Nicholas Agar argues, (1) that enhancement technologies could be used to create post-persons—beings of higher moral status than ordinary persons—and (2) that it would be wrong to create such beings.1 I am sympathetic to the first claim. However, I wish to take issue with the second.

Agar's second claim is grounded on the prediction that the creation of post-persons would, with at least moderate probability, harm those who remain mere persons. The harm that Agar has in mind here is a kind of meta-harm: the harm of being made more susceptible to being permissibly harmed—more liable to harm. Agar suggests that, if post-persons existed, mere persons could frequently be permissibly sacrificed in order to provide benefits to the post-persons. For instance, perhaps they could be permissibly used in lethal medical experiments designed to develop medical treatments for post-persons. By contrast, he suggests that mere persons typically cannot be permissibly sacrificed to provide benefits to other mere persons. He thus claims that mere persons would be more liable to sacrifice if post-persons existed than they are in the absence of post-persons. The creation of post-persons would make them worse off in at least this one respect.

Agar then argues that, since this meta-harm imposed on mere persons would not be compensated, it would be wrong to create post-persons. It is here that I believe his argument begins to go awry. According to the concept of compensation that Agar deploys (pp. 19 and 20), a harm imposed on X is compensated just in …