Kant's fact of reason as source of normativity

In _The Sources of Normativity_, Christine M. Korsgaard argues that unconditional obligation can be accounted for in terms of practical identity. My argument in this paper is that practical identity cannot play this foundational role. More specifically, I interpret Korsgaard's argument as beginning with something analogous to Kant's fact of reason, viz. with the fact that our minds are reflective. I then try to show that her determination of this fact is inadequate and that this causes the argument concerning practical identity to fail. Finally, I argue that a conception of the fact of reason more in line with what I take to be Kant's own is necessary to account for unconditional obligation.