Phantom Limbs When we ask ourselves what is knowledge (as we do when we are engaged in the process of philosophy) we are effectively asking what is our relationship with the world. V.S. Ramachandran - as is the norm for philosophers - asks the question about our relationship to the world by using what at first might seem to be a relatively trivial issue, or at least one that very few of us shall ever actually have to worry about, which is the question of phantom limbs, the subject of both Ramachandran's interest and our own.

The desire to know and the desire to discover are essentially active, even aggressive actions taken on the part of consciousness to acquire pieces or aspects of the world. When we seek knowledge, we seek to take into our minds (and so to take into our bodies physically) something that exists in the world. We seek through knowledge to dismantle the world and so to come to possess it.

This is of course an ongoing concern of philosophical discourse. Jean-Paul Sartre, for example, argues for this model of knowledge, arguing that it is a sort of black hole, something that uses the primordial forces of cognition and reason to draw the world into the self. We construct ourselves out of bits of the real world; thus we cannot in any sense argue that knowledge and self are different entities since we actively create who we are through our active acquisition of knowledge. Knowledge is the process of choosing which pieces of the world to incorporate. Thus knowledge is the process of making ourselves responsible for the world around us. In other words - or at least this is the Sartrean position, and Ramachandran would not necessarily disagree - is not merely a collection of facts. It is the active way in which we interact with the world around us. It is linked to our state of being.

Related to this question of the nature of knowledge is of course the question of what is the nature of the self. The question of self is one often expressed in philosophy as the question of "being" (as opposed to, or in addition to) "knowing" and has been of primary concern for many if not most philosophers, who have argued that whatever certainties may be possible in our world must come from an understanding of our authentic self, the core of our individuality.

But questions of the self are not so simple as they first seem - and they are hardly seemingly simple even at first glance. And it is to suggest at the complexity of one of the most seemingly simple ontological questions (Who are we in the sense of we do our bodies begin and end) that Ramachandran takes up the issue of phantom limbs.

We should first here define the concepts of phantom limb and phantom pain:

Imagine having your arm cut off and still being able to feel where your arm used to be. That is what it is like to have a phantom limb. People with this condition feel that the limb (an arm or leg) that was removed is still present and they often feel pain, and sometimes pleasure. Usually the pain is mild and is only a small distraction. However, some people describe the pain and other symptoms of phantom limb as totally unbearable. When a person experiences pain from phantom limb, this is often referred to as phantom pain.

More commonly, people with phantom limb feel other abnormal sensations in the missing limb besides pain. The pain and abnormal sensations are typically in the form of stabbing, cramping, burning, or crushing sensations. Warmth, itchiness, and squeezing sensations are other symptoms that are commonly reported. These sensations can occur continuously or they can occur only some of the time. Stress usually makes the symptoms of phantom limb worse

People with phantom limb usually perceive the arm or leg to be in a certain position, and sometimes, the arm or leg is perceived to move. They may also feel that when a different body part is touched (such as the face) that a limb is being touched (such as an arm). Some people with phantom limb experience a symptom known as telescoping, in which the imagined limb slowly shrinks ((http://www.medfriendly.com/phantomlimb.html).

There are clearly purely medical (i.e. therapeutic) issues to be dealt with in terms of phantom pain. But the idea of phantom limbs is a more salubrious one and allows us - or rather allows Ramachandran to examine how it is that our interior sense of self matches some objective measure of that self. We think that...

But this is in fact not the case.
Recently, Ramachandran and Rogers-Ramachandran used a Mirror Box Procedure (MBP) to treat phantom limb pain. In this procedure, upper-limb amputees placed their intact arm into a box, with a mirror down the midline, so that when viewed from slightly off-center, the reflection of their arm gave the impression of having two intact arms. Individual differences were observed in the extent to which participants were susceptible to the MBP illusion. Moreover, although this technique had quite dramatic therapeutic value for some people, it was only moderately effective, or completely ineffective, for others. More worriedly, some investigators have recently found that using the MBP to induce illusory body experiences can actually worsen phantom limb pain in people who have had an amputation (MacLachlan, Desmond & Horgan, 2000).

This experiment is linked to another one that Ramachandran has performed and which is - from a philosophical point-of-view - even more challenging. It might be relatively easy to dismiss the epistemological significance of phantom limb pain because it is in some sense unnatural; but Ramachandran and Blakesee have demonstrated that each one of us is subject to such illusions. We can all be convinced - quite easily, albeit temporarily - that we are Pinocchio.

The ENP described by Ramachandran and Blakeslee aimed to produce the illusion that the participant's nose had stretched approximately 3 ft in front of his or her face [10]. The blindfolded participant was seated directly behind a volunteer, both of whom were facing in the same direction. The participant allowed the experimenter to passively manipulate his or her left hand so that the index finger was used to touch the volunteer's nose in a rhythmic tapping sequence. The experimenter simultaneously and synchronously tapped the participant's nose in the same manner. After 1 1/2 min, the participant was requested to give an open-ended description of his or her experience. The experimenters subsequently rated responses on a 3-point ordinal scale, where a score of zero indicated no experience of the illusion, one indicated the intermediate-strength illusion that the participants were touching their own nose, and two indicated a stronger sense of illusion that the participants experienced their own nose as stretched in front of their face (MacLachlan, Desmond & Horgan, 2000).

These questions may sound familiar - and we have indeed heard then before, from Rene Descartes, although Descartes, of course, comes up with an entirely different answer to the question of the significance of such phenomena (he does not of course address them directly, but his work can and should be extended to encompass such as argument. The central guiding principles for Descartes' own life was never to accept as true anything that he had not himself determined to be true. An adherence to this high standard of intellectual activity may be seen to be the central concern and purpose of his Discourse on Method. He begins this work, as others, from a position of methodological doubt, which seems to him to be the most and indeed the only appropriate position from which he might write. The work develops into an investigation into the nature of knowledge and into the ways in which knowledge and doubt are bound to each other and the ways in which the opposite of Truth can be seen in many cases to be not falsity but doubt.

Descartes argues that one cannot be certain of anything until one has doubted it; this might seem to be a contradictory stance but is so only for a moment. We ourselves have each experienced this phenomenon, of doubting something, then determining that it is in fact true, and then believing afterwards in its truth far more profoundly than we would have if we had not had to work out the proof for ourselves. Ramachandran offers the case of phantom pain to be of exactly the same type of experience - with the key difference that we cannot trust even the most intimate sorts of proof.

We may think we have an arm, but we may not. And if certainty cannot be had even in so small a thing as this, then Decartes's methodic doubt (and by extension, of course, all of Empiricism) is on shaky ground indeed.

It is imperative to note that Descartes's doubt was not simply that of the cynic but rather what the philosopher termed "methodic…