This article deals with the understanding of human beings in the project of human enhancement. It shows that, in the voices of some representatives of the latter, there is a naturalistic tendency to reduce human beings either to their environment or to virtual reality. In such cases, the resulting entity would lack interiority as well as the first-person perspective. In this paper, it is argued that the possibilities opened up by biomedical sciences cannot release us from employing a multi-dimensional and integral concept of human beings wherein interiority plays an important role. The human enhancement project is not only a matter of technical feasibility; it also fundamentally concerns the essence of humanness. Hence the question of the nature of human beings and their condition is an indispensable part of this enterprise.