The human enhancement debate typically centres on moral issues regarding changes in human nature, not on the means for these changes. We argue that one cannot grasp what is morally salient about human enhancement without understanding how technologies affect human action and practical reasoning. We present a minimalist conception of human agents as bounded practical reasoners. Then, we categorise different effects of technologies on our possibilities for action and our evaluation of these possibilities. For each, we discuss whether enhancement technologies have morally salient effects; which technologies show these effects; and whether these differ significantly from those of other, non-enhancement technologies. We conclude that enhancement technologies are morally salient in several respects, that not all enhancement technologies share all those morally salient respects, and that continuities with traditional technologies may be found in all morally salient respects.