From treating the body as a machine to the contemporary obsession with neuroscience, hidden philosophical assumptions are exposed when we think about pain and its treatment. A new conceptualisation called the enactive approach brings together advances in phenomenology and cognitive science and puts the patient and their future at the centre. Peter Stilwell and Sabrina Coninx make the case for a new medical paradigm for pain. 

Acute pains, such as the immediate unpleasant experience of stubbing a toe, last for a relatively short duration. In contrast, pains that recur or persist are labelled as chronic and are associated with enormous personal and economic impacts. Unfortunately, we are far from understanding why many pains persist and how they are best treated. Chronic pain often has no apparent injury or pathology to help explain its occurrence, leaving many patients asking: why does it still hurt?

Common responses to this question are viewed as unsatisfactory to patients. People with chronic pain are often left feeling confused, broken, and frustrated after receiving differing explanations and promises of cures or fixes that don’t materialize. Further, pain without a demonstrable objective problem in the body is viewed by many outsiders (e.g., clinicians, friends, family) as less real, and people are stigmatized as a result. Feelings of shame, invalidation, and suicidality among people with chronic pain are clear indicators that we need to do better.

We suggest that looking to philosophy is a useful starting point. Consciously or subconsciously, every pain researcher and clinician has a philosophy of pain containing assumptions that influence how they conceptualize, assess, explain, and treat pain. These assumptions are also contagious in the sense that they can be transmitted to patients, which, for better or worse, may influence how they view themselves, their body, and engage with their environment. Important pain theories have been proposed, but they come with core assumptions, some of which are problematic. This article exposes some of these assumptions about pain and introduces new ways we can think about pain and its management. Let’s start by reviewing some landmark pain theories and enduring assumptions they have left us with.

"Consciously or subconsciously, every pain researcher and clinician has a philosophy of pain"

Cartesian assumptions: The machine-like body

Descartes, the famous 17th-century philosopher known for separating the mind and body (Cartesian dualism), had a mechanical view of the body. Although he had some nuanced ideas about pain and the interaction between the mind and body, society latched onto his mechanistic writings that portrayed pain as the result of disturbed bodily tissues that essentially tug physical tubes connected to the brain (Descartes, 1633/1972). In other words, he viewed pain like a bell that rang in the brain when a string was pulled in the body. This view entails two central assumptions. First, there is a linear relation between disturbance in the body and the resulting pain: increased disruption or tissue damage (tugging harder on the string) equals increased pain (bell rings louder). Second, the brain is only a passive receiver of signals from the body, playing no active role in the modulation or generation of pain. Therefore, we simply need to identify the bodily cause of pain and act upon it to treat pain. The body is treated like a mechanical clock and pain is the indicator of a broken gear that needs to be fixed.

Although these ideas are centuries old, similar assumptions are still held today with serious implications. When clinicians look for the ‘root cause’ of pain or for a clear bodily issue and cannot find one, they may view the patient’s pain as less real: it is all in the patient’s mind. Even when a problem is found and ‘fixed’, pain often persists. People end up feeling hopeless and stigmatized as they have no credible explanation for their pain.

Melzack and Wall: Pain is more complex

In the 1960s, Melzack and Wall made foundational contributions that challenged linear and mechanical approaches to pain. They made the important distinction between the experience of pain and nociceptive signals generated from stimuli that damage or threaten bodily tissues. Their landmark Gate Control Theory (Melzack & Wall, 1965) helped make sense of the variable relationship between bodily injury and pain: increased tissue damage does not always mean increased pain and vice versa. Contrary to earlier theories, they proposed that signals ascending to the brain do not take a simple path but are modulated by a ‘gate’ at the spinal cord. This gating system can be opened or closed depending on a variety of factors. This was a massive contribution as it fostered an appreciation that factors beyond the peripheral tissues may influence the experience of pain. This includes attention, anxiety, stress, past experiences, and personal meanings shaped by different contexts.

Melzack later proposed the Neuromatrix Theory (Melzack, 1990) in which pain is understood as a multidimensional experience produced by a widely distributed neural network in the brain. Melzack made a huge impact on the field arguing that the brain doesn’t just passively receive nociceptive signals, but plays an active role. The idea that the brain generates pain helped explain complex phenomena in which there are no injury or danger signals coming from bodily tissues (e.g., phantom limb pain). Both the gate control and neuromatrix theories clearly reject the traditional Cartesian view.

Pain in the brain?

Melzack and Wall had nuanced views on pain; however, a take-home assumption for many was that ‘pain is in the brain’ and that we need to somehow ‘retrain the brain’ to get out of pain. These phrases rippled through clinics and the media (and still do today). Prominent figures in the 1990s and 2000s reinforced the general idea that we should focus on or prioritize the brain. For example, Nobel Prize winner Francis Crick declared that human experiences were no more than the actions of neurons and molecules; more specifically, we are ‘... nothing but a pack of neurons’ (Crick, 1995). Without diminishing the great contribution of neuroscientific research, we should, however, remain skeptical of this neurocentrism, especially given its implications for pain research and clinical practice.

Many now view chronic pain as a brain disease, and this has stimulated the pursuit of an underlying abnormality that can be effectively targeted and treated. While alterations in brain anatomy and connectivity correlate with the persistence or reoccurrence of pain, we should be careful not to take a reductionist perspective as it might have serious consequences. A narrow focus on the brain risks overlooking or trivializing non-neural factors and may impede the generation of knowledge gained by considering the inseparable relation between neural and non-neural, brain and non-brain-bound processes. Further, neurocentrism suggests that the dysfunctional brain experiences chronic pain, and patients often receive this to mean that it is ‘all in their head’ or that it is somehow their fault. There is a need for a ‘big picture’ framework that builds on the important contributions of Melzack and Wall and fully appreciates the lived experiences of people with pain and the complex web of factors involved. 

New paradigm: Enactive approach to pain

The enactive approach (Varela et al., 1991), commonly referred to as enactivism, is a movement that is rapidly gaining popularity as it offers new and interesting ways to think about the mind. There are now many strands of enactivism, and we find the work of  de Haan (2020, 2021) to have particular relevance to pain (Coninx & Stilwell, 2021). In general, enactivists endorse the idea that experience is not part of an immaterial mind abstracted from the living body (Cartesian dualism) or simply reduced to neural processes (neurocentrism). Instead, there is an appreciation of the whole person and how interactions in the environment (including other people) enact or bring forth experiences of ourselves and the world.

What does this mean for pain? In contrast to dualist or neurocentric explanations, an enactive approach to pain takes a simple yet surprisingly underused alternative: it is always the person (of course with a body and brain) in a certain context who experiences pain, and many factors are always shaping the experience. Therefore, we must address the entire person and their unique context to better understand and treat chronic pain. More specifically, an enactive approach to pain, as we see it, involves two central considerations: first, the generation and maintenance of pain involve the ongoing non-linear interaction of many factors inside and outside the body. Second, pain is understood in terms of a person’s active engagement with their environment and their perceived action possibilities. Let’s unpack these considerations.

Towards a complex and dynamic picture of pain

An enactive approach to pain suggests there are no singular causes of pain. The generation and maintenance of pain is more complex: there are always many mutually influencing processes and feedback loops between them that shape the person's experience. This includes physiological processes (e.g., neural activity), experiential processes (e.g., past experiences shaping current expectations), and socio-cultural processes (e.g., diagnostic labels and their common meaning). With an enactive approach, a person in pain is not considered a machine with strictly decomposable parts and linear processes that can be easily identified and fixed when they break down (e.g., finding and fixing a broken gear in a clock that stopped working). The initiating factors of pain may not be the same as the maintaining factors, and the effectiveness of a specific treatment cannot simply be reverse engineered to conclude what caused the pain. That is, as an alternative analogy (de Haan, 2021), we should rather think about the different factors involved as the ingredients of a cake (e.g., flour, sugar, eggs). Such physiological, experiential, and socio-cultural ingredients interact in complex, non-linear ways without a central control unit. We cannot reduce the generation and maintenance of pain to just physiological processes; like we cannot reduce a cake to just the flour. The way ingredients bring about pain are best understood in their interplay, that is, in the dynamic coupling of neural and non-neural processes and of the whole person in their environment.

Historical approaches largely sidestepped patients’ narratives and the role of the environment as they did not have causal relevance. There was a focus on the identification of ‘underlying’ physiological mechanisms, or the patient narrative was used simply as a means to uncover the physiological cause of pain. While it is essential to identify injury and pathology (e.g., fractures, infections, autoimmune conditions), the enactive approach also appreciates the patient’s perspective and that meaning shapes the experience of pain. For example, the belief that one’s body is broken or fragile can increase pain and disability. The environment also has important yet overlooked influence and can be the source of negative beliefs. Societal messages (e.g., ‘pain equals damage’ or ‘rest is best’) and invalidating interactions within the healthcare system can make pain worse. With an enactive perspective, processes contributing to pain are no longer restricted to the inner workings of the patient. Chronic pain is partly iatrogenic; society (including clinicians) need to be more accountable (Buchbinder et al., 2020).

"The effectiveness of a specific treatment cannot simply be reverse engineered to conclude what caused the pain."

We perceive ourselves and the world in terms of what we can do

Historically, we viewed our experiences of the world as an accurate representation of what is ‘out there’, independent of ourselves. Yet, the enactive approach challenges this view, suggesting that perception of ourselves and the world is shaped by what we can do. We largely perceive the world to act in and upon it. To get at this challenging idea, enactive thinkers use the term ‘affordances’ from James Gibson. Affordances are opportunities for action (good or bad) that the environment offers a species (Gibson, 1979). For example, members of different species might perceive the same object in different manners depending on their bodies, skills, and concerns. While humans might generally perceive a knee-high rock in terms of its sit-ability due to their body structure and the desire to rest, a snake may perceive the rock as a place to hide.

The unique set of affordances of an individual person is dynamic: they change based on sociocultural practices and one’s current skills, interests, needs, preferences, or intentions. Different situations or environments might call out for different actions, and different people might be responsive to different aspects of a situation, shaping the particular decisions that they make.

How does this relate to pain? People experiencing chronic pain generally perceive the world differently: their action possibilities shrink or change. Previous possibilities to act lose their attractiveness or become something to be avoided. Stairs may no longer be perceived as climbable, and a rock may no longer be experienced as something to be lifted or sat on. Lifting a rock might be perceived as a source of increased pain. Climbing stairs may be perceived as a source of embarrassment because it has become incredibly difficult due to pain. Chronic pain changes how people perceive themselves and their relationship with their environment. The body becomes an obstacle, everyday tasks are harder, and it can become impossible to see how one can continue into the future.

In enactive terms, chronic pain can permeate one’s life as they are no longer flexibly attuned to the environment in the way they were before (Coninx & Stilwell, 2021). Chronic pain is not simply acute pain that has failed to stop. The person may become stuck perceiving a world of closed-off or dangerous possibilities: more and more activities may be avoided. People can develop patterns where they stop believing in their bodily abilities. Unfortunately, messages from others may substantially contribute to this (e.g., blame, stigma, treating the body like a broken machine).

Clinical relevance

Many factors, many therapeutic options 

An enactive approach provides a general framework to guide personalized treatment. Clinicians are prompted to equally consider the person, their physical and socio-cultural environment, and the interaction between the two mediated by the body. While such complexity might appear overwhelming at first, it entails that there are many routes to change: there are many potentially effective interventions depending on the person’s needs and goals.

In principle, enactivism does not advocate for a particular kind of treatment. Instead, there is space for physiological interventions (e.g., administration of anti-inflammatory drugs), psychological interventions (e.g., cognitive behavioral therapy), and social interventions (e.g., peer support). We might receive the best outcomes when using multidisciplinary approaches that intervene at different points in the process of pain chronification and take advantage of the mutually reinforcing effects between them.

Finally, it should be emphasized that an enactive approach particularly appreciates the socio-cultural environment in which chronic pain develops, promoting empathetic communication and shared decision-making in terms of what treatments (if any) to pursue. This is a clear deviation from the ‘find and fix it’ approach that is still dominant and ascribes a different role to the clinician. 

Validating experiences and ‘opening up’ affordances

An enactive approach motivates that we should listen and validate a person’s experiences as real regardless of objective observations from a third-person or outsider perspective (Stilwell & Harman, 2019). This simple change may foster trust and mitigate stigmatization. This does not mean that clinicians (or others) cannot shape a person’s pain and action possibilities. Clinicians can guide people with pain to re-attune to their environment: a core aim of enactive therapy is to help people to become ‘unstuck’ by facilitating a process of ‘opening up’ or reconstructing a person’s perception of affordances.

Contrary to what Descartes led us to believe, increased pain does not always mean increased tissue damage. In many cases, a person with chronic pain can gradually and safely engage in activities that have been avoided; they can be sore but safe. A clinician can act as a guide by helping people break habitual patterns and to explore action possibilities that have been avoided or overlooked. Pain may reduce over time as a person adapts by re-engaging in valued activities or finding new and enjoyable activities.

To summarize, from an enactive perspective, the central goal of treatment is not to find and treat an underlying ‘cause’ but to help patients to better attune to their environments and to learn how to manage their pain. Effective treatment does not necessarily imply that the original cause of pain is eliminated or that the pain vanishes. Instead, treatment may help a person regain confidence in their body and view their future as offering opportunities for meaningful activities and possibilities.

References

Buchbinder, R., Underwood, M., Hartvigsen, J., & Maher, C. G. (2020). The Lancet Series call to action to reduce low value care for low back pain: an update. Pain, 161(Supplement 1), S57–S64. https://doi.org/10.1097/j.pain.0000000000001869

Coninx, S., & Stilwell, P. (2021). Pain and the field of affordances: an enactive approach to acute and chronic pain. Synthese. https://doi.org/10.1007/s11229-021-03142-3

Crick, F. (1995). The astonishing hypothesis: the scientific search for the soul. Simon & Schuster.

de Haan, S. (2020). An Enactive Approach to Psychiatry. Philosophy, Psychiatry, & Psychology, 27(1), 3–25. https://doi.org/10.1353/ppp.2020.0001

de Haan, S. (2021). Bio-psycho-social interaction: an enactive perspective. International Review of Psychiatry, 33(5), 471–477. https://doi.org/10.1080/09540261.2020.1830753

Descartes, R. (1633/1972). Treatise of man (Trans. Thomas Steele Hall). Havard University Press.

Gibson, J. J. (1979). The ecological approach to visual perception. Houghton-Mifflin. https://doi.org/10.4324/9781315740218

Melzack, R. (1990). Phantom limbs and the concept of a neuromatrix. Trends in Neurosciences, 13(3), 88–92. https://doi.org/10.1016/0166-2236(90)90179-E

Melzack, R., & Wall, P. (1965). Pain Mechanisms: A new theory. Science, 150(New Series), 971–979.

Stilwell, P., & Harman, K. (2019). An enactive approach to pain: beyond the biopsychosocial model. Phenomenology and the Cognitive Sciences, 18(4), 637–665. https://doi.org/10.1007/s11097-019-09624-7

Varela, F., Thompson, E., & Rosch, E. (1991). The Embodied Mind: Cognitive Science and Human Experience. MIT Press. https://doi.org/10.1111/j.1468-0149.1965.tb01386.x