Puccetti confounds more or less countable brain parts with the functions they more or less subserve. Neonates whose left hemisphere is removed develop language and consciousness in the right hemisphere. Elderly people who suffer the same procedure generally do not. Despite Puccetti's claims, our moral intuitions about the latter are better served by Dennett's theory than by the alternative.
2. This is particularly apparent in Puccetti's treatment of Dennett's "parody." Dennett imagines the indeed "chilling" possibility that you -- a "full-fledged" conscious self -- are "trapped in the right hemisphere of a body... whose right side is now as remote as the body of a passing stranger... You would like to tell the world what it is like to be you, but you can't!" (p. 425). This is a chilling possibility and Dennett is at pains to show that research into the aftermath of commissurotomy does not support it; if such research did, it would suggest a very different moral evaluation of such surgery. Indeed, Dennett argues that one justification for his own theory is that it gives us good reason to dismiss this chilling possibility. But Puccetti's response is "Dennett's misconception here is based on the assumption that split-brain surgery necessarily implies splitting a single self into two." It is precisely that implication, however, that Dennett wishes to parody and dismiss; he in no way seeks to deny cognitive function to the right hemisphere.
3. Now Puccetti introduces his equally chilling countervision of the exquisitely conscious lifelong mute right brain, who has been aware since his earliest years that he cannot understand the babbling that goes on around him, except perhaps for hearing or contributing an occasional cuss word, and who is largely a pathetic slave of his left brain master. Real born-deaf mutes, of course, aren't this docile, and, given a halfway hospitable environment, develop language function and full-fledged consciousness and agency. In addition, it is well established that neonates who have left hemispherectomies develop language function and consciousness and appear perfectly normal except for a kind of grammar-blindness which only clearly comes out when the semantic and contextual clues with which they compensate are removed. But, of course, these individuals have had what the commissurotomized right brain, with its "few minutes of exclusive biography a week" (Dennett, p. 425) lacks, namely, the time to accrue "the sort of biography of which full-fledged selves are made." Puccetti's elderly left-hemispherectomized aphasic has the time but lacks the plasticity to make use of it. Indeed, far from justifying euthanasia for the left-hemisphere granny, as Puccetti ominously suggests, Dennett's theory serves our moral intuitions rather well. It is precisely because granny is not simply a right hemisphere but has a lovely face, body, and self, a center of narrative gravity now mainly dependent on the past and on others, such as her children, that we owe her respect and selfhood.
Dennett, D.C. (1991) Consciousness Explained. Boston: Little, Brown.
Puccetti, R. (1993) Dennett on the Split-Brain. PSYCOLOQUY 4(52) split-brain.1.