Hallucinations

“Of course,” added James, “such an experience as this does not connect itself with the religious sphere … [and] my friend … does not interpret these latter experiences theistically, as signifying the presence of God.”

But one can readily see why others, perhaps of a different disposition, might interpret the “sure knowledge of the close presence of a sort of mighty person” and “a startling awareness of some ineffable good” in mystical, if not religious, terms. Other case histories in James’s chapter bear this out, leading him to say that “many persons (how many we cannot tell) possess the objects of their belief not in the form of mere conceptions which the intellect accepts as true, but rather in the form of quasi-sensible realities directly apprehended.”

Thus the primal, animal sense of “the other,” which may have evolved for the detection of threat, can take on a lofty, even transcendent function in human beings, as a biological basis for religious passion and conviction, where the “other,” the “presence,” becomes the person of God.

1. It is likely that there was popular or folk knowledge of the phenomenon long before there were any medical descriptions.

Twenty years before Weir Mitchell named phantom limbs, Herman Melville included a fascinating scene in Moby-Dick

, where the ship’s carpenter is measuring Captain Ahab for a whalebone leg. Ahab addresses the carpenter:

Look ye, carpenter, I dare say thou callest thyself a right good workmanlike workman, eh? Well, then, will it speak thoroughly well for thy work, if, when I come to mount this leg thou makest, I shall nevertheless feel another leg in the same identical place with it; that is, carpenter, my old lost leg; the flesh and blood one, I mean. Canst thou not drive that old Adam away?

[The carpenter replies:] Truly, sir, I begin to understand somewhat now. Yes, I have heard something curious on that score, sir; how that a dismasted man never entirely loses the feeling of his old spar, but it will be still pricking him at times. May I humbly ask if it be really so, sir?

It is, man [says Ahab]. Look, put thy live leg here in place where mine once was; so, now, here is only one distinct leg to the eye, yet two to the soul. Where thou feelest tingling life; there, exactly there, there to a hair, do I.

2. The importance of first-person accounts was emphasized by William James in his 1887 paper “The Consciousness of Lost Limbs”:

In a delicate inquiry like this, little is to be gained by distributing circulars. A single patient with the right sort of lesion and a scientific mind, carefully cross-examined, is more likely to deepen our knowledge than a thousand circulars answered as the average patient answers them, even though the answers be never so thoroughly collated by the investigator.

3. The reason for this was not to be clarified until a century later, when it became possible to visualize, with fMRI, the gross changes in the brain’s body mapping that could occur after an amputation. Michael Merzenich and his colleagues at UCSF, working with both monkeys and humans, have shown how rapid and radical such changes may be.

4. Despite categorical assertions by many that “congenital” phantoms cannot occur, there have been several reports (as Scatena has noted in a review of the subject) indicating that some people with aplasia — congenitally defective or absent limbs — do have phantoms. Klaus Poeck, in 1964, described an eleven-year-old girl born without forearms or hands who was able to “move” her phantom hands. As Poeck wrote, “In her first years at school, she had learned to solve simple arithmetic problems by counting with her fingers.… On these occasions she would place her phantom hands on the table and count the outstretched fingers one by one.”

It is not clear why some people born without limbs have phantoms and some do not. What is clear, as Funk, Shiffrar, and Brugger observed in one study, is that those who do have phantoms seem to have cerebral “action observation systems” similar to those of normally limbed people, allowing them to grasp action patterns by observing others and to internalize these as mobile phantoms. Those born without limbs who do not have phantoms, Funk et al. propose, may have problems in motion perception, especially judging the movements of other people’s limbs.

5. When Henry Head introduced the term “body image” (fifty or so years after Weir Mitchell had introduced the term “phantom limb”), he did not mean it to refer to a purely sensory image or map in the brain — he had in mind an image or model of agency and action, and it is this which needs to be embodied in an artificial limb.