Does the Incommensurability of Prudential and Impartial rationality avoid the dualism of Practical Reason?

Editor’s note: This article was originally posted at MandM. It has been posted here with permission of author.

I have been discussing the dualism of practical reason. As I understand it, this is an inference from three premises:

[1] We always have most reason to do what is morally required
[2] An act is morally required if and only if it is impartially demanded: demanded by rules justified from a perspective of impartial benevolence.
[3] If there are cases where, what is impartially demanded of a person, is an action contrary to their long-term self-interest, then the strongest reasons do not always favour what is impartially demanded.

The conclusion: unless we assume that requirements of self-interest never substantially conflict with impartial demands, we can only coherently affirm [1] and [2]. Seeing [1] is a plausible thesis about the authority of requirements, and [2] is a plausible thesis about their content. Our fundamental moral intuitions about morality cannot be reconciled.

One response to this argument is to deny [3]. This involves contending that impartial requirements are overriding: If impartial and prudential requirements clash, the former always take precedence. In my last post, I mentioned an argument made by Stephen Layman against this contention. Layman asks us to consider the case of Ms Poore;

Ms. Poore has lived many years in grinding poverty. She is not starving, but has only the bare necessities. She has tried very hard to get ahead by hard work, but nothing has come of her efforts. An opportunity to steal a large sum of money arises. If Ms. Poore steals the money and invests it wisely, she can obtain many desirable things her poverty has denied her: cure for a painful (but nonfatal) medical condition, a well-balanced diet, decent housing, adequate heat in the winter, health insurance, new career opportunities through education, etc. Moreover, if she steals the money, her chances of being caught are very low, and she knows this. She is also aware that the person who owns the money is very wealthy and will not be greatly harmed by the theft. Let us add that Ms. Poore rationally believes that if she fails to steal the money, she will likely live in poverty for the remainder of her life. In short, Ms. Poore faces the choice of stealing the money or living in grinding poverty the rest of her life. In such a case, I think it would be morally wrong for Ms. Poore to steal the money; and yet, assuming there is no God and no life after death, failing to steal the money will likely deny her a large measure of personal fulfillment, i.e., a large measure of what is in her long-term best interests[1].

Layman takes this case to illustrate that impartial requirements are not overriding. If there are cases where impartial demands require us to make a great sacrifice that confers relatively modest benefits on others, the strongest reasons do not support complying with impartial demands.[2]

Peter Bryne has criticised Layman’s example. He writes:

Layman’s way of approaching his moral argument suggests the following picture: rational agents are aware of a variety of reasons for action. They see prudential reasons vying with moral reasons. They measure whether moral reasons for doing something outweigh prudential reasons for not doing it, and they follow that set of reasons which is stronger overall. Now it is time to ask the question “From what standpoint does Layman’s rational agent weigh or measure reasons for action?[3]

Bryne thinks this is question raises an important challenge:

The unclarity in the language of weighing reasons for action, and of judging which reasons are stronger than others, lies in the fact that such language implies a common, neutral means of measuring the reasons. The very contrast, however, between morality and self-interest suggests that there can be no such means. The agent is faced with a choice between points of view and perspectives. From within a point of view or perspective, there can be weighing. What remains a mystery is how any agent could measure the relative strengths of the two kinds of consideration from neither the moral or prudential point of view but from a neutral standpoint.[4]

Bryne’s criticism seems to be this. Layman example imagines an agent “weighing” impartial reasons against prudential reasons against each other and attempting to answer the question as to which reasons are stronger or take precedence. This implies there is some rational perspective, which is neutral between prudence and impartial demands, which can weigh and adjudicate them in a conflict.

Bryne thinks this is misleading. The clash between prudential and impartial reasons involves a clash between requirements justified by incommensurable points of “points of view” or “perspectives”. These points of view are perspectives on what interests to take into account and how much weight to give them. The impartial point of view is a perspective that takes into account everyone’s interests and forms a conclusion based on giving these interests equal weight and consideration. From this point of view, you always have decisive reasons to do what is impartially required. By contrast, the prudential point of view is a view that only gives takes into account the interest of the individual agent and gives equal weight to the future and past interests of this individual agent. From this perspective, you should always act in your long-term self-interest.

Because these are differing perspectives on what interests to take into account and how much weight to give conflicting interests, there can be no question-begging way of weighing the conclusions of each procedure against each other. You can weigh reasons for and against actions in accord with one or more of these perspectives. You can have allegiance to one or both perspectives, and weigh from that perspective. One can also give up allegiance to one perspective in favour of another. But, when they clash, you cannot accept both perspectives simultaneously and weigh them against each other.

I am inclined to think Byrne’s response here misses the point. Consider how Ms Poore’s case appears on Bryne’s analysis. Ms. Poore “faces the choice of stealing the money or living in grinding poverty the rest of her life”. However, you analyse this; she still has to choose what to do in this situation; she must act one way or the other. In Bryne’s terms, we can ask Which perspective should she use in making the decision and weighing the relevant factors. Which point of view should she give allegiance to? Which should she give up allegiance to? Bryne’s analysis seems to imply there is no reason one can give for or against either answer. There is no “rational” or “neutral point of view” by which she can make this choice. The implication is that Ms Poore does not have stronger or weightier reasons to do what is impartially required. This isn’t because prudential reasons sometimes outweigh or trump impartial reasons, but because one cannot coherently claim one is weightier than the other without begging the very question at issue.

Concerns about the dualism of practical reason are concerns about a specific sort of practical dilemma. Suppose it is not always in one’s long-term self-interest to act according to impartial demands. This will mean impartial demands sometimes come into conflict with prudential requirements. When they do, we face the question: What reason is there to act impartially, rather than in one’s self-interest. What reason do we have for assuming that impartial demands are always stronger or weightier than prudential requirements when the two clash? The concern is that no answer to this question is forthcoming. If impartial and prudential requirements cannot be weighed against each other, then its hard to see how the former can always be weightier or take precedence in a clash. If they are incommensurable, we cannot have reasons for preferring one to the other.

Several commentators argue that this is precisely Sidgwick’s point when he agonised over the dualism of practical reason[5]. Note the argument Sidgwick gives for [3]

[U]nless the egoist affirms, implicitly or explicitly, that his own greatest happiness is not merely •the rational ultimate end for himself but •a part of universal good; and he can avoid the ‘proof’ of utilitarianism by declining to affirm this. Common sense won’t let him deny that the distinction between himself and any other person is real and fundamental; so it puts him in a position to think: ‘I am concerned with the quality of my existence as an individual in a fundamentally important sense in which I am not concerned with the quality of the existence of anyone else’; and I don’t see how it can be proved that this distinction ought not to be taken as fundamental in fixing the ultimate goal of an individual’s rational action… If an egoist isn’t moved by what I have called proof, the only way of arguing him into aiming at everyone’s happiness is to show that this gives him his best chance of greatest happiness for himself. And even if he admits that the principle of rational benevolence is self-evident, he may still hold •that it is irrational for him to sacrifice his own happiness to any other end;[6]

Here, Sidgwick imagines an “egoist”: someone who has “given allegiance” to the prudential point of view and weighs reasons in accord with this perspective. This egoist discovers that an impartial point of view would prohibit some action. Does the egoist have any reason to heed this prohibition? Sidgwick argues that, unless it can be shown that doing so is in his interest, the answer is no. From the egoist’s “perspective” or “point of view,” the effects of the action on his long-term interests is the only factor that carries weight in the decision. Providing does not implicitly give allegiance to an impartial point of view, or he is willing to give up any allegiance he does have to it; he will have no reason to do what is impartially required. Nor does he have any question-begging reason why he should switch allegiance to this point of view.

On this interpretation: the dualism of practical reason is the problem that impartial and prudential requirements are requirements justified from incommensurable points of view. Because human beings recognise both prudential and impartial reasons for acting in their practical reasoning, they implicitly give allegiance to both. This is not a problem if their requirements are consistent. But if they contradict each other, we will be rationally committed both to both doing and not doing the same action. The incommensurability of these perspectives means there is no rational basis for resolving the contradiction in favour of impartiality. Sidgwick writes:

[W]here we find a conflict between self-interest and duty, practical reason, being divided against itself, would cease to be a motive on either side. The conflict would have to be decided by which of two groups of non-rational impulses had more force. So we have this: •The harmony of duty and self-interest is a hypothesis that is required if we are to avoid a basic contradiction in one chief part of our thought.[7]

We can put it this way: Either prudential and impartial reasons are commensurable, or they are incommensurable. If they are commensurable, then when these requirements clash, we will need some reason for thinking that impartial reasons are always weightier. The Ms Poore case suggests this is not the case. By contrast, suppose that prudential and impartial requirements are incommensurable perspectives, and we cannot weigh them against each other. If they clash, we will have to choose which perspective to follow, and we will have no reason to follow one or the other. It will simply be an arbitrary act of allegiance. Either way, we will lack decisive reasons always to do what is impartiality required.

[1] C. Stephen Layman “God and the Moral Order” Faith and Philosophy, 23 (2006): 307

[2] Layman, “God and the Moral Order” 308

[3] Peter Bryne “God and the Moral Order: A Reply to Layman” Faith and Philosophy, 23:2 (2006): 201

[4] Bryne, “God and the Moral Order: A Reply to Layman” 206-207:

[5] See for example, Derek Parfit On What Matters (Volume 1) (Oxford: Oxford University Press : 2011) 130-134. See also Francesco Orsi, “The Dualism of the Practical Reason: Some Interpretations and Responses” Etica & Politica / Ethics & Politics, 10:2 (2008): 25-26

[6] Henry Sidgwick, The Method of Ethics, 242 available at https://www.earlymoderntexts.com/assets/pdfs/sidgwick1874.pdf accessed 20/3/21

[7] Henry Sidgwick, The Method of Ethics, 284 available at https://www.earlymoderntexts.com/assets/pdfs/sidgwick1874.pdf accessed 20/3/21