  Russ Shafer-Landau finds in Williams’ article the suggestion of a further argument, turning on the fairness constraint on appropriate blame (2003: 181–2). Blame is only appropriate if it is fair, and it is only fair to blame someone for their behavior if they had the capacity to act otherwise than they did. But an agent’s capacity to act is limited by her desires and dispositions, and therefore blame is only appropriate if an agent’s desires and dispositions gave her the capacity to act otherwise. This is a challenge for externalism because of the suggested connection between blame and reasons we discussed above: an agent is blameworthy for her action only if in so acting she failed to obey her  reasons.[1] It follows that an agent’s reasons must be limited by her desires and dispositions; some form of internalism is true.