Prima facie duties are those duties social workers ought to perform, other things being equal. A principal challenge in social work, however, is that “other things” often are not equal. Moral philosophers refer to this as the ceteris paribus problem; ceteris paribus is Latin for “other things being equal.” Ross’s prescient conceptual framework anticipated these kinds of difficult moral choices faced by today’s social workers. Using Ross’s language, among the most daunting challenges social workers face is choosing their actual duty from among competing prima facie duties.