The Subjective Moral Duty to Inform Oneself before Acting

The requirement that moral theories be usable for making decisions runs afoul of the fact that decision makers often lack sufficient information about their options to derive any accurate prescriptions from the standard theories. Many theorists attempt to solve this problem by adopting subjective moral theories—ones that ground obligations on the agent’s beliefs about the features of her options, rather than on the options’ actual features. I argue that subjective deontological theories (such as Prichard’s and Ross’s) suffer a fatal flaw, since they cannot appropriately require agents to gather information before acting.