Limited Conventions about Morals

In this thesis I describe how conventions specify how to put normative principles into practice. I identify a class of recurring situations where there are some given normative principles in effect, but they underdetermine what each individual should do, and what is best for an individual depends on what others do. I demonstrate that in such cases, whenever the community develops a response that repeatedly brings them to as good an outcome as is available according to their principles, that response is a Lewisian convention where the benefit of an outcome to each individual is measured by the extent to which it conforms to the principles they subscribe to. Since these conventions are constrained by the normative principles, I call them limited conventions. They are supplements to the principles, and are ineradicably involved in moral action insofar as the abovementioned cases of moral underdetermination are in play. That has the consequence that in these cases the only reliable way to follow your principles is to follow the relevant conventions. As examples of this mechanism I offer a conventionalist analysis of authority, such that the commands of an authority is normative when they instantiate a limited convention, and of the variation in understandings of virtue and vice across societies, such that the evaluative vocabulary of each society is a set of different limited conventions about how to express in word and deed the evaluative points of the virtues and vices in question. Finally, I discuss how conventions and similar forms of guidance provide a way for individuals to participate in their community’s moral life without having a full understanding of the principles that underlie it, or even if they are profoundly ignorant or outright mistaken about the demands of morality.