Some of our moral commitments strike us as necessary, and this feature of moral phenomenology is sometimes viewed as incompatible with sentimentalism, since sentimentalism holds that our commitments depend, in some way, on sentiment. His dependence, or contingency, is what seems incompatible with necessity. In response to this sentimentalists hold that the commitments are psychologically necessary. However, little has been done to explore this kind of necessity. In this essay I discuss psychological necessity, and how the phenomenon of imaginative resistance (...) offers some evidence that we regard our moral commitments as necessary, but in a way compatible with viewing them as dependent on desires (in some way). A limited strategy for defending sentimentalism against a common criticism is also offered. (shrink)