Forthcoming in The Journal of Moral Philosophy M. Peterson, The Dimensions of Consequentialism: Ethics, Equality and Risk, (Cambridge: Cambridge University Press, 2013) 217 pages. ISBN: 9781107033030. Hardback: £55.00. Peterson's book contains several new and interesting ideas and arguments. He argues, in chapter 2, that rightness and wrongness come in degrees. In chapter 1, he introduces the idea of a moral aspect. As he defines it, "something counts as a moral aspect if and only if it directly influences an act's deontic status, irrespective of how other aspects are altered" (p. 3). I don't find this terribly illuminating, but, for our purposes, it will be sufficient to understand the notion as follows: some moral consideration X (e.g., equality or total wellbeing) counts as a moral aspect if and only if, for any act A, A must be optimal in terms of X if its performance is to be entirely right (i.e., neither wrong nor wrong to some degree). To understand this better, consider the choice depicted in Table 1. A3 is optimal (that is, most favorable) in terms of equality, for the two units of wellbeing that are available for distribution are distributed as equally as possible with one unit going to each of the two possible recipients. A1, by contrast, is the least favorable act in terms of equality. Here, all the wellbeing units go to Alice, and all the ill-being units go to Bob. A2 is nearly as favorable in terms of equality as A3, but it is, nevertheless, suboptimal, for the optimal distribution would be where each gets 999,998 units. So if equality is a moral aspect, then neither A1 nor A2 will be entirely right. Thus, if equality is the sole moral aspect, only A3 will be entirely right. But if total wellbeing is also a moral aspect, then no act will be entirely right. For none of the three alternatives are optimal in terms of both equality and total wellbeing. Table 1 Act Alice's Wellbeing Bob's Wellbeing A1 1,000,000 −100 A2 999,999 999,997 A3 1 1 The notion of a moral aspect allows Peterson to draw a distinction between two types of consequentialists: whereas one-dimensional consequentialists hold that there is a single moral aspect (such as total wellbeing), multidimensional consequentialists hold that there are two or more moral aspects (p. 3). This is an important distinction for Peterson, because his main aim is to argue that "the best version of consequentialism is multi-dimensional rather than one-dimensional" (pp. 2 and 14). He argues for this thesis in two parts. First, he argues, in chapters 3–5, that the multi-dimensional consequentialist should take at least equality, risk, and each individual's wellbeing to be moral aspects. Second, he argues in chapter 7 and throughout the book that such a multi-dimensional consequentialist theory accords better with our considered moral intuitions than even the best one-dimensional consequentialist theory does, where the best one-dimensional theory is, according to him, utilitarianism-the view that "an act's deontic status depends solely on the sum total of wellbeing it produces" (p. 139). These two parts are all that's Forthcoming in The Journal of Moral Philosophy needed to establish his thesis, for Peterson thinks that "we should take our considered moral intuitions seriously" and that "it is epistemically permissible to believe in a moral theory if and only if no other moral theory squares better with our considered moral intuitions" (p. 16). Unfortunately, I think that Peterson fails to establish this thesis. I'll explain why in a moment, but first I want to point out something curious about the thesis itself. The thesis is not that his version of multi-dimensional consequentialism (hereafter 'MDC') does better in accounting for our considered moral intuitions than non-consequentialist theories do, but only that MDC does better than other consequentialist theories do. Yet many people think that consequentialist theories do a terrible job of accounting for our considered moral intuitions. So those who agree with Peterson that the plausibility of a moral theory depends entirely on its ability to account for our considered moral intuitions and think that consequentialist theories are inferior in this respect will view Peterson's thesis as establishing only that MDC is the best of the worst. And that isn't all that interesting. But let's turn to Peterson's defense of the thesis. To see why I think that it fails, consider again the choice depicted in Table 1, and assume that Alice and Bob are equally deserving of wellbeing. My considered moral intuition is that A2 is entirely right. And this is what utilitarianism implies. MDC, by contrast, implies that A2 is somewhat wrong, for MDC is suboptimal both in terms of equality and in terms of Alice's wellbeing, each of which are moral aspects on MDC. Indeed, MDC implies that all three alternatives are somewhat wrong. So utilitarianism seems to do better in this case. But there may be other cases where MDC fairs better. In one such possible case, the choice is between A4 and A5, where A4 results in 74 units for Alice and 75 units for Bob and A5 results in 0 units for Alice and 150 units for Bob. Utilitarianism implies that A5 is obligatory, as it contains more total wellbeing. But, arguably, A4 is obligatory. Now, MDC avoids implying that A4 is obligatory. So that's a plus. But it doesn't imply that A4 is obligatory, and that's a minus. Instead, it implies that A4 is both right to a high degree and wrong to a low degree. Does this accord better with our considered moral intuitions? Not mine. For I don't have any intuitions about acts being somewhat right (that is, somewhat permissible) or somewhat wrong (that is, somewhat impermissible). (As Peterson uses the terms, 'right' is synonymous with 'permissible' and 'wrong' is synonymous with 'impermissible' (p. 193)). So if, unlike Peterson, we don't have intuitions about degrees of permissibility, it may seem like MDC won't be able to account for any of our intuitions. But I suspect that most of us do have intuitions about what someone who is morally motivated would rationally do, and MDC does have implications about this. (Here, the relevant sense of rationality isn't tied specifically to self-interest but is instead tied to fulfilling one's desires, including the desire to be a morally good agent.) Interestingly, Peterson rejects the view that morally motivated agents are rationally obliged to maximize rightness-that is, to do what "is right to a degree that is at least as high as that of every alternative" (p. 116). Instead, he thinks that morally motivated agents are rationally obliged (1) to perform acts that are entirely right, (2) to refrain from performing acts that are entirely wrong, and (3) "to randomise (i.e., [to] perform every alternative with some non-zero probability)" when faced with a choice between acts that are all somewhat right and Forthcoming in The Journal of Moral Philosophy somewhat wrong (p. 116). Thus, he believes that any act that is to any degree right "should be performed with some non-zero probability" (p. 117). Given the choice depicted in Table 1, then, A3 "should be performed with some non-zero probability. What does it mean to perform A3 with some non-zero probability? Peterson never says. So we might wonder whether A3 can be performed with some nonzero probability and yet not be performed. But I gather from what he says on p. 119 that what he means is that, if you face the choice depicted in Table 1, you should decide what to do using some mental process that has some (in this case, very small) chance of resulting in your performing A3. To my mind, that's absurd. I don't see why you should give any chance to performing A3. What's even more absurd is that MDC implies that you should perform A1 with some non-zero probability. After all, A1 is optimal in terms of Alice's well-being and, thus, somewhat right on MDC. And these implications seem much more absurd than anything utilitarianism implies. So I'm not convinced that MDC accords better with our considered moral intuitions than utilitarian does. (I also worry that we can't even do what MDC requires. Do we really have control over whether we perform an act with, say, 0.1 or 0.11 probability?) What's more, Peterson believes that, in terms of accounting for our considered moral intuitions, MDC not only does a better job than traditional, one-dimensional consequentialist theories such as utilitarianism, but also a better job than the nontraditional, one-dimensional consequentialist theories that consequentializers such as Jamie Dreier and myself have discussed. These consequentialist theories accommodate our intuitions about supererogatory acts, special obligations, agent-centered constraints, and much more. Unfortunately, Peterson dismisses such one-dimensional consequentialist theories for having "either produced (one-dimensional) ordinal rankings of acts, which can be shown to be unsatisfactory, or cardinal rankings based on technical assumptions that many non-consequentialists would reject," but he does so without showing that they do a poorer job of accounting for our considered moral intuitions, which, according to him, is all that matters in assessing the plausibility of a moral theory. Douglas W. Portmore Arizona State University douglas.portmore@asu.edu