Through an analysis of the appeals to human dignity used by bioconservatives to criticize transhumanist proposals for aggressive development of human enhancement technologies, I identify an implicit tension within such appeals that renders them internally incoherent and ultimately unpersuasive. However, I point the way to a more compelling objection to radical human enhancement available to bioconservatives, a version of the argument from hubris that employs an Aristotelian account of prudential virtue in order to challenge the normative content of the liberal transhumanist vision. The vulnerability of the transhumanist project to this argument is underscored by Ortega y Gasset’s critique of technological mass culture, in which he suggests that humans may increasingly lack the prudential virtues needed to identify and authentically choose those ends worthy of technological pursuit.