For human natural goodness, Foot gives the example of an anthropologist who made a promise to a Malayan native never to photograph him. Later he could get away with doing it, and the picture would have been valuable, but he had made a promise. Foot commented about this case that in giving a promise one makes use of a special kind of tool invented by humans for the better conduct of their lives, creating an obligation that (though not absolute) the harmlessness of its violation does not annul. Breaking the promise would have been defective. She thought there was a “natural-history story” to explain why the disposition to break a promise is defective, just as much as there is a natural-history story to explain why it is a defect not to be able to walk or see. She used Anscombe’s story about the need for the institution of promising if we are going to be able to get each other to do the sorts of things that constitute the human form of life.

RMH, in contrast, argued that promising creates an obligation in this way: if a speaker says sincerely that all promises are acts of placing oneself under (undertaking) an obligation to do the thing promised, he must himself be expressing his own subscription to the rule of the institution of promising and thus stating a moral principle. There is no deduction, therefore, from a fact to an obligation. It’s characteristic of words like “promise,” which have meaning only within institutions, that they can be introduced into language only when certain synthetic propositions about how we should act are assented to.

Foot thought there was a deduction of our obligation to keep our promises from our human form of life. Keeping our promises is an instance of justice, she thought, and she said that justice is one of the virtues that is an “Aristotelian necessity.” Foot was not an absolutist about keeping promises. Apart from killing the innocent, torture is the only absolute prohibition she mentioned. Torture was also an absolute prohibition for RMH, who spoke out of his own experience as a prisoner of the Japanese in WW2.

At any rate, Hare thinks Foot’s deduction doesn’t work. She treats our nature too much as a single unified package, and she was too optimistic in her account of practical rationality as sensitivity to the reasons this package gives us. Consider things like the fact that humans lie, cheat, or steal. Are these Aristotelian categoricals? Can we rule them out as irrelevant because they are not directly or indirectly related to our survival and reproduction? The accusation here is not that Foot was trying to deduce moral goodness from biology or from the inclinations we supposedly share with the hunter-gatherers who formed most of our evolutionary history. Other philosophers have tried to do this and failed.

For example, Arnhart argued that the good is the desirable (as in Aquinas) and the desirable is what is generally desired by human beings. By “generally desired” he meant that these desires are found in most people in every society throughout human history, and he thought evolution had given us these desires because they enhanced our chances of survival and reproduction. He listed twenty such desires, and his framework principle was that if a desire is general in this sense, belonging to this list, then its fulfillment is good. He did not find disinterested benevolence among these desires, and he concluded that it is merely utopian, beyond the order of nature, and foisted on us by religion.

Hare thinks it instructive to compare Arnhart with Foot on these points. Foot said that there is the same form of inference for humans and for wolves, from the Aristotelian categoricals about a form of life to conclusions about goodness. Unlike Arnhart she pointed out that Wittgenstein said at his end that he had had a wonderful life, but she said that he was not, in any ordinary sense, happy. Happiness is the human good only if we think of happiness in the way we discussed in relation to the letter-writers earlier, for whom it was already too late for happiness. But this kind of happiness is an ideal, and there is the same kind of difficulty as we found with RMH’s treatment of ideals. Foot had a worked-out theory about moral goodness in terms of natural facts and then had trouble integrating into it the distinction between the natural traits we should admire and the natural traits we should not. She included among Aristotelian categoricals seeking justice, but not the desire for power over others. This is better than Arnhart, but there’s a price. We know with Arnhart where his conclusions come from, even if we disagree with them. He faced the nasty as well as the nice aspects of our nature, and he was consistent about how we should live. In the same way Aristotle was. For Foot, by contrast, there was a gap. The categoricals for plants and non-human animals are supposed to be reached by saying how for a certain species nourishment was obtained, how development took place, what defenses were available, and how reproduction was secured. Answers to such questions for humans come in terms of deception and coercion, just as much as the recognition of rights. Foot was right to want a different way to think about the human good. But she did not give us a method for doing so that is “naturalistic” in the way the claim about the same “form of inference” from categoricals to virtues implies.

Hare thinks one basic problem is that the four natural ends given by Hursthouse don’t cohere, which means that our nature is not harmonious in the way she needs and claims. She wants to reject the view that human nature is “just a mess,” because she thinks this leads to moral nihilism and despair. But she does not consider the possibility that we are not exactly a mess, but a mixture of the kind Kant describes. This means that we are, as she denies, a “battleground.” There’s a dilemma here for her. Either the Aristotelian categoricals need to be already screened by ethical principle, in which case we get a deduction from nature only by this screening. Or we can allow that any typical feature leading to the four natural ends is a virtue, but then we will not get the deduction of a conclusion about moral goodness or the good human life. It’s better to allow that most of what we think constitutes a good human life comes from our ideals, which are not deducible from the four ends at all, though these ends are constraints on our ideals.

Another way to put the dilemma is that Hursthouse has two theses that conflict, when conjoined, with her admission that much of the work in deciding how to live does not come from the four ends, and that there is no fifth end characteristic of human animals from which to derive these decisions. These two theses are, first, what Hare calls “virtue dominance” and, second, deductivism about virtue. If the virtues are to be deducible from our nature, then they ought to give us a great deal more content about how to live than the admission that there is no fifth end implies.

We should concede that our nature puts a constraint on what we should say about a good human life and therefore about obligation. Foot and Hursthouse are right that it makes sense to talk about a human specific good, at least in ordinary speech, and so to talk about the kinds of human goodness that contribute to it. Even so, such facts don’t obligate us. Hare thinks the one exception is that we have a self-evident obligation to love God and neighbor, but none of the more specific obligations of the second table follow.

For DCT, it is God’s command that obligates. We should have the faith, though, that God wants our good, and commands us to live in a way that will be conducive to this end. So, even though obligations are not (with one exception) deducible from facts about human nature, those facts can serve as constraints on what we should believe about how God has commanded us to live. Does DCT derive an ought from an is? Hare thinks not, but defending his view is subtle. It’s true that God’s commanding something makes it obligatory, and that this is the right criterion (according to DCT) for the judgment that we ought to live a certain way. But we have to make what is the criterion our criterion, by a decision of the will.

Practical rationality can give us contradictory maxims, both of which fit the facts of human nature, unless we’ve rigged those facts by incorporating ideals into their specification. It’s not silly to be torn on occasion, even torn apart. When we bring the interests of others into the picture, especially the interests of those not related to us by friendship or family, most of us in the richer parts of the world fail most of the time. We simply do not think about the impact our own lifestyles have on those who are suffering in the rest of the world. Foot was herself not blind in this way, but she was too optimistic about the rest of us.

Hursthouse ends with the need for hope that we can flourish together, and not at each other’s expense, and she knows that this hope used to be called belief in (God’s) Providence. If we can’t rely on our nature to produce this ethical commonwealth, though, because our nature is a mixture of good and evil, then what is the ground of this hope? It must be something beyond our nature, and God’s sovereignty is an answer to be considered, as we did in the argument from providence in the first chapter.