Human enhancement and supra-personal moral status

Several authors have speculated that (1) the pharmaceutical, genetic or other technological enhancement of human mental capacities could result in the creation of beings with greater moral status than persons, and (2) the creation of such beings would harm ordinary, unenhanced humans, perhaps by reducing their immunity to permissible harm. These claims have been taken to ground moral objections to the unrestrained pursuit of human enhancement. In recent work, Allen Buchanan responds to these objections by questioning both (1) and (2). I argue that Buchanan's response fails. However, I then outline an alternative response. This response starts from the thought that, though moral status-increasing human enhancements might render ordinary, unenhanced humans less immune to permissible harm, they need not worsen the overall distribution of this immunity across beings. In the course of the argument I explore the relation between mental capacity and moral status and between moral status and immunity to permissible harm.