As Sacks has already discussed, the neurologist’s favorite word is “deficit”; however, the concept of superabundance is so rare in neurology that there’s no convenient word for it. Modern neurology is ill-equipped to discuss “monstrosities or manias.” For instance, the great neurologist Hughlings Jackson wrote about some “hyper-psychological states,” but only rarely.
Once again, Sacks discusses a paradigm that neurologists use to conceive of different neurological disorders. It’s crucial to notice that the paradigm of superabundance is no more or less “correct” than the paradigm of deficit; both are useful insofar as they help doctors better understand the mind. Sacks’s point seems to be that we need many different, competing paradigms for neurological disorders.
In the second part of the book, Sacks will examine cases of patients who suffer from disorders that cause an excess of a brain function. When compared with disorders that cause deficits in a brain function, these cases will be more overtly focused on what the patients do, not just what they’re missing. Thus in studying excess, Sacks says we’re forced to talk about “neurology of action.” Traditional neurology is excessively focused on the brain’s mechanical processes and not enough on the effects of such processes on a patient’s life.
Perhaps as a consequence of relying too heavily on the paradigm of deficit, neurologists don’t focus on action as thoroughly as they should (since, by definition, the notion of a deficit emphasizes the absence of behavior far more than it suggests a different behavior). Moreover, Sacks will endeavor to talk about patients’ lives and personalities instead of analyzing their disorders in overly mechanical, left-brained terms.
In this section, Sacks will also discuss some cases in which an illness initially presents as “a wonderful feeling of health and well-being.” Sacks has always been fascinated by such a concept, and wrote about it in his earlier book, Awakenings. Sometimes patients sense that, in spite of their health, they’re possessed by their own disease, or even that they’re headed for “disaster.”
Sacks will also discuss the concept of a neurological “disorder” being beneficial in some way, although, for the time being, he will restrict himself to disorders that have both overt advantages and disadvantages.