Abstract
Many significant moral theories, ones to which a large number of philosophers pledge themselves, employ in a fundamental way the criterion of universalizability. This is true not only of Kant and his more illustrious successors, but also utilitarians of many sorts. But concomitant with adherence to universalizability as a moral criterion is adherence to the belief that certain features of putatively moral acts and immoral acts are relevant and others irrelevant to the determination to the rightness or wrongness of those acts. Despite the fact that this belief is problematic, few moral philosophers have openly struggled with the problem of relevant descriptions. It is as if investigation of this problem would invite unsettlable doubts about universalizability itself.