Sir David Ross introduced and discussed his notion of prima facie duties in chapter 2 of The Right and the Good , and it is to this chapter that I shall devote most attention. I wish to show that the distinction between prima facie and “actual” duties, as expounded by Ross, entails that there are no “actual” duties; and I wish to show that this unfortunate consequence of the distinction arises from Ross's explicit epist-emological views. Writers such as Ewing, Baier (...) and Frankena, who have quoted Ross's distinction with some degree of approval, force one to ask how, precisely, they interpreted it. In the first part of this paper I set out Ross's exposition in detail, since failure to do this has blinded adherents to its difficulties; in the second part I summarise my findings and indicate the problems Ross rightly poses for us; in the third part I suggest possible sources for Ross's views. Two points should be noted at the outset. Firstly, the distinction applies to acts, not actions; “act” refers to “the thing done, the initiation of change, and ‘action’ the doing of it, the initiating of change, from a certain motive” . Secondly, the term “right” is used throughout as synonymous with “what is my duty”. (shrink)