In "Internal and External Reasons' Bernard Williams suggests that internalism about reasons is compatible with the idea that beliefs can motivate; that is, that internalism is compatible with cognitivism about motivation. However, contrary to Williams' suggestion, I will argue that internalists about reasons are in fact committed to Humeanism about motivation; that is, that internalists about reasons cannot allow that beliefs can motivate in their own right. Since I believe that Humeanism about motivation is false, I think internalism about reasons implies something false, and that therefore internalism about reasons should be rejected. In this essay I shall say nothing about why I think Humeanism is false; rather, my aim will be to establish that internalism about reasons is compatible only with (or makes sense only on) a Humean theory of motivation. To do this, I will try to show that cognitive motivational internalism (CMI) is, at best, an unstable position.