Alien Hand/Limb Syndrome
“The alien hand syndrome, as originally defined, was used to describe cases involving anterior corpus callosal lesions producing involuntary movement and a concomitant inability to distinguish the affected hand from an examiner’s hand when these were placed in the patient’s unaffected hand. In recent years, acceptable usage of the term has broadened considerably, and has been defined as involuntary movement occurring in the context of feelings of estrangement from or personification of the affected limb or its movements. Three varieties of alien hand syndrome have been reported, involving lesions of the corpus callosum alone, the corpus callosum plus dominant medial frontal cortex, and posterior cortical/subcortical areas. A patient with posterior alien hand syndrome of vascular aetiology is reported and the findings are discussed in the light of a conceptualisation of posterior alien hand syndrome as a disorder which may be less associated with specific focal neuropathology than are its callosal and callosal-frontal counterparts.” – http://jnnp.bmj.com/content/68/1/83.full
This kind of alienation from the function of a limb would seem to contradict functionalism. If functionalism identifies consciousness with function, then it would seem problematic that a functioning limb could be seen as estranged from the personal awareness, is it is really no different from a zombie in which the substitution level is set at the body level. There is no damage to the arm, no difference between one arm and another, and yet, its is felt to be outside of one’s control and its sensations are felt not to be your sensations.
This would be precisely the kind of estrangement that I would expect to encounter during a gradual replacement of the brain with any inorganic substitute. At the level at which food becomes non-food, so too would the brain become non-brain, and any animation of the nervous system would fail to be incorporated into personal awareness. The living brain could still learn to use the prosthetic, and ultimately imbue it with its own articulation and familiarity to a surprising extent, but it is a one way street and the prosthetic has no capacity to find the personal awareness and merge with it.