occur in complex systems: Emergence

Within these complex structures unusual and unpredictable properties arise, properties which are not present in the basic building blocks of these structures or organisms. This is harder for us to apprehend because we may have assumed a fallacy: that larger things can always be explained in terms of smaller, simpler things. Emergent properties arise in complex systems due multiple non-hierarchical and non-linear relationships between components of the system. The whole is greater than the parts. Emergent properties are easily observable by scientists, for example the behaviour of a bubble, or cell membrane. Theseproperties are not present or always predictable at lower levels of organisation. One arguable example might be consciousness, which defies explanation in terms of the simpler components of the brain10 It is already established that emergence can be a useful and powerful concept in primary care 11

A crucial insight of emergence it the possibility of emergent properties “ acting back” on simpler layers of the structure. If we think back to our patient with chronic pain we have all observed how a change in the patient’s ideas  can change their physical parameters. If we can convince that patient that “pain does not always indicate tissue damage”, we may get them to exercise more, relieving muscle spasm and increasing functional strength: Ideas and cognition act back on material reality. In a critical realism sense, if something can affect the natural order, it can be considered real.

Concept 4 – Scientists, and science, are fallible

GPs readily accept the limitations of practice; that even the best science can be limited, prone to revisions and error. Sometimes one of our theories attracts so much counterevidence it has to be completely revised. We hope that our science gets closer to the truth as time goes on, but we can only apprehend science through the limitations of our cognition, language, present scientific instruments, and our interpretation of what their data means. In technical terms CR refers tothis as “Epistemological Relativism” – that our knowledge of truth is substantial, but fallibly observed, and always provisional. For example: Future functional scanning of a patient with pain may supersede our present anatomical scans and be more powerful?

Concept 5 – rational argument is worthwhile: Rational Judgementalism

This proposes that the human capacity to reason is not simply a survival mechanism, it is a credible approximation to the truth. A clinical discussion with colleagues from other specialities may well help us manage a patient with pain. Arguments, where well-constructed, are important and valid tools in furthering our knowledge. Critical Realists believe, I would suggest in common with most GPs, that all well conducted research and enquiry can, and should be acknowledged. Critical realism suggests these inclusive approaches were valid: butgives us a fresh and robust academic framework to rest this on.

The universe, and the ‘Primary care’ part of it, is not linear, predictable and ruled by deterministic laws which dictate our biological and psychological states. Neither is it a purely experiential one, where the patient’s perspective is the only valid one and can exist without any physical correlation. The patient’s story and their scans are part of one undivided person, and science must bring these together and critical realism may show us a way.

References 

1. ​Haase CB, Brodersen J, Bulow J. 8 The lack of ontological awareness in evidence-based medicine allows overdiagnosis. BMJ Evidence-Based Medicine. 2019 Jul 1;24(Suppl 1):A5–A5.
2. ​McCartney M. What has postmodernism done to evidence-based medicine? Br J Gen Pract. 2023 Oct 1;73(735):470–2. DOI: https://doi.org/10.3399/bjgp23X735201
3. ​Vogt H, Ulvestad E, Eriksen TE, Getz L. Getting personal: can systems medicine integrate scientific and humanistic conceptions of the patient? J Eval Clin Pract. 2014 Dec;20(6):942–52.
4. ​Caplan AL. Does the philosophy of medicine exist? Theoretical Medicine. 1992 Mar;13(1):67–77.
5. ​Stempsey WE. The philosophy of medicine: Development of a discipline. Medicine, Health Care and Philosophy. 2005 Jan;7(3):243–51.
6. ​Bhaskar R. A realist theory of science. York Books: Books; 1975. 258 p.
7. Pilgrim D. The Biopsychosocial Model in Health Research: Its Strengths and Limitations for Critical Realists. Journal of Critical Realism. 2015 Apr 1;14(2):164–80.
8. ​Fletcher AJ. Applying critical realism in qualitative research: methodology meets method. International Journal of Social Research Methodology. 2017 Mar 4;20(2):181–94.
9. ​Bhaskar R. The Possibility of Naturalism: A philosophical critique of the contemporary human sciences. 4 edition. London ; New York: Routledge; 2014. 238 p.
10. ​Tallis R. Aping Mankind: Neuromania, Darwinitis and the Misrepresentation of Humanity. 1 edition. Durham England: Routledge; 2014. 400 p.
11. ​Sweeney K. Complexity in Primary Care: Understanding its Value. 1 edition. Oxford; Seattle: CRC Press; 2006. 176 p.

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