In The Sources of Normativity, Christine Korsgaard affirms that Enlightenment morality is true: humanity is valuable. To many of us few claims seem more obvious. Yet Enlightenment thinkers such as Kant do not limit themselves to affirming that humanity is valuable. They appeal to reason in an effort to establish it. They try to show that, in some sense, we are rationally compelled to recognize the value of humanity. Korsgaard joins in this effort. She champions the claim that unless we (...) take humanity to be valuable, we condemn ourselves to complete practical skepticism, i.e., to the view that we have no reason to do anything at all.Korsgaard discusses two arguments that, she believes, support this claim. The first she attributes directly to Kant in a series of influential papers on his ethics. The second argument, which she calls a ‘fancy new model’ of the first, she constructs under her own name in The Sources of Normativity. I will defend the view that neither of these arguments succeeds. In doing so, I will not be trying to show that we are mistaken in believing humanity to be valuable. (shrink)