2. The Mere Addition Argument for Welfare Diffusion

We begin with a few technical preliminaries. As was implicit earlier, I shall use real numbers to represent wellbeing levels. Positive numbers represent lives worth living, negative numbers represent lives worth not living, and zero represents neutral lives. Greater numbers represent better lives.

This leaves open the question of how ratios of the differences between wellbeing levels are to be understood. I shall use the following scale: for some fixed good quality of life $q$ , a life is at $x \ge 0$ units of wellbeing if and only if it is equally as good as a life which lasts for $x$ years at some constant good quality $q$ . A life is at $ - x$ if and only if one would rationally be indifferent between certainty of a life at $x$ and a 50-50 gamble yielding a life at either $ - x$ or $x$ . ^{Footnote 4}

A population is a finite set of possible people with associated wellbeing levels.Footnote ⁵ Populations represent the distributions in which precisely these people exist, with lives at the respective wellbeing levels, and nobody else exists. ${p_i}[{w_i}]$ denotes the population consisting of just person ${p_i}$ at level ${w_i}$ ; similarly, if X is a set of possible people, $X[{w_i}]$ denotes the population containing the $X$ -people at level ${w_i}$ , and nobody else. Populations are disjoint when they have no persons in common. If $X$ and $Y$ are disjoint populations, we may write $X + Y$ for the population which consists of the X-people at their respective levels, the $Y$ -people at their respective levels, and nobody else. ^{Footnote 6} (When I write $X + Y$ , I am always assuming that $X$ and $Y$ are disjoint; quantifiers should be understood to be restricted accordingly.)

We shall be interested in the at-least-as-good-as relation, denoted by $ \succcurlyeq\! $ . I take this to be a transitive binary relation on populations. ^{Footnote 7} This is not a completely innocent assumption. Some philosophers, most notably Larry Temkin (Reference Temkin1987, Reference Temkin1996, Reference Temkin2012) and Stuart Rachels (Reference Rachels1998, Reference Rachels2001, Reference Rachels, Ryberg and Tännsjö2004), have argued that the at-least-as-good-as relation is not transitive. Others believe that the at-least-as-good relation is option-set-dependent, and hence cannot be understood to be a binary relation on populations. ^{Footnote 8} I’m sceptical of both positions, but I won’t argue against them in this paper. Let’s set them aside for the time being.

That is enough in the way of background. Let’s see how the core commitment of Prioritarianism, when conjoined with the Mere Addition Principle, implies the desirability of welfare diffusion. To begin with, let’s set these principles out more precisely. (Two of these principles unavoidably look a bit complicated when stated precisely, but they are easy to understand by examining Figures 1 and 2.)

Figure 1.

Strong Pigou-Dalton.

Figure 2.

Different-Number Egalitarian Dominance: If ${x\vert{X}\vert} \gt {y\vert{Y}\vert},\, \rm{then}\ {X \ge Y}$ .

We shall understand the core commitment of Prioritarianism to be the principle of

Strong Pigou-Dalton. Let ${w^ - } \lt w$ be any wellbeing levels, and let a be any quantity of additional wellbeing. There is a small positive quantity of wellbeing $\varepsilon '$ such that for any possible persons ${p_i}$ and ${p_j}$ , and any disjoint unaffected background population U, if $0 \le \varepsilon \le \varepsilon'$ then

$U + {p_i}[w] + {p_j}[{w^ - } + a - \varepsilon ] \succ U + {p_i}[w + a] + {p_j}[{w^ - } + \varepsilon ]$

Strong Pigou-Dalton says that slightly smaller benefits to the worse off make the world better than slightly larger benefits to the better off. Put another way, transfers of wellbeing from the better-off to the worse-off make the world better even when they are slightly ‘leaky’, resulting in a small loss of total wellbeing. Prioritarians cannot reject this principle.

Next, we have the Mere Addition Principle:

As I mentioned earlier, Mere Addition does not imply that an addition of lives worth living is at least as good, or better, than no addition at all. Principles of that sort are suspect because they conflict with the Evaluative Procreation Asymmetry, according to which bringing lives worth living into existence never makes the world better. ^{Footnote 9} Mere Addition, as stated here, faces no such objection.

Finally, we need a principle which guarantees that welfare diffusion is not desirable. This shall be:

Different-Number Egalitarian Dominance tells us that smaller populations with greater total wellbeing and perfect equality of wellbeing are at least as good as larger populations with lesser total wellbeing. It is restricted to cases where the people in the smaller population also exist in the larger population. This restriction ensures that everyone who exists in the smaller population is better off, even if Existence Comparativism is false. Different-Number Egalitarian Dominance is therefore consistent with the narrow person-affecting principle, on which an outcome can only be better than another if it is better for some particular person.

Different-Number Egalitarian Dominance encodes avoidance of the Welfare Diffusion Objection: population axiologies which do not satisfy Different-Number Egalitarian Dominance say that welfare diffusion is sometimes desirable, or at least say that sometimes, welfare diffusion is not undesirable. ^{Footnote 10} So population axiologies which do not satisfy Different-Number Egalitarian Dominance are open to the Welfare Diffusion Objection.

Putting these three principles together, it can be shown that

Proposition 1. No population axiology satisfies Strong Pigou-Dalton, Mere Addition and Different-Number Egalitarian Dominance.

Proof. Let ${p_i}$ and ${p_j}$ be any two possible people. Apply the Strong Pigou-Dalton principle with an empty unaffected background population, higher wellbeing level 50, lower wellbeing level 0, and 50 units of potential additional wellbeing. This tells us that there is some small positive quantity of wellbeing such that

${p_i}[50] + {p_j}[50 - \varepsilon ] \succ {p_i}[100] + {p_j}[\varepsilon ]$

Different-Number Egalitarian Dominance implies that

${p_i}[100] \succcurlyeq {p_i}[50] + {p_j}[50 - \varepsilon ]$

Transitivity then implies that

${p_i}[100] \succ {p_i}[100] + {p_j}[\varepsilon ]$

which contradicts Mere Addition.

To get this argument through, we applied Different-Number Egalitarian Dominance to the case of comparing a single-person population with greater total wellbeing to a larger population with slightly lesser total wellbeing. Different-Number Egalitarian Dominance might seem suspicious in exactly these kinds of cases: it might be reasonable, for example, to think that it would be better for there to be ten billion people, at wellbeing level one hundred, than for there to be one person at level one hundred billion.

However, this objection can be brushed aside, because Proposition 1 still goes through even if we weaken Different-Number Egalitarian Dominance so that it applies only to populations of size $n$ or larger (no matter how large $n$ is, and assuming that there are at least $2n$ possible people). If ${X_i}$ and ${X_j}$ are disjoint sets of $n$ possible people each, observe that by applying Strong Pigou-Dalton and transitivity n times, we can show that ^{Footnote 11}

${X_i}[50] + {X_j}[50 - \varepsilon ] \succ {X_i}[100] + {X_j}[\varepsilon ]$

From here, following the same strategy as in the proof of Proposition 1, it is easy to apply Different-Number Egalitarian Dominance and transitivity in order to show that

${X_i}[100] \succ {X_i}[100] + {X_j}[\varepsilon ]$

which contradicts Mere Addition.

Since Prioritarians cannot deny Strong Pigou-Dalton, the upshot of Proposition 1 is that they must choose between Mere Addition and Different-Number Egalitarian Dominance.

In the next section, I shall argue that Prioritarians cannot reasonably reject Mere Addition. I shall also argue that they are implicitly committed to the principle of Separability, which says that unaffected people can be ignored when comparing populations. Separability in turn provides strong support for Mere Addition, and even stronger support for a weaker version of Mere Addition which, if we slightly strengthen our Pigou-Dalton principle, implies the desirability of welfare diffusion.

3. Mere Addition and Separability

What distinguishes Prioritarianism from Egalitarianism? Parfit (Reference Parfit1997: 214) answers: while Egalitarians are concerned with relations between people’s wellbeing levels and the wellbeing levels of others, Prioritarians are solely concerned with people’s absolute wellbeing levels. Consider a situation in which one person is at 100 and another is at wellbeing level 0, when both could instead have been at wellbeing level 50. Egalitarians decry this situation because it involves inequality: the less well-off person is not as well off as the better-off person. Prioritarians decry the same situation on different grounds: for them, the situation is regrettable not because it involves inequality, but because although there is nothing bad about the first person being at level 100 rather than level 50, it would have been better for the second person to be at level 50 rather than level 0, even though the two potential benefits are of the same size.

The Prioritarian concern for people’s absolute wellbeing levels provides immediate support for the Mere Addition Principle. ^{Footnote 12} Consider the application of this principle in the proof of Proposition 1. Mere Addition there implied that is not worse than ${p_i}[100]$ . Egalitarians can reject this claim. They can say that, because the existence of ${p_j}$ introduces inequality, it would be better if only ${p_i}$ were to exist. But Prioritarians cannot say the same thing. Since they are concerned only with people’s absolute levels of wellbeing, they cannot appeal to relations between ${p_i}$ ’s wellbeing and ${p_j}$ ’s wellbeing when both exist. On the face of it, Prioritarians can say that it is bad for ${p_j}$ to exist only if existence is bad for ${p_j}$ . But that cannot be the case: while ${p_j}$ has only a low positive wellbeing level, a low positive level still represents a life worth living, though perhaps only barely.

We can make another, more precise, argument from the sole concern with absolute levels to the Mere Addition Principle. A sole concern for people’s absolute wellbeing levels is captured by the principle of

Separability is widely accepted by Prioritarians. Indeed, Adler and Holtug (Reference Adler and Holtug2019: 104) take a version of Separability to a defining feature of Prioritarianism. The version of Separability they are talking about is restricted to same-person cases, while mine is unrestricted (and needs to be). ^{Footnote 13} But a sole concern for people’s absolute wellbeing levels supports the unrestricted version of Separability just as well as it supports the restricted version. If unrestricted Separability is false, then the relative contributive values of populations $X$ and $Z$ depend not only on the absolute levels of the persons involved in $X$ and $Y$ , but also on the status of the unaffected people in population $Z$ . Thus, one cannot deny unrestricted Separability without thereby expressing a concern for more than just people’s absolute wellbeing levels.

Separability is hard to square with the negation of Mere Addition. If we deny Mere Addition, we think that sometimes it is worse to add lives worth living to the world. If we accept Separability as well, then we will have to infer that it is always worse to add such lives to the world. This claim is implausible in its own right. It can also be shown to be incompatible with a very compelling principle, namely the

At least, this is so if we accept

Non-Absolute Priority. For any positive quantity of wellbeing $x$ , there is some sufficiently small positive quantity of wellbeing such that for any persons ${p_i}$ and ${p_j}$ , and any disjoint unaffected background population U,

$U + {p_i}[\varepsilon ] + {p_j}[\varepsilon ] \nsucc U + {p_i}[x] + {p_j}[ - \varepsilon ]$

Non-Absolute Priority says that we should not give absolute priority to those who are slightly below the neutral level, over those who are slightly above the neutral level. The opposite view, Absolute Prioritarianism, says that those who are below the threshold of a life worth living are to be prioritized absolutely over those who are above the threshold. On this view, it would be better to spare one person from a pinprick which would push them slightly below the neutral level, rather sparing trillions of people from suffering much greater harms which would not push them below the neutral level. Since most people do not find this kind of view very plausible, I shall not discuss it further. ^{Footnote 15}

Given Non-Absolute Priority and Separability, the Absolute Value Principle implies Mere Addition. We can show this by contradiction. If Mere Addition is false, there is some case in which an addition of a life at positive wellbeing level $x$ is worse than no addition at all. ^{Footnote 16} By Separability, adding a person (let’s say ${p_2}$ ) at level $x$ is therefore always worse than no adding no one. Now consider the following three populations.

1. $\hskip 125pt{A_{1}\quad{p_1}[ - \varepsilon ]}$

2. $\hskip 125pt{B_1}\quad{p_1}[ - \varepsilon ] + {p_2}[x]$

3. $\hskip 125pt{C_1}\quad{p_1}[\varepsilon ] + {p_2}[\varepsilon ]$

By the negation of Mere Addition and Separability, ${B_1}$ is worse than ${A_1}$ . By the Absolute Value Principle, ${A_1}$ is worse than ${C_1}$ . Transitivity then implies that ${B_1}$ is worse than ${C_1}$ . This contradicts Non-Absolute Priority.

I find the Absolute Value Principle utterly compelling, so this argument for Mere Addition seems to me decisive. But not everyone accepts the Absolute Value Principle. Critical Level (or Critical Range) Prioritarians, for example, believe that it can be worse (or not better) for there to be many lives that are positive, but below a ‘critical level’ ${x^*} \gt 0$ , rather than for there to be fewer lives at a negative wellbeing level. ^{Footnote 17}

It turns out, however, that even Critical Level Prioritarians do not avoid the Welfare Diffusion Objection. We can adapt the previous argument to make do with a weaker version of the Absolute Value Principle, which even Critical Level (and most Critical Range) Prioritarians would accept. We can then only get a weaker version of Mere Addition out, but it will be enough for our purposes. The weaker version of the Absolute Value Principle says that

Critical Level Prioritarians say that a large number of lives barely worth living can be worse than a smaller number of lives worth not living. But they do not say that a large number of excellent lives can be worse than a smaller number of negative lives. The former claim is pretty implausible, but one might perhaps reluctantly accept it in order to avoid the Repugnant Conclusion. The latter claim is even more implausible, and cannot be justified on this basis.

We also need a slightly different, but still compelling, Non-Absolute Priority condition I shall call Non-Absolute Priority 2. This condition is illustrated by Figure 3 over the page. The precise statement of the condition is as follows:

Non-Absolute Priority 2. For some sufficiently small positive quantity of wellbeing $\varepsilon $ , if ${\cal W}$ is any bounded interval of non-negative wellbeing levels, there is a sufficiently large positive quantity of wellbeing $\delta '$ such that given any unaffected background population U, if $\varepsilon \le \varepsilon '$ , $\delta \ge \delta '$ and ${w_i},{w_j}$ are in ${\cal W}$ , then

$U + {p_i}[{w_i} - \varepsilon ] + {p_j}[{w_j} + \delta ] \succ U + {p_i}[{w_i}] + {p_j}[{w_j}]$

Figure 3.

Non-Absolute Priority 2.

This principle looks a little complicated, but essentially it just says that it is always better to provide a sufficiently large benefit to a better-off person, rather than a very small benefit to a worse-off person. The required size of the benefit to the better-off person can increase as the gap between the two increases (which is why we quantify over ${\cal W}$ ). Note also that Non-Absolute Priority 2 only requires us to avoid giving absolute priority to people with wellbeing levels which are, at worst, only slightly negative.

Let’s now see how these principles imply a weaker version of Mere Addition. Consider the following three populations, where a is a sufficiently high wellbeing level for the Weak Absolute Value Principle to apply, represents an arbitrarily small quantity of wellbeing, and ${a^ + }$ is some arbitrarily good wellbeing level:

1. $\hskip 125pt{A_2}\quad{p_i}[ - \varepsilon ]$

2. $\hskip 125pt{B_2}\quad{p_i}[ - \varepsilon ] + {p_j}[{a^ + }]$

3. $\hskip 125pt{C_1}\quad{p_i}[a] + {p_j}[a]$

By applying Non-Absolute Priority 2 finitely many times, it can be shown that ${B_2}$ is better than ${C_2}$ . ^{Footnote 18} The Weak Absolute Value Principle implies that ${C_2}$ is better than ${A_2}$ . Transitivity then implies that ${B_2}$ is better than ${A_2}$ . ^{Footnote 19} Given Separability, this constitutes a proof of

This weaker version of the Mere Addition Principle is enough to commit the Prioritarian to the desirability of welfare diffusion. To show this, we need a same-person Prioritarian principle which is slightly different to Strong Pigou-Dalton. This principle, which is illustrated by Figure 4 above, is

1. (i) $N[b] + {p_i}[b] \succ N[c] + {p_i}[a]$

2. (ii) $nc \gt (n + 1)b$

Figure 4.

Priority-Utility Trade-Off.

As the name suggests, Priority-Utility Trade-Off requires that we give priority to the worse off in such a way that we sometimes sacrifice a significant amount of total utility. More precisely, it says that for any level of wellbeing $a$ , we can find a large number of people at a higher level of wellbeing $c$ such that, rather than having the unequal outcome in which one person at level a and the large number at level $c$ exist, it would be better if instead all of these people existed at an intermediate wellbeing level b, even though this would mean a sacrifice of more than $a$ units of total wellbeing. For example, although wellbeing level 100 is the level of a very good life by contemporary standards, Prioritarians (and Egalitarians) will presumably think that, rather than having one person at level 100 and another person at level 1001, it would be better if instead both were at level 500, even though this would come at the cost of more than 100 units of total wellbeing. As far as I can see, Prioritarians cannot reject this principle.

It can now be shown that

Proposition 2. No population axiology satisfies Priority-Utility Trade-off, Weak Mere Addition and Different-Number Egalitarian Dominance.

Proof. Let $a$ be a wellbeing level witnessing Weak Mere Addition (that is, additions at level $a$ are never worse). Priority-Utility Trade-off implies that there are wellbeing levels $b \gt c$ , both of which are greater than $a$ , a set $N$ of possible people of size $n$ and a possible person ${p_i}$ such that $nc \gt (n + 1)b$ and

$N[b] + {p_i}[b] \succ N[c] + {p_i}[a].$

Now compare the population $N[c]$ with $N[b] + {p_i}[b]$ . $N[c]$ has total wellbeing $nc$ , which (from Priority-Utility Trade-Off) is greater than $(n + 1)b$ (the total wellbeing of $N[b] + {p_i}[b]$ ). Furthermore, $N[c]$ is a perfectly equal population of good lives, each person in $N[c]$ exists in $N[b] + {p_i}[b]$ , and each person in $N$ is better off in the former population than in the latter. Different-Number Egalitarian Dominance therefore implies that

$N[c] \succ N[b] + {p_i}[b].$

By transitivity, we then have

$N[c] \succ N[c] + {p_i}[a],$

which contradicts Weak Mere Addition.

We also have:

Since the first four of these principles are satisfied by all plausible versions of Prioritarianism, the upshot is that no plausible version of Prioritarianism avoids the Welfare Diffusion Objection. Note also that even Prioritarians who deny Separability do not necessarily escape the Welfare Diffusion Objection. Proposition 2 does not appeal to Separability directly: I have used Separability only to support (Weak) Mere Addition. But (Weak) Mere Addition is independently very plausible, and would be hard to deny even for those who do not find Separability particularly compelling.

4. A Related Argument for Totalism

The arguments of §2 and §3 are not only of interest to Prioritarians and their critics. Proposition 1, which we used to establish that Prioritarians cannot accept Mere Addition without leaving themselves open to the Welfare Diffusion Objection, can be repurposed into an argument for Totalism. Recall that Proposition 1 shows that no population axiology satisfies Mere Addition, Different-Number Egalitarian Dominance and Strong Pigou-Dalton. Strong Pigou-Dalton is controversial (albeit still intuitively compelling) because it says that benefits to the worse off matter more than benefits to the better off. A weaker Pigou-Dalton principle, which only says that benefits to the worse off matter at least as much as benefits to the better off, is accepted by virtually everyone:

$U + {p_i}[{w^ - } + a] + {p_j}[w] \succcurlyeq U + {p_i}[{w^ - }] + {p_j}[w + a]$

Assume also a slight strengthening of Mere Addition, which says that additions of good or neutral lives cannot make the world worse. Call this principle Mere Addition*. Finally, consider a marginally stronger version of Different-Number Egalitarian Dominance, which applies to neutral as well as good lives and drops the requirement that those who exist in the population of better-off people must also exist in the population of worse-off people:

We shall now see that these three principles together imply

That is, we have

Let C be an arbitrary non-empty population of good or neutral lives. Let ${p_i}$ be some person in $C$ , and let $C'$ be the set of people in $C$ , except for ${p_i}$ . Define populations $A$ and $B$ to be:

1. $\hskip 85pt{A\ \ \ {p_i}[T(C)]}$

2. $\hskip 85pt{B\ \ \ {p_i}[T(C)] + C'[0]}$

Different-Number Egalitarian Dominance* implies that $A$ is at least as good as $C$ . $C$ is obtainable from $B$ by means of a series of pure transfers of wellbeing from better-off to worse-off, taking wellbeing from ${p_i}$ each time. Weak Pigou-Dalton therefore implies that $C$ is at least as good as $B$ . Applying transitivity, we find that $A$ is at least as good as $B$ . But Mere Addition* implies that $B$ is not worse than $A$ . It follows that $A$ and $B$ must be equally good. ^{Footnote 22} Recalling that $A$ is at least as good as $C$ and that $C$ is at least as good as $B$ , we can conclude that $A$ and $C$ are equally good too.

5. Objections and Replies

6. Concluding remarks

I have argued that the Welfare Diffusion Objection poses a significant challenge to Prioritarianism, even if we think of Prioritarianism as a theory of same-person comparisons only. Importantly, I have assumed throughout this paper that the at-least-as-good-as relation is both option-set-independent and transitive. If Prioritarians want to avoid the Welfare Diffusion Objection, their best bet may be to challenge one or the other of these assumptions. They might say that in order to properly restrict Prioritarianism to same-person choices, transitivity needs to be similarly restricted so that it does not allow one to chain together betterness claims which come from Prioritarian comparisons of same-person choices and non-Prioritarian comparisons of different-number choices. ^{Footnote 28} Or, they might say that the Prioritarian weighting of benefits applies only to gains and losses which would render people better or worse off than they otherwise would have been. Given Existence Comparativism, the resulting version of Prioritarianism would either have to be intransitive (if losses and gains depend on the two outcomes being evaluatively compared) or option-set-dependent (if losses and gains depend on the set of relevant alternatives). ^{Footnote 29} Taking any such path would be a significant departure from traditional ways of thinking about value, and would open the Prioritarian to other objections, like the prospect of susceptibility to value pumps. ^{Footnote 30} Perhaps such objections can be answered, or perhaps they cannot. ^{Footnote 31} Another possibility in the vicinity is to abandon axiological or ‘telic’ Prioritarianism, but retain a deontic version of Prioritarianism. Because the ‘ought-to-bring-about-rather-than’ relation is less obviously transitive than the ‘better-than’ relation, intransitive deontic Prioritarianism seems to me more plausible than its intransitive telic counterpart.

There are several options for those who are not prepared to give up transitivity or option-set-independent betterness. One is to simply bite the bullet and accept the desirability of welfare diffusion. While this position seems to me unattractive, it might fairly be said that every transitive population axiology takes one unattractive position or another. The desirability of welfare diffusion is not clearly more implausible than other controversial positions in population axiology, such as acceptance of the Repugnant Conclusion. ^{Footnote 32} It also may be that adopting a version of Prioritarianism which implies the desirability of welfare diffusion has payoffs elsewhere. For instance, unlike Totalism, Total Prioritarianism has the plausible implication that it would be worse to create a number of people at wellbeing level $ - x$ and the same number of people at $x$ than it would be to create nobody at all (Holtug Reference Holtug2010: 255). ^{Footnote 33} Total Prioritarianism also implies, again rather plausibly, that it can be better for there to be more total negative wellbeing spread thinly among a larger number of people than for there to be less total negative wellbeing spread thickly among a smaller number of people (Holtug Reference Holtug2010: 256–257).

How bad would it be for a Prioritarian to accept the desirability of welfare diffusion? The precise answer to this question depends on the details of how much priority is to be given to the worse-off. But here’s a rough answer. I expect that many Prioritarians will believe that it is better to bring two people from level 1 to level 20 than it is to bring one person from level 20 to level 100. If that is true, and Mere Addition is also true, then it would not be worse for there to be thirty billion people at level 20 than it would be for there to be ten billion people at level 100. I find this last claim difficult to believe.

Another option is to deny the Mere Addition principle. As I argued extensively in §3, this option should not be taken by a Prioritarian. But one could abandon Prioritarianism for this reason, and instead accept Egalitarianism. This seems to me a reasonable response to the arguments of this paper: it is not crazy to claim that it can be worse to add people with lives worth living when (and because) doing so would introduce significant inequality. That said, it’s worth mentioning that Proposition 2 shows that rejecting Mere Addition alone is not enough to avoid the Welfare Diffusion Objection: one would also need to reject Weak Mere Addition, which might be a hard pill to swallow even for an Egalitarian.

A final option is to accept all of the premises of Proposition 3, taking the desirability of welfare diffusion to rule out Prioritarianism and taking Mere Addition to rule out Egalitarianism. One would then be left with Totalism for Good Populations. The obvious next step is to accept unrestricted Totalism, but one is not actually forced to this position. One can, compatibly with the premises of Proposition 3, give priority to the worse off whenever the worse off are below the neutral level at the outset. There is more to be said for this restricted version of Prioritarianism than it might at first seem. Roger Crisp (Reference Crisp2003: 755), noting the apparent absurdity of prioritizing the rich over the super-rich, claims it is plausible that ‘when people reach a certain level, even if they are worse off than others, benefiting them does not, in itself, matter more’. If he is right, then there is some threshold after which considerations of priority no longer apply. Plausibly, such a threshold should be non-arbitrary. If so, what better candidate could there be than the neutral level of wellbeing?