We have seen that there is no specifically "moral" sense of duty in Cicero, nor, as Anscombe pointed out, is there is a "moral ought" in Aristotle.
Irwin contests this in his contribution to the Kraut volume on NE, actually imputing voluntarism to Anscombe! And I'll say more about this later. But for now I want simply to point out something astonishing in "Modern Moral Philosophy", which I am not aware has been noticed.
Anscombe is discussing ways in which moral philosophers of her day, who reject the existence of a Divine Legislator, might nonetheless justify their appeal to a special, moral sense of 'ought', and she throws out the following idea:
There is another possibility here: "obligation" may be contractual. Just as we look at the law to find out what a man subject to it is required by it to do, so we look at a contract to find out what the man who has made it is required by it to do. Thinkers, admittedly remote from us, might have the idea of a foedus rerum, of the universe not as a legislator but as the embodiment of a contract. Then if you could find out what the contract was, you would learn your obligations under it. Now, you cannot be under a law unless it has been promulgated to you; and the thinkers who believed in "natural divine law" held that it was promulgated to every grown man in his knowledge of good and evil. Similarly you cannot be in a contract without having contracted, i.e. given signs of entering upon the contract. Just possibly, it might be argued that the use of language which one makes in the ordinary conduct of life amounts in some sense to giving the signs of entering into various contracts. If anyone had this theory, we should want to see it worked out. I suspect that it would be largely formal; it might be possible to construct a system embodying the law (whose status might be compared to that of "laws"of logic): "what's sauce for the goose is sauce for the gander," but hardly one descending to such particularities as the prohibition on murder or sodomy. Also, while it is clear that you can be subject to a law that you do not acknowledge and have not thought of as law, it does not seem reasonable to say that you can enter upon a contract without knowing that you are doing so; such ignorance is usually held to be destructive of the nature of a contract.I would guess these remarks were inspired by the argument of Grice's "Meaning", published in 1957, the year before the appearance of Anscombe's essay. But has anyone noticed that Anscombe here, in a few words, anticipates the "discourse ethics" of Habermas and Apel?--anticipating, too, the shortcomings in this approach.