The tendency to ignore or sometimes even to deny that one's left arm or leg is paralyzed was termed anosognosia, ("unaware of illness") by the French neurologist Francois Babinski, who first observed it clinically in 1908. In anosognosia, the patient is unaware of or denies a paralyzed limb, and in hemianosognosia, the patient behaves as if half the body were nonexistent. The "counterfeit" limb is a milder version of anosognosia, where the limb seems less than real. Oliver Sachs describes how his paralyzed leg had "vanished, taking its place with it...The leg had vanished taking its 'past' away with it. I could no longer remember having a leg." (See Oliver Sachs, A Leg to Stand On, New York, 1984,)
Anosognosia appears to occur as the result of a lesion to the right hemisphere of the brain, causing paralysis on the left side of the body, but not vice-versa. V.S Ramachandran theorizes that the left hemisphere constucts coherent stories and belief systems that are not subject to reexamination every time there is a discrepancy. But when the discrepencies are too great, the right hemisphere insists on revision. (this ressembles Kuhn's descriptions of paradigmshifts.) If the right hemisphere is damaged, the left hemisphere will go right on ignoring the very fact of the paralysis. (see brain: hemispheric specialization)
the phantom limb and anosognosia indicate that our experiences are organized not by real objects and relations but by the expectations and meanings objects have for the body's movement and capacities. That the performance requirements of the body are primary is evidenced by the fact that amputated animals immediately develop new gaits that take place correctly on the first try. When humans loose their dominant hand, they can take over complicated performance such as writing with striking speed with their other hand or any movable member. For Kurt Goldstein, this is evidence of functional patterns that are independent of a specific apparatus.
A milder, but related, disorder of the visual field is agnosia. Agnosia was one of the primary asymbolias or impairments of a hypothetical symbolic function. (See J. Crary, Suspensions of Perception, pp 94-95) Essentially, it is described as a purely visual awareness of an object, that is, an inability to make any symbolic or conceptual identification of an object. In Kurt Goldstein's later clinical work in the 1920's, agnosia was a state in which the objects within a perceptual field ceased to be integrated into a practical or pragmatic plasticity, ceased to have intentional or lived coordinates. (The Organism, pp 196-198) Goldstein's cousin, the philosoper Ernst Cassirer, was to characterize agnosia as a disturbance of "the representative function of perception. The perception remains flat, as it were; it is no longer determined and directed toward a dimension of depth, an object." )The Philosophy of Symbolic Forms, vol 3. p. 239) (cf "waning of affect.)