 In ethics, a prima facie norm is an obligation (e.g., “prima facie, you should not hurt anybody”) which holds as long as exceptional circumstances (e.g., defending your own life) are absent (cf. Ross 1930 and the SEP-entry on moral reasoning). Dancy (2004, 17, 35f) uses the expression “pro tanto” instead of “prima facie”, which is standardly used in the current debate. Pietroski (1993) has promoted the ceteris paribus understanding of moral obligations as a solution to paradoxes of moral obligations. Especially for the solution of moral dilemmas, the cp-reading of moral obligations has proven to be helpful, because although two conflicting cp-obligations may block each other, they do not produce a strict consistency in the sense of deductive logic (see Horty 1994).