Applied Phenomenology and the Phantom in the Mirror

Phantom limb pain is a universal phenomenon among amputees but modern medicine still has no consensus on an organic analysis of functional lived experience. I argue that the phenomenological analysis of Meurice Merleau-Ponty best explains why the use of a mirror to 'release' the absent limb remains the most effective treatment.

Introduction

Amputations are required by patients across the world to address serious threats to the rest of the body caused by diseases such as diabetes or else injuries, accidents and war. In 2017, an estimated 57.7million people globally were living with limb loss. Procedures to remove other body parts take place less frequently including eyes, the tongue, digits and the nose but often with the same disconcerting experiences for patients. The phenomenon of ‘phantom’ sensations, particularly pain, sensed as originating from the amputated limb or body part is a side effect experienced by 60% to 80% of amputees. Here, I will argue that within the phenomenological analysis of the embodied self, Meurice Merleau Ponty in Phenomenology and Perception (1945) offered a prescient phenomenological view of the peculiar lived experience and apparently contradictory discriminations within the consciousnesses of amputees who continue for long periods to sense the absent limb as ‘quasi-present’. I will contend that his approach helps  us to understand why a novel and effective therapy discovered in 1996 that uses only a mirror to produce better outcomes than many drug-based treatments by enabling patients to slowly and holistically integrate the loss of the absent body part. Looking at other pharmacological treatments for–and interpretations of–phantom limb pain (hereafter PLP), the effectiveness of mirror therapy when viewed phenomenologically reveals how the view of the mind-body, psychic-physiological integration proposed by Merleau Ponty can also help to elucidate the underlying processes, perceptions and treatments of other psychophysical conditions. Such conditions arise where the contents of a patient’s memories and consciousness are inextricably intertwined with their phenomenological experience of bodily symptoms in ways that mechanistic medicine is not yet capable of explaining convincingly.

Phantom Limbs: a History of Bewilderment . 

The phenomenon of absent limb sensations was first described in any detail by a French military surgeon, Ambrose Paré, in the 16th century who was shocked by–and sympathetic to–the traumatic experiences of amputees. Paré on methods to address catastrophic trauma in war and reputedly regarded surgery as a last resort (unlike many contemporaries). He also worked on the development of prosthetic limbs to aid ‘normal living’ and his accounts of the sensations of patients is correspondingly sympathetic. (Five Early Accounts Of Phantom Limb In Context: Paré, Descartes, Lemos, Bell, And Mitchell; S Finger, P H Meredith; Neurosurgery; 2003, Mar;52(3):675-86).  However, the most complete pre-20th century investigation of the phenomenon was by Silas Weir Mitchell, an American military surgeon who worked extensively with amputees during the American Civil War. Mitchell first used the term ‘phantom’ to describe sensations in absent limbs citing accounts from dozens of interviews with patients. One such account is particularly relevant in the context of this essay. It related to a horseman whom Mitchell describes thus [ibid p9]:  

“A very gallant fellow, who had lost an arm at Shiloh, was always acutely conscious of the limb as still present. On one occasion, when riding, he used the lost hand to grasp the reins, while with the other he struck his horse. He paid for his blunder with a fall…”

Within the early literature, certain facets of patients’ descriptions of their lived experience of phantom sensations recur, describing sensations that simply do not fit with contemporaneous medical understanding of how nerves and nociception works. The word ‘phantom’ applied by Mitchell speaks to the ghostly nature of these sensations. Commentary is accordingly marked by degrees of bewilderment on the part of the doctors describing patients’ clear descriptions of their symptoms without a scientific or medical framework to understand how such sensations could be occurring. The limb is missing and the afferent nerves are severed but instead of localised pain at the stump, the pain and sensation present to the consciousness of the patient as emanating from a persisting spatialised limb. Most striking of all, the nerves which would have been active at the periphery of the missing limb–and so responsible (if they were present) for transmitting sensations such as the clenching or movement of a hand–are entirely absent but still providing the same phenomenological sensations. The wheel is going round but the hamster is missing! 

In an example quoted by Finger et al, the German physiologist Johannes Müller in his 1834 Handbuch der Physiologie uses an example where the whole body perception of weather prompts specific phantom sensations that cannot relate to stimuli at the stump:

“A toll-keeper in the neighborhood of Halle, whose right arm had been shattered by a cannon-ball in battle, above the elbow, twenty years ago, and afterwards amputated, has still, (in 1833), at the time of changes in the weather, distinct rheumatic pains, which seem to him to exist in the whole arm; and though removed long ago, the lost part is at those times felt as if sensible to drafts of air”.

The mystery caused by psychophysical symptoms throughout historic PLP literature is indicative of the post-enlightenment drift away from the individuation of experience and towards diagnostic and therapeutic progress via standardised measurement, quantification, isolation and targeted treatment of symptoms (cf. Dialectic of Enlightenment; 1947; T Adorno, M Horkheimer). Standardisation in the analysis of phantom limb means the causal model where nociception emanates from nerves in a standard stimulus/response pattern: viz, this nerve senses damage, the brain registers this pain.  This model was first proposed by Dr Wilder Penfield following experiments to ‘map’ somatic and sensory pathways from body parts onto the brain using first a 2D then a 3D a homunculus representation where the size of body part represented the concentration of sensory nerves (ie making the hands and lips larger than the legs). 

The Wilder Penfield 3D Somatosensory Homunculus, based on the 2D model of 1937, maps the concentration of nerves from body parts proportionately onto the cortices resulting in a homunculus where sensitivity is mapped to relative part size.

Since Paré’s early description (and there may be others from earlier), the problem for the stimulus/responses model is that the detailed phenomenological experiences are not felt at the stump but within the vacant spatiality of the missing limb. Generalised or localised pain would not present a problem but autobiographical sensations of hands clenching, shrapnel striking and positional sensation can be understood by the nociception model only via the delivery of these sensations from nerves that are no longer present. 

The benefits of an applied phenomenological analysis of phantom sensations become clear in this apparent contradiction. The mystery for the medical profession and amputees alike lies in the disconnect between the concrete qualitative tactile experience of the amputee and the visual/medical evidence for doctors: the limb is sensed and reported as there but it is clearly not there. A phenomenological perspective places the primacy of amputee’s perception within their embodied experience of the world since foetal development. It is so deeply intertwined in the memory and sensation of the body that its removal does not turn it ‘off’ as if a part from an engine had been removed.

Coping with the loss is a journey of acceptance, reinterpretation and integration incorporating memory and consciousness not just the blocking of neurological data. The lived experience of the individual is utterly central and neither a physiological or a psychological explanation will do.  As Merleau Ponty notes: “The phantom limb is not the mere outcome of objective causality, no more is it a cogitatio; it could be a mixture of the two only if we could find a means of linking the ‘psychic’ and the ‘physiological’ … to each other to form an articulate whole …” (The Phenomenology of Perception; 1946; Pt 1, p.77).

Before approaching Merleau Ponty’s thinking more deeply, it is worthwhile examining

(i) the more recent neurophysiological literature on PLP and the lack of accepted explanations or treatments when science is faced with the many apparent contradictions of phantoms.

(ii) the recent emergence of an effective, non-invasive, non-pharmacological therapy for PLP using only mirrors and movements.  

PLP research and therapies

If a goal of medicine is the search for effective patient-sympathetic treatments for illness and injury, it has singularly failed in respect of PLP.  In their paper Phantom Limb Pain: A Literature Review in 2018, Amreet Kaur and Yuxi Guan from the California School of Podiatric Medicine conclude that “there is still no detailed explanation of its mechanisms.” Likewise, Sharon Weeks et al in the 2010 paper Phantom Limb Pain: Theories and Therapies reach a similar stark conclusion:“We continue to lack evidence and a clear explanation as to why some individuals develop PLP and some do not… and what molecular and biologic mechanisms are at work. With the exception of opioids and mirror therapy, many of the other reported treatment modalities lack robust studies to support their effectiveness. 

Weeks et al consider a range of theories to explain PLP including: 

• The Body Schema theory proposed by Head and Holmes in 1912, where the internal map of the body is inclined to retain an intact image of the body regardless of its true appearance or condition. This theory hits serious problems with the condition of Allochiria (NB discussed later under Merleau Ponty’s analysis of this condition).
• Cortical Reorganization and Neuroplasticity theories whereby cortical areas are annexed by neighbouring representational zones such that what is missing is ‘taken over’ by what remains - including the sensory input from amputated digits by their adjacent digits.
• Neuromatrix theory proposed by Ronald Melzack where the internal representation of the body has multiple perceptual inputs comprising a ‘neurosignature’ which becomes abnormal when various inputs from the limbs cease causing phantom limb sensations.  Heavy criticism has resulted from the fact that this theory cannot deal with pain-free qualitative sensations from phantom limbs. 
• Peripheral Nervous System theories which include a range of proposals indicating referral of sensation from residual limbs to phantom limbs. Interestingly, Weeks et al mention the use of prostheses to rehabilitate patients based on this theory with the conclusion that these may “help maintain a body schema in which the phantom limb remains similar to the intact one, as such a representation is necessary for movements to be carried out properly.”

Each of these theories provides some explanatory power but each struggles to cope with counter-examples from the lived experience of amputees because they frame their sensory experiences (including pain) in autobiographical terms that relate to a limb still present to the senses and the memory. Their phenomenological experience takes primacy over what is visible and measurable to science in its search for neurological or biological explanations when the true explanation rests rather within the consciousness of the patient.  

Phenomenology is powerful in respect of phantom limbs because its goal is to uncover the structures of consciousness from the lived experience of the patient, not to find causal roots of that lived experience by tracing sensations back to discrete components of the brain and body. To use an analogy,  looking for a medical mechanism to explain what patients feel is akin to looking at five blocks removed from a collapsed Jenga tower and trying to use them to understand the structure of the tower and the nature of the collapse: the parts cannot reveal the whole. 

Merleau Ponty’s philosophy of the body is based upon an understanding that the whole has to be taken as such: an intimately integrated intentional movement towards the world, not parts acting quasi-autonomously.

Within Weeks et al’s paper, a section entitled ‘Additional theories’ examines at the work of Ramachandran and Hirstein (at a time when they had recently discovered mirror therapy) into a ‘multifactorial model’ for PLP. This proposes that at least five different sources (NB. in fact, these are ‘theories of sources’) contribute to PLP experience. Weeks et al comment that “The most important aspect of the [multifactorial] theory is the emphasis that all 5 components work together and reinforce each other.” [my italics].  This is significant because the philosophical approach I will consider next starts from the point that the ‘whole descends to the parts’ in the embodied self–the position that science finds itself dragged towards by the explanatory failure of analysis to date.

Mirror therapy for PLP - a phenomenological breakthrough

In 2010, V. S. Ramachandran and D. Rogers-Ramachandran who had both been highly active in the study of PLP for some years introduced a form of therapy that relied on a form of virtual reality to help amputees integrate their loss by restoring the visual appearance of the phantom in tandem with exercises. They placed a mirror vertically on a table of hand amputees so the reflection was superimposed where the patient ‘felt’ the phantom hand.  on the felt position of the phantom. They found that 60% of patients who moved the normal hand and then ‘saw’ the absent hand apparentingly moving also felt kinesthetic sensations in the phantom. This even occurred in a patient who had not felt the phantom for ten years previously . The same patient repeated the exercise and subsequently enjoyed the permanent ‘disappearance’ of the phantom. Most strikingly, in four of five patients who regularly experienced involuntary painful clenching spasms in their absent hands the sensations ceased after repeated practice of ‘opening’ the  phantom hand and seeing this taking place in the mirror. 

They were also able to bring about other therapeutic effects that they categorise as synaesthesia in their patients using the mirror box leading to their conclusion that the adult brain is loaded with latent plasticity, able to adapt very rapidly given such holistic experiences that reintegrate the felt sensations in the phantom with the apparent response in the hands they can ‘see’, even though these are clearly known to be reflections. 

Among their conclusions, they propose that: 

“…there must be a great deal of back and forth interaction between vision and touch, so that the strictly modular, hierarchical model of the brain that is currently in vogue needs to be replaced with a more dynamic, interactive model, in which ‘re-entrant’ signalling plays the main role.”

This speaks directly to the phenomenology of Meurice Merleau Ponty in the recognition that scientific method alone tends to develop taxonomic, hierarchical and causal theories of symptoms.  In many cases, such approaches can work well but when the consciousness and memories of patients are so intimately tied in with the sensation of their body and mind as an integrated self–as with pyschophysical sensations–the failure to see the wood for the trees besets medicine. 

Mirror therapy in its simplest lay terms, provides visual feedback to the patient congruent with the quasi-presence that they experience phenomenologically through the phantom pain and sensation. Clenched hands can be seen and felt unclasping simultaneously allowing the whole body to ‘release’ the sensation. There are many subsequent theories of brain mechanisms to account for this. The key question is whether simply paying attention to what PLP patients have always felt might have led to mirrors rather than drugs.

Merleau Ponty’s analysis of phantom limb sensations

In The Phenomenology of Perception, Merleau Ponty aims to bridge the apparently insufficiency of either physiological or psychological explanations to account for phantom limb symptoms as experienced by amputees with an argument that marries both the physical and psychic elements within his theory of a body that ‘moves towards the world’ in an intentional manner providing ‘situational not spatial positionality’. This approach unifies the parts, senses, sensations and pathology of the body in contrast to the scientific method of positing each part as distinct and thus analysable via the stimulus/response testing paradigm of parts in isolation. 

Unlike Husserl, Merleau Ponty’s phenomenological approach focuses on the body as a unit rather than as an object perceived by the mind. He also uses a range of documented physical and psychological conditions to elucidate his argument. Notably, he considers the implications of allochiria and anagnosia for the classical physiological interpretation model of the body schema–the collection of processes proposed by Sir Henry Head as registering the posture and relative position of our body parts in space which is updated as we move (H. Head, 1920; Studies in Neurology. Vol.2. OUP). Allochiria is the sensation of stimuli in the part on one side of the body being felt in the same body part on the opposite side, while anosagnosia involves not sensing a body part as belonging to the body. With allochiria, a person may feel the stroking of their left hand in their right hand. This makes it a good example of the shortcomings of a body schema mapped discretely within the brain. If the schema were simply a summary of bodily parts in their respective positions, then allochiria would require us to believe that the left hand’s representation in the schema is somehow magically superimposed or folded over onto the right hand, reassociating left with right. Instead, Merleau Ponty proposes a “global awareness of my posture in the inter-sensory world” that classical physiology and psychology fails to capture through positional or associative mechanisms. In this unified body, consciousness of location results from the intentionality and movement of the whole body towards its environment. The body’s experience descends from the whole to the parts. It does not ‘undergo’ the world but explores it with motion towards it and the discovery thereof. (ibid p.132). 

This definition of spatiality flows into his analysis of phantom limb. A physiological explanation cannot suffice because the sensations experienced are inconsistent with the stimuli occurring only in the precise location where those nerves end at the stump where the limb was separated. Neither will a psychological explanation do; if the sensation of the limb as still present were purely a psychological phenomenon from the unwillingness to ‘let go’, then the phantom sensations would not disappear when the sensory nerves that run to the brain are severed–as we know is the case. [ibid p.105]

Merleau Ponty’s philosophy thus understands the body as an organism living in an open situation that ‘moves towards the world’as a whole with intentionality, spatiality, motricity–and so discovery–acting in concert through motion.  The absence of the limb therefore creates a dissonance because the experience is not propositional (in the form “I think that…”) despite what her eyes tell the patient because her sensory experience is of presence, as is her memory and persistent intentionality in the quasi-presence of the limb as per Mitchell’s horse rider example quoted earlier.  

As Merleau Ponty says, the stimulations coming from the stump…

“... keep the amputated arm within the circuit of existence. They mark off and reserve its place, ensure that it has not been annihilated and that it continues to count for the organism; they maintain a void that the history of the subject will fill in.” [my italics] [ibid p.116]

Neuroscience, medicine and PLP

The scientific empiricism in the literature review quoted above differs from Merleau Ponty’s phenomenological approach in that science lacks focus on phenomena, presences and subjective ‘givens’ which may not accord with scientific understandings of reality but are the essence of personal subjectivity.  Phenomenology of Perception seeks to sidestep the standard mechanisms of medical cause and effect, instead seeking to clarify the human meaning of the phenomena presented to–and through–the embodied self. 

 In his 2005 paper, The Phenomenological Movement and Research in the Human Sciences, Amedo Giorgi M.D. says:  

“The introduction of phenomenology on the philosophical scene … is a shift of focus from physical nature, cause-effect analyses, impersonal forces and their manipulation and control to human subjectivity, intentionality, the meaning of actions, and the freedom and responsibility that intrinsically belong to them.”

Beginning with Husserl, phenomenologists argued that consciousness is radically different from physical things. However, in science since the enlightenment, as described so poetically by Adorno and Horkheimer, the project of measurement and standardisation has taken the body as another object: flesh separate from consciousness, implicitly sustaining a Cartesian position in the mind-body problem. Merleau Ponty seeks to remove the delineation and find the bridge between the psychical and physiological that in turn casts the clearest light on the peculiarities of phantom limb pain and sensations. 

Science can’t examine the memories of a patient about her missing limb or relate the observed neurophysiological data to her lived sensation of nails digging into the palm of a missing hand. This type of memory, intimately intertwined with lived sensations, is not just a recollection of past events or facts, it is a much deeper holistic sense of spatiality and motricity within the embodied self that Merleau Ponty identifies.  

The central question therefore is not whether medicine and science will or will not eventually be capable of a convincing naturalistic explanation of the mechanisms involved in PLP. Rather, it is whether more serious attention to the lived experience of patients using applied phenomenology could yield better understanding of–and treatments for–a condition that affects tens of millions of people in the world now and hundreds of millions over the course of medical history. This question goes to the heart of medical science when it is based on the isolating, quantifying, measuring and testing using a stimulus/response, cause/effect model only.  

Modern understanding of the mechanisms of memory have already moved in this direction. A bombing victim with a memory of the strike of shrapnel and related sensations goes on to experience that memory as ‘real’. Autobiographical memory is now understood as not simply generating floaty representations of past events; rather, memories provoke the same internal enzyme and adrenal responses as the original event: our whole body reacts as if the memory were ‘real’. In this respect, Merleau Ponty’s work resonates with the very latest neuroscience: patients’ responses to the sensations of the absent limb are felt as real by patients precisely because the whole body-mind experience is in many respects the same. Only reasoning stemming from the higher level processing of visual data and the memory of amputation tells the patient any different and reason vs felt experience is not strong enough. This is where a phenomenological view as nuanced as Meurice Merleau Ponty’s provides explanatory power while, for medicine, the mechanisms and etiology remain a mystery.  

Conclusions…

By positing the body as an object among objects–which we can thus dissect and study as we do the cogs in a machine–traditional medicine moves inexorably towards a misguided representation of the body as a co-located collection of discrete parts and functions rather than an intertwined, embodied whole.  The case of phantom sensations from absent body parts is thus a salutary case study of the role that applied phenomenology can play in helping medicine move away from the results only of lab experiments towards the integration of the lived experience of those it treats.  Doctors cannot make sense of the patient’s sensations when it is clear to all that the arm is not there but the efficacy of simple mirror therapy points to the fact that neither can patients. Knowing it is not there via the eyes is insufficient to allow patients’ bodies to accept its absence when this knowledge is set against the intimate power of its felt presence and foundational presence in memory. Allowing them to learn to let go by placing it back in situ using an illusion enables a slow, calm departure rather than that which was forced on the body by amputation.  

Meurice Merleau Ponty’s phenomenology stresses the primacy of perception and the embodied self.  It is a perspective quite different from that of the scientific view of the body given in physiology and psychology but by focusing on lived experience it helps to provide a bridge to better treatment not just for phantom limbs but for cancer,  motor neurone disease, MS and paediatric conditions by placing the patient’s true experience back in the centre of the mix. 

No naturalistic explanation of the sensations of phantom limb has yet emerged via traditional medical research. Neither did effective treatments until Ramachandran’s work with mirror boxes. The huge medical literature on the subject is evidence of a struggle to reach any compelling or even integrated naturalistic explanation. In effect, explanations tried to ‘reverse engineer’ the phenomenology of phantoms back into medical cause and effect or else psychological repression or rejection of loss. Merleau Ponty argues convincingly that such a project cannot work without a different view of the body; a phenomenological view. Biochemistry and neuroscience cannot unpack from neurons and dendrites to the memories and qualia of lived experience that makes the limbs ‘quasi real’ for patients after it has gone. Ramachandran’s mirror therapy success opens a gateway to show how applied phenomenology can fill in the gaps that medicine creates for itself through its predominantly naturalistic method by focusing on what the patient feels, sees and needs as an integrated embodied whole.

-ends-

References

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