What if brain in vitro (in above example) could not communicate with us at all? Would we still think it is possessed of a self? The biological functions of people in coma are maintained. But do they have an identity, a self? If yes, why do we "pull plug" on them so often?

It would seem (as it did to Locke) that we accept that someone has a self-identity if: (a) He has same hardware as we do (notably, a brain) and (b) He communicates his humanly recognizable and comprehensible inner world to us and manipulates his environment. We accept that he has a given (i.e., same continuous) self-identity if (c) He shows consistent intentional (i.e., willed) patterns ("memory") in doing (b) for a long period of time.

It seems that we accept that we have a self-identity (i.e., we are self-conscious) if (a) We discern (usually through introspection) long term consistent intentional (i.e., willed) patterns ("memory") in our manipulation ("relating to") of our environment and (b) Others accept that we have a self-identity (Herbert Mead, Feuerbach).

Dan (probably) has same hardware as we do (a brain). He communicates his (humanly recognizable and comprehensible) inner world to us (which is how he manipulates us and his environment). Thus, Dan clearly has a self-identity. But he is inconsistent. His intentional (willed) patterns, his memory, are incompatible with those demonstrated by Dan before accident. Though he clearly is possessed of a self-identity, we cannot say that he has SAME self-identity he possessed before crash. In other words, we cannot say that he, indeed, is Dan.

Dan himself does not feel that he has a self-identity at all. He discerns intentional (willed) patterns in his manipulation of his environment but, due to his amnesia, he cannot tell if these are consistent, or long term. In other words, Dan has no memory. Moreover, others do not accept him as Dan (or have their doubts) because they have no memory of Dan as he is now.

Interim conclusion:

Having a memory is a necessary and sufficient condition for possessing a self-identity.

III. Repression

Yet, resorting to memory to define identity may appear to be a circular (even tautological) argument. When we postulate memory - don't we already presuppose existence of a "remembering agent" with an established self-identity?

Moreover, we keep talking about "discerning", "intentional", or "willed" patterns. But isn't a big part of our self (in form of unconscious, full of repressed memories) unavailable to us? Don't we develop defence mechanisms against repressed memories and fantasies, against unconscious content incongruent with our self-image? Even worse, this hidden, inaccessible, dynamically active part of our self is thought responsible for our recurrent discernible patterns of behaviour. The phenomenon of posthypnotic suggestion seems to indicate that this may be case. The existence of a self-identity is, therefore, determined through introspection (by oneself) and observation (by others) of merely conscious part of self.

Sam Vaknin is the author of Malignant Self Love - Narcissism Revisited and After the Rain - How the West Lost the East. He is a columnist for Central Europe Review, PopMatters, and eBookWeb , a United Press International (UPI) Senior Business Correspondent, and the editor of mental health and Central East Europe categories in The Open Directory Bellaonline, and Suite101 .

Visit Sam's Web site at http://samvak.tripod.com

At this early stage, patient is unable to differentiate his own feelings and needs from those of others. His cognitive and perceptual distortions and deficits (for instance, regarding his body image – known as a somatoform disorder) only increase his feeling of personal ineffectualness and his need to exercise even more self-control (by way of his diet).

The patient does not trust himself in slightest. He rightly considers himself to be his worst enemy, a mortal adversary. Therefore, any effort to collaborate with patient against his own disorder is perceived by patient as self-destructive. The patient is emotionally invested in his disorder - his vestigial mode of self-control.

The patient views world in terms of black and white, of absolutes ("splitting"). Thus, he cannot let go even to a very small degree. He is constantly anxious. This is why he finds it impossible to form relationships: he mistrusts (himself and by extension others), he does not want to become an adult, he does not enjoy sex or love (which both entail a modicum of loss of control).

All this leads to a chronic absence of self-esteem. These patients like their disorder. Their eating disorder is their only achievement. Otherwise they are ashamed of themselves and disgusted by their shortcomings (expressed through distaste with which they hold their body).

Eating disorders are amenable to treatment, though comorbidity with a personality disorder presages a poorer prognosis. The patient should be referred to talk therapy, medication, and enrol in online and offline support groups (such as Overeaters Anonymous).

Recovery prognosis is good after 2 years of treatment and support. The family must be heavily involved in therapeutic process. Family dynamics usually contribute to development of such disorders.

In short: medication, cognitive or behavioural therapy, psychodynamic therapy and family therapy ought to do it.

The change in patient following a successful course of treatment is VERY MARKED. His major depression disappears together with his sleeping disorders. He becomes socially active again and gets a life. His personality disorder might make it difficult for him – but, in isolation, without exacerbating circumstances of his other disorders, he finds it much easier to cope with.

Patients with eating disorders may be in mortal danger. Their behaviour is ruining their bodies relentlessly and inexorably. They might attempt suicide. They might do drugs. It is only a question of time. The therapist's goal is to buy them that time. The older they get, more experienced they become, more their body chemistry changes with age – better their chances to survive and thrive.

Sam Vaknin is the author of Malignant Self Love - Narcissism Revisited and After the Rain - How the West Lost the East. He is a columnist for Central Europe Review, PopMatters, and eBookWeb , a United Press International (UPI) Senior Business Correspondent, and the editor of mental health and Central East Europe categories in The Open Directory Bellaonline, and Suite101 .

Visit Sam's Web site at http://samvak.tripod.com