Abstract
There has been a lack of precision in attempts to say precisely what it might mean to be or become posthuman. This article offers a way to determine what distinguishes humans from posthumans. It treats the relationship between humans and posthumans as the mirror image of the relationship between humans and prehumans. I propose that we view posthumans as not us, but of us. Posthumans are distinct from humans but of humans, where the “of” expresses an important evaluative relationship. This account furnishes a framework for considering the proposals of some transhumanist philosophers that we should forsake our humanity in favor of superior posthuman modes of existence. I argue that we have a pro tanto commitment to remaining human. There are costs in surrendering our humanity that could be justified, but only if the potential benefits from becoming posthuman were both great and probable. Transhumanists offer effective marketing for radical enhancement. But there is a gap between a marketing pitch for radical enhancement and one that justifies surrendering the real benefits of remaining human.