Alasdair MacIntyre has famously observed that in our historical moment all moral arguments are interminable. It is not just that the wide range of debates seems to have unlimited endurance and runs on without end but that there seems to be no rational way of actually achieving moral agreement. Each argument arrives at conclusions through logically valid reasoning, but at the source of these argu- ments are rival premises, conceptual starting points that imply competing normative claims or evaluations. As MacIntyre puts it, “From our rival conclusions we can argue back to our rival premises; but when we do arrive at our premises argument ceases and the invocation of one premise against another becomes a matter of pure assertion and counter-assertion.” Premises can never be rationally established and, therefore, it is impossible to evaluate rationally the claims of one position against another. The incommensurability of moral arguments necessarily means that they are interminable.