A claim about continuing technological progress plays an essential, if unacknowledged, role in the philosophical literature on “human enhancement.” I argue that—should it eventuate—continuous improvement in enhancement technologies may prove more bane than benefit. A rapid increase in the power of available enhancements would mean that each cohort of enhanced individuals will find itself in danger of being outcompeted by the next in competition for important social goods—a situation I characterize as an “enhanced rat race.” Rather than risk the chance (...) of being rendered technologically and socially obsolete by the time one is in one’s early 20s, it may be rational to prefer that a wide range of enhancements that would generate positional disadvantages that outweigh their absolute advantages be prohibited altogether. The danger of an enhanced rat race therefore constitutes a novel argument in favor of abandoning the pursuit of certain sorts of enhancements. (shrink)