Derek Parfit, one of the most influential contemporary philosophers, died last January. The day before his death, he submitted what seems to be his last paper to the philosophy journal Philosophy and Public Affairs. In this paper, Parfit tackles the famous “non-identity problem” that he has himself settled in Reasons and Persons almost 35 years ago. Though unachieved, the paper is quite interesting because it appears to offer a way to avoid the not less famous “repugnant conclusion”. I describe below Parfit’s tentative solution and also add some comments on the role played by moral intuitions in Parfit’s (and other moral philosophers’) argumentation.
Parfit is concerned with cases where we have to compare the goodness of two or more outcomes where different people exist across these outcomes. Start first with Same Number cases, i.e. cases where at least one person exists in one outcome but no in the other but where the total number of people is the same. Example 1 is an instance of such a case (numbers denote quality of life according to some cardinal and interpersonally comparable measure):
Example 1
| Outcome A | Ann 80 | Bob 60 | ——– |
| Outcome B | ——— | Bob 70 | Chris 20 |
| Outcome C | Ann 20 | ——— | Chris 30 |
How should we compare these three outcomes? Many moral philosophers entertain one kind or another of “person-affecting principles” according to which betterness or worseness necessarily depend on some persons being better (worse) in an outcome than in another one. Consider in particular the Weak Narrow Principle:
Weak Narrow Principle: One of two outcomes would be in one way worse if this outcome would be worse for people.
Since it is generally accepted that we cannot make someone worse by not making her exist, outcome A should be regarded as worse (in one way) than outcome B by the Weak Narrow Principle. Indeed, Bob is worse in A than in B while the fact that Ann does not exist in B cannot make her worse than in A (even though Ann would have a pretty good life if A were to happen). By the same reasoning, C should be considered as worse than A and B worse than C. Thus the ‘worse than’ relation is not transitive. Lack of transitivity may be seen as dubious but is not in itself sufficient to reject the Weak Narrow Principle. Note though that if we have to compare the goodness of the three outcomes together, we are left without any determinate answer. Consider however:
Example 2
| Outcome D | Dani 70 | Matt 50 | ——– | ——– |
| Outcome E | ——— | Matt 60 | Luke 30 | ——– |
| Outcome F | ——— | ——— | Luke 35 | Jessica 10 |
According to the Weak Narrow Principle, D is worse than E and E is worse than F. If we impose transitivity on the ‘worse than’ relation, then D is worse than F. Parfit regards this kind of conclusion as implausible. Even if we deny transitivity, the conclusion than E is worse than F is also hard to accept.
Given that the Weak Narrow Principle leads to implausible conclusion in Same Number cases, it is desirable to find alternative principles. In Reasons and Persons, Parfit suggested adopting impersonal principles that do not appeal to facts about what would affect particular people. For instance,
Impersonal Principle: In Same Number cases, it would be worse if the people who existed would be people whose quality of life would be lower.
According to this principle, we can claim that F is worse than E which is worse than D. Obviously, ‘worse than’ is transitive. What about Different Number cases (i.e. when the number of people who exist in one outcome is higher or lower than in another one)? In Reasons and Persons, Parfit originally explored an extension of the Impersonal Principle:
The Impersonal Total Principle: It would always be better if there was a greater sum of well-being.
Parfit ultimately rejected this last principle because it leads to the Repugnant Conclusion:
The Repugnant Conclusion: Compared with the existence of many people hose quality of life would be very high, there is some much larger number of people whose existence would be better, even though these people’s lives would be barely worth living.
In his book Rethinking the Good, the philosopher Larry Temkin suggests avoiding the repugnant conclusion by arguing that the ‘all things considered better than relation’ is essentially comparative. In other words, the goodness of a given outcome depends on the set of outcomes with which it is compared. But this has the obvious consequence that the ‘better than’ relation is not necessarily transitive (Temkin claims that transitivity applies only to a limited part of our normative realm). Parfits instead sticks to the view that goodness is intrinsic and suggests an alternative approach through another principle:
Wide Dual Person-Affecting Principle: One of two outcomes would be in one way better if this outcome would together benefit people more, and in another way better if this outcome would benefit each person more.
Compare outcomes G and H on the basis of this principle:
Outcome G: N persons will exist and each will live a life whose quality is at 80.
Outcome H: 2N persons will exist and each will live a life whose quality is at 50.
According to the Wide Dual Person-Affecting Principle, G is better than H in at least one way because it benefits each person more, assuming that you cannot be made worse by not existing. H may be argued to be better than G on another way, by benefiting people more, at least on the basis of some additive rule. Which outcome is all things considered better remains debatable. But consider
Outcome I: N persons will exist and each will live a life whose quality is at 100.
Outcome J: 1000N persons will exist and each will live a life whose quality is at 1.
Here, although each outcome is better than the other on one respect, it may be plausibly claimed that I is better all things considered because the lives in J are barely worth living. This may be regarded as sufficient to more than compensate for the fact that the sum of well-being is far superior in J than in I. This leads to the following conclusion:
Analogous Conclusion: Compared with the existence of many people whose lives would be barely worth living, there is some much higher quality of life whose being had by everyone would be better, even though the numbers of people who exist would be much small.
This conclusion is consistent with the view that goodness is intrinsic and obviously avoids the repugnant conclusion.
I would like to end this post with some remarks with the role played by moral intuitions in Parfit’s reasoning. This issue had already came to my mind when reading Partit’s Reasons and Persons as well as Temkin’s Rethinking the Good. Basically, both Parfit and Temkin (and many other moral philosophers) ground their moral reasoning on intuitions about what is good/bad or right/wrong. For instance, Parfit’s initial rejection of impersonality principles in Reasons and Persons was entirely grounded on the fact that they seem to lead to the repugnant conclusion which Parfit regarded as morally unacceptable. The same is true for Temkin’s arguments against the transitivity of the ‘all things considered better than’ relation. Moral philosophers seem mostly to use a form of backward reasoning about moral matters: take some conclusions as intuitively acceptable/unacceptable or plausible/implausible and then try to find principles that may rationalize our intuitions about these conclusions.
As a scholar in economics & philosophy with the background of an economist, this way of reasoning is somehow surprising me. Economists who are thinking about moral matters are generally doing so from a social choice perspective. The latter almost completely turns the philosopher’s reasoning on its head. Basically, a social choice theorists will start from a small set of axioms that encapsulate basic principles that may be plausibly regarding as constraints that should bind any acceptable moral view. For instance, Pareto principles are generally imposed because we take as a basic moral constraint the fact that everyone is better (in some sense) in a given outcome than in another one make the former better than the latter. The social choice approach then consists in determining which social choice functions (i.e. moral views) are compatible with these constraints. In most of the case, this approach will not be able to tell which moral view is obligatory; but it will tell which moral views are and are not permissible given our accepted set of constraints. The repugnant conclusion provides a good illustration: in one of the best social choice treatment of issues related to population ethics, John Broome (a philosopher but a former economist) rightly notes that if the “repugnant” conclusion follows from acceptable premises, then we should not reject it on the ground that we regarded as counterintuitive. The same is true for transitivity: the fact that it entails counterintuitive conclusion is not sufficient to reject it (at least, independent argument for rejection are needed).
There are two ways to justify the social choice approach to moral matters. The first is the fact that we generally have a better understanding of “basic principles” than of more complex conclusions that depend on a (not always well-identified) set of premises. It is far easier to discuss the plausibility of transitivity or of Pareto principles in general than to assess moral views and their more or less counterintuitive implications. Of course, we may also have a poor understanding of basic principles but the attractiveness of the social choice approach is precisely that it helps to focus the discussion on axioms (think of the literature on Arrow’s impossibility theorem). The second reason to endorse the social choice approach on moral issues is that we now start to understand where our moral intuitions and judgments are coming from. Moral psychology and experimental philosophy tend to indicate that our moral views are deeply rooted in our evolutionary history. Far from vindicating them, this should quite the contrary encourage us to be skeptical about their truth-value. Modern forms of moral skepticism point out that whatever the ontological status of morality, the naturalistic origins of moral judgments do not guarantee and actually make highly doubtful that whatever we believe about morality is epistemically well-grounded.
Bargaining Game 