In a brief passage in the first two editions of his Inquiry, Hutcheson gives an argument that has been little noticed in the literature, against the view that what motivates us to act morally is the prospect of taking pleasure in our evaluation of ourselves as moral. I reconstruct Hutcheson's argument and show how it differs from a similar argument from Butler and Hume. I also show that Hutcheson's argument is inconsistent with another important view of his. In the third and fourth editions of the Inquiry, Hutcheson omits the argument. I speculate that the reason for this was that he became aware that his argument was inconsistent with that other view of his.
Avraham Sommer (Sun,) studied this question.