2012 年 30 巻 p. 20-29
In this paper, I argue against a recent movement that advocates the enhancement of human character. It holds that character enhancement is a kind of rational self-manipulation, so there is no ethical wrongness in enhancing our character. It also says that many conventional arguments against enhancement (e.g. by US President's Council on Bioethics) rely on a conservative misunderstanding of the nature of enhancement technology. However, in my view, advocators of enhancement fail to capture the elements of the arguments of opponents of enhancement from three perspectives: (1) richness of life, (2) authenticity, and (3) mastery. First, advocators of enhancement hold that character enhancement does not decrease the richness of our life, but it can increase the possibility of living an enriched life. But their conception of the richness is shallow and very limited. The original concept of richness of our life that is intended by opponents of enhancement is deeper, wider and something that is impossible to put into words. Second, advocators of enhancement hold that it is no use arguing whether a certain character is authentic, because character changes naturally and gradually. So the point is whether one can admit the character as one's own. But the concept of authenticity that is used in the context of character enhancement need not be a literal authenticity, but it is a kind of "thick" concept that includes description and evaluation, and is conventionally defined by community. Third, advocators of enhancement hold that character enhancement is not an instance of the drive for mastery because it is only a rational self-manipulation, so it should be seen as a kind of conduct of self-decision. But character enhancement that includes changing the future self cannot be regarded as a selfdecision.