This chapter reviews the state of the ongoing debate between dystopic and liberal posthumanists on enhancement technologies, with a closer look at the explicit and implicit arguments advanced by each regarding some specific technologies like preimplantation genetic diagnosis, the use of psychopharmaceuticals for mood and cognitive enhancement, and genetic engineering. In broad terms, dystopic posthumanism subscribes to the moral claim that human enhancement is intrinsically wrong, and the political claim that it should be banned or restricted. Liberal posthumanism, conversely, holds that enhancement is neither intrinsically wrong nor unusually dangerous, and should generally be permitted. On both sides, the arguments that support these claims abound, and can be grouped into three categories: social, technical and methodological arguments.
Beyond these relatively commensurable terms, however, the debate between dystopic and liberal posthumanism is an ethical dispute at the core of which lie incommensurable views of human nature. While this is more obvious in the case of the dystopic posthumanist critique, which proceeds from the idea that technological intervention for enhancement purposes poses a threat to human nature, it is also the case that liberal posthumanism invokes human nature in its support of enhancement. Only, rather than extolling human nature as a fixed, stable and ‘given’ essence, it draws on a conception of the human as an evolving, dynamic and imperfect organism, who, by nature, aspires towards self-improvement.