 Stern (2017) explains this argument as follows. To act is to do or choose something for a reason. However, an agent has reasons to act only because of her practical identity; she does not have reasons to act independently of that identity. But a practical identity can yield such a reason only if she regards that identity as valuable. Merely being a parent gives one no reason to care for one’s children. Rather, valuing one’s parenthood has this force. At the same time, an agent cannot regard a particular practical identity as valuable in itself; Korsgaard argues that this sort of realism about value is implausible. The only remaining explanation is that she regards it as valuable because of the contribution it makes to providing her with reasons and values by which to live. But then she must believe that it matters that her life has the sort of rational structure that having such identities provides. However, to see that as mattering, she must regard leading a rationally structured life as valuable. Then, in conclusion, to regard leading such a life as valuable, an agent must see her rational nature as valuable.