I PROMISES AND NORMATIVE POWERS

Making a promise makes a normative difference. What difference does it make and how does it make it? I regard promissory obligations as upshots of the exercise of “normative powers,” powers to create or rescind practical requirements at will. Specifically, as Joseph Raz says, “To promise is … to communicate an intention to undertake by the very act of communication an obligation to perform a certain action.” (Raz calls obligations created in this way “voluntary obligations.”) In this manner, you establish a new normative relationship with others by, among other things, transferring authority to others to hold you to a particular performance. The result is a voluntary restriction of the range of actions you would otherwise be entitled to perform.

This transaction affects what you have reason to do. Some of the reasons that promising creates are “content-independent,” as Raz puts it; they depend in part on how they came to be, rather than on the independent desirability of the performance in question. (This is characteristic of all reasons of authority.) Your reason to return the book to me by Friday, for example, is primarily that you “engaged” with me to return it by then, quite apart from the quite different consideration that I might be in need of the book then (a reason you might well have to return the book to someone to whom you don't owe it).