Recognizing fallacies in deontological arguments

Deontological arguments are those involving rules that refer to properties of actions other than their consequences, e.g., vaccination, act vs.\ omission. These arguments are often used to justify public policies. In principle, some of them could make outcomes worse than the outcomes of utilitarian choices, i.e., choices designed to yield the best expected consequences. Arguments for deontological choices ought to explain why it is better to make outcomes worse. We suggest that political arguments attempting to do this are usually fallacious. We list several categories of fallacies. We report two demonstrations in which we ask whether people without special training can classify fallacies correctly. People seem generally weak at this task, although those who are more inclined to accept the standards of actively open-minded thinking (AOT) do better, possibly because both AOT and fallacy classification require meta-cognitive competence. Performance may also be improved by a brief instructional intervention. The idea of requesting justification for making things worse is a new method for empirical research on moral judgment, a device for philosophical argument, and possibly an approach to instruction.