  Both types of perfectionism confront formidable challenges. Proponents of human nature perfectionism must present an adequate account of human nature. More precisely, they must give a plausible account of the properties that are central to human nature and the development of which explain why certain activities and states are good for human beings (Hurka 1993). Whether there is any account of human nature that both yields plausible results and has genuine explanatory power can be doubted (Dorsey 2010). By contrast, proponents of objective goods perfectionism, having freed the identification of objective goods from dependence on the development of human nature, must explain why some things, and not others, are counted as good. Objective goods perfectionists need not formulate an exhaustive list of these goods. They may think such an undertaking to be misguided. But they should have something to say about what makes an alleged good an objective good, one worthy of pursuit (Sumner 1996, Sher 1997).