Liberal eugenics, human enhancement and the concept of the normal

In this chapter, I examine the uses to which the concept of the normal is put in debates on liberal eugenics and human enhancement. I discuss three particular approaches to human nature and the normal: Jurgen Habermas s emphasis on human nature as a normative concept that grounds the moral distinction between therapy and enhancement; the use of the normal species function model of normality by Allen Buchanan and his co-authors; and finally, John Harris s rejection of normality and consequent embrace of enhancement technologies. Following this, I draw on the work of Georges Canguilhem to outline a conception of the normal that would avoid the worries that hound Habermas s normative account of human nature, while still allowing for a distinction between therapy and enhancement.