Moral responsibility: from function to fittingness?

Theorists of moral responsibility have suggested that some of our responsibility-responses have a 'point', or a 'function', and that when, in general, blame with respect to a certain kind of person could not fulfill its function, that kind of person is not in fact blameworthy. Recently, however, some theorists (Beglin 2018, De Mesel 2025) seem to suggest a stronger thesis: if blame with respect to some kind of person can fulfill its function, then such persons are indeed blameworthy. Beglin and De Mesel thus seek to put pressure on traditional incompatibilism, on grounds that blame has a function that can be fulfilled, even if no one ever has libertarian free will. In this paper, I argue that this style of argument cannot succeed: once we distinguish between 'internal' and 'external' function, we can see that the core argument faces a dilemma. If the proposal is one about 'external' function, we cannot move 'from function to fittingness'; whereas if the proposal is about 'internal' function, the incompatibilist will reject that proposal on the usual grounds.