 Oaths and vows partially fill out what I call the “breadth criterion”: Theories of promising should cover not only customary, interpersonal promises but also sibling phenomena, including oaths and vows. Promises, oaths, and vows are all forms of voluntary binding commitments; indeed, the terms are often used interchangeably. They should be taken up into theory together. The familiar and powerful grounds for this intuitive idea are at least twofold: It is more parsimonious to have a single theory that covers the entire family rather than developing distinct theories for each of the phenomena, and if there is such a theory, its explanatory power will compare favorably to theories that fail to cover some of the phenomena in question. A theory of promising that is silent about oaths and vows is one we have less reason to accept than one that can illuminate the capacity of oaths and vows to produce moral obligations. Provisionally at least, the breadth criterion should be applied to competing theories of promising. (Fruh 2019: 859)