X OVERPOPULATION AND THE QUALITY OF LIFE D E R E K P A R F I T H o w many people should there be? Can there be overpopulation: too many people living? I shall present a puzzling argument about these questions, show how this argument can be strengthened, then sketch a possible reply.* I Q U A L I T Y A N D Q U A N T I T Y Consider the outcom es that might be produced, in some part o f the world, by two rates of population growth. Suppose that, if there is faster growth, there would later be more people, who would all be worse off. These outcomes are shown in Fig. i . The width of the Fig. i D erek Parfit, 'O verp op u latio n and the Q u ality o f L ife ' . © 1986 D erek Parfit. Printed by perm ission o f the author. * Th e first h alf o f this (hitherto unpublished) essay sum m arizes a longer discussion in m y Reasons and Persons (O xfo rd , 1984). Ih a ve been greatly helped by J. M cM ahan, J. R . R ichards, L . T em kin , K . K a lafsk i, and R . Jones. For further reading on this su b ject, see Obligations to Future Generations, ed. R . I. S ikora and B. B arry (Philadelphia, 1978) and M cM ahan's long review o f this anthology in Ethics 92, N o. 1, 1981. 146 DEREK PARFIT blocks shows the number o f people living; the height shows how well o ff these people are. Com pared with outcome A , outcom e B would have twice as many people, who would all be worse off. To avoid irrelevant complications, I assume that in each outcom e there would be no inequality: no one would be worse off than anyone else. I also assume that everyone's life would be well worth living. There are various ways in which, because there would be twice as many people in outcom e B , these people might be all worse off than the people in A . There might be worse housing, overcrowded schools, more pollution, less unspoilt countryside, few er opportuni ties, and a smaller share per person of various other kinds of resources. I shall say, for short, that in B there is a lower quality o f life. Except for the absence of inequality, these two outcomes could be the real alternatives for some country, or mankind, given two rates of population growth over many years. W ould one of these outcom es be worse than the other? I do not mean 'morally w orse' in the sense that applies only to agents and to acts. But one of two outcom es can be worse in another sense that has moral relevance. It would be worse, in this sense, if more people suffer, or die young. W ould it be worse, in this sense, if the outcome was B rather than A ? Part o f the answer is clear. W e would all agree that B would be, in one way, worse than A : it would be bad that everyone would be worse off. O n one view , this is all that matters, and it makes B worse than A . This view is expressed in The Average Principle: If other things are equal, it is better if people's lives go, on average, better. The Hedonistic version of this principle substitutes, for 'go better' , 'contain more happiness' .1 1 O f the m any econom ists w ho appeal to the A v e ra g e Principle, som e m ake it true by definition. S ee , for exam p le, P. A . Sam uelson, E conom ics (N ew Y o rk , 1970), p. 551. Certain w riters state this principle so that it covers only the lives that are, at any tim e, being lived. This m akes the principle im ply that it would have been better if all but the best-off p eople had just dropped dead. M y versions o f the A v erag e Principle do not im ply this absurd conclusion. If anyone with a life w orth living dies earlier, this causes p eop le 's lives to g o , on average, w orse, and to contain a sm aller average sum o f happiness. O n the other main view about this question, it is good if any extra life is lived, that is worth living. O n this view B might be better than A . B would be in one way worse, because everyone would be worse off. But in another way B would be better, because there would be m ore people living, all o f whose lives would be worth living. A nd the fact that people would be worse o ff might be less important than- or outweighed by- the fact that there would be m ore people living. W hich o f these views should we accept? Could a loss in the quality o f people's lives be outweighed by a sufficient increase in the quantity o f worthwhile life lived? If this is so, what are the relative values of quality and quantity? These are the central questions about overpopulation.2 The A verage Principle implies that only quality matters. A t the other extreme is The Hedonistic Total Principle: If other things are equal, it is better if there is a greater total sum of happiness. This principle implies that only quantity matters. Its Non-Hedonistic version substitutes, for 'happiness' , 'whatever makes life worth living' . O n the Hedonistic Total Principle, B would be better than A because each life in B would be more than half as happy as each life in A . Though the people in B would each be less happy than the people in A , they together would have more happiness- just as two bottles more than half-full hold more than a bottleful. O n the nonH edonistic version o f this principle, B would be better than A because, com pared with lives in A , lives in B would be more than ha lf as much worth living. These claims may seem implausibly precise. But lives in B would be more than half as much worth living if, though a m ove from the level in A to that in B would be a decline in the quality o f life, it would take much more than another similarly large decline before 2 T h ese rem arks assum e that the quality o f life is higher if p e o p le 's lives go better, and that each life goes better i f it contains a greater quantity either o f happiness or o f w h atever else m akes life w orth living. 'Q u ality ' thus m eans 'quantity, p er life lived ' . In Section 5 b elow I drop this assum ption, thereby sim plifying the contrast betw een qu ality and quantity. (If this note is puzzling, ignore it.) OVERPOPULATION AND THE QUALITY OF LIFE 147 148 DEREK PARFIT people's lives ceased to be worth living. There are many actual cases in which such a claim would be true.3 2 T H E R E P U G N A N T C O N C L U S I O N Consider Fig. 2. O n the Total Principle, just as B would be better than A , C would be better than B , D better than C , and so on. Best o f all would be Z . This is an enormous population all of whom have lives that are not much above the level where they would cease to be worth living. A life could be like this either because its ecstasies make its agonies seem just worth enduring, or because it is painless but drab. Let us imagine lives in Z to be of this second kind. There is nothing bad in each o f these lives; but there is little happiness, and little else that is good. The people in Z never suffer; but all they have is muzak and potatoes. Though there is little happiness in each life in Z , because there are so many of these lives Z is the outcom e in which there would be the greatest total sum o f happiness. Similarly, Z is the outcom e in which there would be the greatest quantity of whatever makes life worth living. (The greatest mass of milk might be in a vast heap of bottles each containing only one drop.) It is worth comparing Z with N ozick's imagined Utility Monster. F ig . 2 3 In w hat follow s I assum e, for convenience, that there can be precise differences betw een the quality o f life o f d ifferent groups. I b elieve that there could not really be such precise d ifferences. A ll that my argum ents require is that som e people can be w orse o ff than others, in m orally significant w ays, and by m ore or less. This is som eone who would gain more happiness than we would lose whenever he is given any o f our resources. Some Utilitarians believe that the Hedonistic Total Principle should be our only moral principle. N ozick claims that, on this Utilitarian theory, it would be best if all our resources were taken away and given to his U tility M onster, since this would produce the greatest total sum of happi ness. A s he writes, 'unacceptably, the theory seems to require that we all be sacrificed in the m onster's m aw' .4 H ow could it be true that, if all mankind's resources were given to N ozick's M onster, this would produce the greatest total sum of happiness? For this to be true, this M onster's life must, compared with other people's lives, be millions o f times as much worth living. W e cannot imagine, even in the dimmest way, what such a life would be like. N ozick's appeal to his M onster is therefore not a good objection to the Total Principle. W e cannot test a moral principle by applying it to a case which we cannot even imagine. Return now to the population in outcom e Z . This is another U tility Monster. The difference is that the greater sum of happiness would come from a vast increase, not in the quality o f one person's life, but in the number o f lives lived. A nd this U tility M onster can be imagined. W e can imagine what it would be for som eone's life to be barely worth living- containing only muzak and potatoes. A nd we can imagine what it would be for there to be many people with such lives. In order to imagine Z , we m erely have to imagine that there w ould be very many. W e could not in practice face a choice between A and Z . Given the limits to the w orld's resources, we could not in fact produce the greatest possible sum of happiness, or the greatest amount of w hatever makes life worth living, by producing an enormous population whose lives were barely worth living.5 But this would be 4 R . N o zick , Anarchy, State, and Utopia (O x fo rd , 1974), p. 41. 5 A cco rd in g to som e versions o f the w idely assum ed Law o f D im inishing Marginal Utility, w e could do this. T h e point can be m ade m ost easily in H edonistic terms. It is assum ed that, because resources produce m ore happiness if they are given to p eople w ho are w orse o ff, th ey w ould produce m ost happiness if they are all given to p eople w hose lives are barely w orth living. Th ere is here an obvious oversight. M any resources are needed to m ake each person 's life even reach a level w here it begins to be w orth living. Such resources do not help to produce the greatest possible quantity o f happiness, since they are m erely b eing used to raise people to the level w here their happiness begins to outw eigh their suffering. OVERPOPULATION AND THE QUALITY OF LIFE 149 150 DEREK PARFIT m erely technically impossible. In order to suppose it possible, we m erely need to add some assumptions about the nature and availability o f resources. W e can therefore test our moral principles by applying them to A and Z .6 The Total Principle implies that Z would be better than A . M ore generally, the principle implies The Repugnant Conclusion: Com pared with the existence of very many people- say, ten billion- all o f whom have a very high quality o f life, there must be some much larger number of people whose existence, if other things are equal, would be better, even though these people would have lives that are barely worth living.7 A s its name suggests, most o f us find this conclusion hard to accept. M ost o f us believe that Z would be much worse than A . T o keep this belief, we must reject the Total Principle. W e must also reject the broader view that any loss in the quality o f life could be outweighed by a sufficient increase in the total quantity of whatever makes life worth living. Unless we reject this view , we cannot avoid the Repugnant Conclusion. W hen the stakes are low er, as in the comparison between A and B , most of us believe that B would be worse. W e believe that, com pared with the existence of ten billion people whose lives are very well worth living, it would be worse if instead there were twice 6 It m ay help to give this illustration. Suppose that, as a Negative Utilitarian, I b elieve that all that m atters m orally is the re lief or prevention o f suffering. It is pointed out to me that, on m y view , it w ould be best if all life on Earth w as painlessly d estroyed, since on ly this w ould ensure that there w ould be no m ore suffering. A n d suppose I agreed that this w ould be a very bad outcom e. C o uld I say: ' It is true that this very bad outcom e w ould , according to m y m oral view , be the best outcom e. B ut this is no o b jectio n to m y v iew , since w e are not in fact able to bring about this o u tco m e' ? Th is w ould be no d efence. O n my view , I ought to regret our inability to bring about this outcom e. W heth er my view is plausible cannot depend on what is technically possible. Since this view im plies that the destruction o f all life on Earth w ould be the best ou tcom e, if I firm ly believe that this outcom e w ould be very bad, I should reject this view . 7 T h e phrase ' if o th er things are equal' allow s for the possibility that the existence o f the larger population m ight, in som e oth er w ay, be w orse. It m ight, for instance, in vo lve injustice. W hat the R epugnant Conclusion claims is that, though the low er quality o f life w ould m ake Z in one w ay w orse than A , this bad feature could be less im portant than, or be outw eighed by, Z 's good feature: the existence o f enough extra people w hose lives are- even if on ly barely- w orth living. as many people who were all worse off. T o keep this belief, we must again reject the Total Principle. Suppose that we do reject this principle. U nfortunately, this is not enough. A s I shall now argue, it is hard to defend the belief that B would be worse than A , and it is also hard to avoid the Repugnant Conclusion. 3 T H E M E R E A D D I T I O N P A R A D O X Consider the alternatives shown in Fig. 3. There is here a new outcom e, A + . This differs from A only by the addition of an extra group of people, whose lives are well worth living, though they are worse o ff than the original group. The inequality in A + is natural, not the result o f any kind of social injustice. Take my waves to show the A tlantic Ocean, and assume that we are considering possible outcom es in some past century, before the A tlantic had been crossed. In A + there was one group of people living in E urope, A sia , and A frica, and another group, who w ere worse off, living in the Am ericas. A is a different possible outcom e at this time, in which the Am ericas were uninhabited. Perhaps the Bering Straits had opened before the land was crossed. Is A + worse than A ? Note that I am not asking whether it is better. If we do not believe that the existence of extra people is in itself good, we shall deny that the extra group in A + makes A + better than A . But is A + worse than A ? W ould it have been better if OVERPOPULATION AND THE QUALITY OF LIFE 151 Fig3 152 DEREK PARFIT the extra group had never existed? This is hard to believe. It may seem a bad feature that there is natural inequality in AH- that the extra group are, through no fault o f theirs, worse off than the original group. But the inequality in A + does not seem to justify the view that the extra group should never have existed. W hy are they such a blot on the Universe? Y o u may think that you have no view about whether it would have been better if the extra group had never existed. It may help to consider another outcome: A + Hell. In this outcom e the extra group are innocent people who all have lives which are much worse than nothing. They would all kill themselves if they could, but their torturers prevent this. W e would all agree that A + Hell is worse than A . It would have been better if this extra group, as they all passionately wish, had never existed. Since we believe that A + Hell is worse than A , we must be able to compare A + and A . U nlike the extra group in H ell, the extra people in A + have lives that are well worth living; and their existence is not bad for anyone. Most o f us could not honestly claim to believe that it would have been better if these people had never existed. Most of us would therefore believe that A + is not worse than A . Now suppose that, as a result of changes in the environment, A + turned into D ivided B. In both these outcom es the same number of people would exist, so we are not making one of the unfamiliar comparisons which involve different numbers of people in existence. Since the numbers are the same in A + and Divided B, our ordinary moral principles apply. O n the principles which most of us accept, D ivided B would be better than A + . On the Principle of Utility it is better if there is a greater net sum o f benefits- a greater sum of benefits minus losses. D ivided B would be better than A + in utilitarian terms, since the benefits to the people who gain would be greater than the losses to the people who lose. On the Principle o f Equality it is better if there is less inequality between different people. D ivided B would be better than A + in egalitarian terms, since the benefits would all go to the people who are worse off. It might be objected that the Principle o f Equality does not apply to people who cannot even communicate. But suppose that I know about two such people, one of whom is, through mere bad luck, worse off. Call these people Poor and Rich. I could either benefit R ich, or give a greater benefit to Poor. M ost of us would believe that it would be better if I do the second. A nd we would believe that this would make the outcom e better, not only because I would give Poor a greater benefit, but also because he is worse off than Rich. Most of us would believe this even though Poor and Rich cannot (except through me) communicate. How could we deny that a change from A + to D ivided B would be a change for the better? W e would have to claim that the loss to the best-off people in A + matters more than the greater gain to the equally numerous worst-off people. This seems to commit us to the Elitist view that what matters most is the condition of the best-off people. This is the opposite o f R aw ls's famous view that what matters most is the condition o f the worst-off people.8 Most o f us would reject this Elitist V iew . Most of us would therefore agree that D ivided B would be better than A + . Suppose finally that the Atlantic is crossed, turning Divided B into B . These two outcom es are clearly equally good . Since Divided B would be better than A + , B must be better than A + . Let us now combine the conclusions we have reached. Most of us believe both that A + is not worse than A , and that B is better than A + . These beliefs together imply that B is not worse than A . B cannot be worse than A if it is better than something- AH- which is not worse than A . In the same way, you cannot be taller than me if you are shorter than som eone who is not taller than me. But, as I earlier claim ed, most of us also believe that B is worse than A . W e therefore have three beliefs which are inconsistent, and imply a contradiction. These beliefs imply that B both is and is not worse than A . I call this the Mere Addition Paradox. This is not just a conflict between different moral principles. Suppose that we accept both the Principle of Equality and the Principle o f Utility. There can be cases where these principles conflict- where greater equality would reduce the sum of benefits. But such a case does not reveal any inconsistency in our moral view. W e would m erely have to ask whether, given the details o f the case, the gain in equality would be more important than the loss of OVERPOPULATION AND THE QUALITY OF LIFE 153 8 J. R aw ls, A Theory o f Justice (C am b rid ge, M ass., 1971). 154 DEREK PARFIT benefits. W e would here be trying to decide what, after considering all the details, we believe would be the better outcome. In the M ere Addition Paradox, things are different. Most o f us here believe, all things considered, that B is worse than A , though B is better than A + , which is not worse than A . If we continue to hold these three beliefs, we must conclude that B both is and is not worse than A . But we cannot possibly accept this conclusion, any more than we could accept that you both are and are not taller than me. Since we cannot possibly accept what these three beliefs imply, at least one belief must go. W hich should go? Suppose that we keep our belief that B is better than A + , because we cannot persuade ourselves that what matters most is the condition o f the best-off people. Suppose that we also keep our belief that A + is not worse than A , because we cannot persuade ourselves that it would have been better if the extra group had never existed. W e must then reject our belief that B is worse than A . W e must conclude that, if these were two possible futures for some society or the world, it would not be worse if what comes about is B: twice the population, who are all worse off. The M ere Addition Paradox does not force us to this conclusion. W e can avoid the conclusion if we reject one of our other two beliefs. Some people reject the belief that A + is not worse than A , because they think that the inequality in A + is enough to m ake A + worse. These people can keep their belief that B is worse than A . N ote, how ever, that we cannot simply claim that A + must be worse than A , since it is worse than something- B- which is worse than A . W e would here be rejecting one o f our three inconsistent beliefs simply on the ground that it is not consistent with the other two. This could be said against each belief. To avoid the paradox we must believe, without considering the rest o f the argument, that A 4is worse than A . W e must believe that it was bad in itself that the extra people ever lived, even though these people had lives that were well worth living, and their existence was bad for no one. T o the extent that we find this hard to believe, we still face a paradox. It may be objected: 'Y ou r argument involves a kind of trick. W hen you compare A and A + , you claim that the extra group's existence was bad for no one. But by the time we have moved to B the original group have becom e worse off. The addition of the extra group was bad for the original group.' T he argument can be restated. Suppose that A + was the actual state o f the world in some past century. A is a different state of the world which was m erely possible. W e can ask, 'W ould A have been better? W ould it have been better if the worse-off group had never existed?' A s I have said, most of us could not answer Y es. Suppose next that A + did not in fact later change into either D ivided B or B . W e can ask, 7/ this change had occurred, would it have been a change for the better?' It is hard to answer No. On this version of the argument, the last objection has been met. The better-off group in A + was not an originally existing group, to which the worse-off group was added. A nd the existence o f the worse-off group was not bad for the better-off group. It is worth giving another version of the argument. To ensure that there was no social injustice, we assumed that the two groups in A + did not know of each other's existence. W e could assume instead that both these groups live in the same society, and that the people in one group are worse off, not because of social injustice, but because they all have some handicap which cannot be cured. Suppose, for exam ple, that they are deaf. If this is so, would it have been better if these people had never existed? W ould this have been better even though these people's lives are worth living, their existence is not bad for anyone, and if they had never existed no one else would have existed in their place? It is hard to believe that these deaf people should never have existed. On this version o f the argument, it again seems that A + is not worse than A . Suppose next that these deaf people could be cured, at some lesser cost to the other group. This would be like the change from A + to B. It is again hard to deny that this change would make the outcom e better. In this version of the argument, with the groups in one society, we seem again driven to conclude that, since B would be better than A + , which is not worse than A , B cannot be worse than A . There are some other possible objections to this argument. But rather than discussing these I shall turn to another argument. This is harder to answer, and it also leads to the Repugnant Conclusion. OVERPOPULATION AND THE QUALITY OF LIFE I55 156 DEREK PARFIT 4 T H E S E C O N D P A R A D O X Consider the first three outcom es shown in Fig. 4. Though this argument involves many outcom es, we need to make only two comparisons. O ne is between A + and the much more populated A lpha. Suppose that A lpha will be the actual outcome at some time far in the future, after humans have colonized thousands of planets in this G alaxy. A + is a different possible outcome at this time, in which humans have colonized only one other planet, near a distant star. A s before, in neither A lpha nor A + would the inequality between different people be the result o f social injustice. Because of the difficulties o f trans-Galactic travel, those who are better o ff could not raise the quality o f life o f those who are worse off. The comparison between A + and A lpha replaces the com pari son, in the old argument, between A and A + . On one view, the natural inequality in A + m akes it worse than A . If I held this view , I would now say: The inequality in A lpha is in one way worse than the inequality in A + , since the gap between the better-off and worse-off people is slightly greater. But in another way the inequality is less bad. This is a matter o f the relative numbers of, or the ratio between, those who are better-off and those who are worse-off. H alf o f the people in A + are better o ff than the other half. This is a worse inequality than a situation in which almost everyone is equally well off, and those who are better off are only a fraction of one per cent. A nd this is the difference between A + and A lpha. Because there are so many groups at level 45 (most of them not shown in the diagram ), the better-off people in A lpha are only a fraction of one per cent. To put these claims together: The inequality in A lpha is in one way slightly worse than the inequality in A + , but in another way much better. There is a slightly greater gap between the better-off and w orse-off groups, but a much better ratio between these groups. A ll things considered, the natural inequality in A lpha is not worse than the natural inequality in A + . 9 9 If y ou b elieve that the inequality is w orse in A lp h a than it is in A + , read (when you reach it) footn ote 11. 105 A lp h a n45 and so on 104 Beta 45 and so on 95 40 A lp h a 2 so on O m ega 2- O m eg a 394 ,40 Beta 2 and 103 45 „ and G am m a so on 93 40 G am m a 2 and so on ----145 O m e g a - - - .8 0 ----140 O m e g a 2 -------1 90 O m e g a 100 158 DEREK PARFIT It may be objected that A lpha is worse than A + because the worst-off groups in A lpha are worse o ff than the worst-off group in A + . M any people accept R aw ls's view that what matters most is the condition o f the worst-off group. But there are two quite different ways in which any worst-off group might have been better off. This group might have existed, and been better off. This is the ordinary case, which Rawls discusses. Things would have been quite diffe rent if the worst-off group had never existed. This would have provided another sense in which the 'w orst-off' group would have been better o ff, since some other group would then have been those who are worst off. W ould this have made the outcome better? If we answer Y es, we must agree that it would have been even better if the second worst-off group had also never existed, and the third worsto ff group, and the fourth worst-off group, and so on. It would have been best if everyone except the best-off group had never existed. Similarly, it might be best if in future only the best-off nation- such as the Norwegians- have children. Even if this would be worse for them, it might cause it to be true that, after the rest o f us have died, the 'w orst-off' people in the world are as well o ff as possible. This way of raising the level o f 'the worst-off group' has no moral merit. The non-existence of all but the best-off group would not, in the morally relevant sense, make the worst-off group better off. The inequality in A lpha is not worse than the inequality in A + ; nor is A lpha worse than A + because the worst-off groups are worse off. Nor is there any other way in which A lpha is worse than A + . 10 A n d , in one w ay, A lpha is better than A + . A lpha does not differ from A + m erely by involving the existence o f the very many groups at level 45. A ll o f the people in A + are in one of two groups, and both these groups are, in A lpha, better off. (These are the groups at level 105.) I conclude that, since A lpha is in this way better than 10 A lp h a is w orse than A + according to the A v e ra g e Principle. B u t this is one o f the cases w hich show that w e should reject this principle. T h e A v e ra g e Principle could also im ply that it w ould be best if in future all excep t the N orw egians have no children. For further objection s to this principle, see my Reasons and Persons, Section 143, and J. A . M cM ahan , 'Problem s o f Population T h e o ry ' , E thics, V o l. 92 no. 1, O ct. 1981. It m ay also be claim ed. 'A lp h a is w orse than A + because, if w e had to choose in which outcom e we w ould prefer to exist- w ithout know ing w ho we w ould be- it w ould be rational to choose A + . ' For objections to this claim , see my Reasons and Persons, Section 133. OVERPOPULATION AND THE QUALITY OF LIFE 159 A + , and is in no way worse, A lpha is better than A + . W e are assuming that the actual outcom e at some future time is A lpha. If the outcom e had been A + , this would have been worse. Could we honestly deny this conclusion? Could we honestly claim that A f would not have been worse than Alpha? This is the claim that it would not have been worse if the worst-off people in Alpha had never existed, even though their lives are worth living, and if they had never existed, so that the outcom e had been A + , the inequality would have been no better, and everyone who did exist would have been worse off. That this would not have been worse is hard to b elieve .11 Consider next whether Beta would be better than Alpha. In a change from A lpha to B eta, the best-off group in A lpha would lose a little, but an equally large worse-off group would gain very much more. If this is all we know about this change, it would need extreme Elitism to deny that it would be a change for the better. The rest o f the argument merely involves repetition. Gam ma would be better than Beta in the same way in which Beta would be better than A lpha. D elta would be better than Gam m a in the same w ay, Epsilon better than D elta, and so on down to Om ega. W e then run through the argument again, on the second line of the diagram, from O m ega to O m ega 2. (O m ega is thinner on this second line only because, to make room , all widths are reduced.) Similar steps take us to O m ega 3, O m ega 4, and all the way to Om ega 100. Every step would be a change for the better, so O m ega 100 must be the best o f all these outcomes. Since this argument implies that Om ega 100 would be better than A + , it leads us to the Repugnant Conclusion. A-lmight be a world with ten billion people, o f whom even the worse-off half have an extremely high quality o f life. According to this argument it would be better if instead there were vastly many more people, all o f whose lives were barely worth living. W hat is wrong with this argument? To avoid its conclusion, we must either deny that A + would have been worse than A lpha, or 11 Suppose you b elieve that the inequality in A lp h a is w orse than the inequality in A + . Is this enough to justify the claim that it w ould not have been w orse if the actual o u tcom e had been A + rather than A lp h a ? W hich w ould have m attered m ore: (1) that the inequality w ould have been less bad, or (2) that everyo ne w ho did exist w ou ld have been w orse o ff? It is hard to deny that (2) w ould have m attered m ore. i6o DEREK PARFIT deny that Beta would be better than A lpha. Unless we deny one of these claims, we cannot plausibly deny the similar claims which carry us down to Om ega 100. But how can we deny that A + would have been worse than Alpha? If the outcome had been A + , everyone who existed would have been worse off. A nd how can we deny that Beta would be better than Alpha? In a change to Beta some people would lose a little, but as many people who are much worse off would gain much more. W hile we consider these outcom es in these simple terms, it is hard to answer this argument. There is little room for manoeuvre. To find an answer we must consider other features of these outcom es.12 5 T H E Q U A L I T Y O F S I N G L E L I V E S Consider first the analogue, within one life, o f the Repugnant C onclusion.13 Suppose that I can choose between two futures. I could live for another 100 years, all o f an extremely high quality. Call this the Century o f Ecstasy. I could instead live for ever, with a life that would always be barely worth living. Though there would be nothing bad in this life, the only good things would be muzak and potatoes. Call this the Drab Eternity. I believe that, o f these two, the Century o f Ecstasy would give me a better future. A nd this is the future that I would prefer. Many people would have the same belief, and preference. On one view about what makes our lives go best, we would be making a mistake. On this view, though the Century of Ecstasy 12 It m ay be o b jected that m y argum ent is like w hat are called Sorites Argum ents, w hich are know n to lead to false conclusions. Suppose w e assume that rem oving any single grain o f sand cannot turn a heap o f sand into som ething that is not a heap. It can then be argued that, even if w e rem ove every single grain, we must still have a h eap. O r suppose w e assume that the loss o f any single hair cannot cause som eone w h o is not bald to be bald. T h ere is a sim ilar argum ent for the conclusion that, even if som eone loses all his hair, this cannot m ake him bald. If m y argum ent was like this, it could be referred to those w ho w ork on what is w rong with Sorites A rgum en ts. But m y argum ent is not like this. A Sorites A rgum en t appeals to a series o f steps, each o f w hich is assum ed to m ake no difference. M y argum ent w ould be like this if it claim ed that A lp h a is not worse than A + , B eta is not w orse than A lp h a , G am m a is not w orse than B eta , and so on. But the argum ent claim s that A lp h a is better than A + , B eta is b etter than A lp h a , G am m a is b etter than B eta , and so on. T h e objections to Sorites A rgum en ts are therefore irrelevant. 13 This section is partly based on an unpublished paper by J. M cM ahan. would have great value for m e, this value would be finite, or have an upper limit. In contrast, since each day in the Drab Eternity would have the same small value for me, there would be no limit to the total value for me o f this second life. This value must, in the end, be greater than the limited value of the Century of Ecstasy. I reject this view. I claim that, though each day of the Drab Eternity would be worth living, the Century of Ecstasy would give me a better life. This is like M ill's claim about the 'difference in quality' between human and pig-like pleasures.14 It is often said that M ill's 'higher pleasures' are m erely greater pleasures: pleasures with more value. A s Sidgwick wrote, 'all qualitative comparison of pleasures must really resolve itself in quantitative [comparison]' .15 This would be so if the value o f all pleasures lay on the same scale. But this is what I have just denied. The Century of Ecstasy would be better for me in an essentially qualitative way. Though each day of the D rab Eternity would have some value for me, no amount of this value could be as good for me as the Century of Ecstasy. 6 P E R F E C T I O N I S M Return to the argument about overpopulation. Should we make a similar claim, not about the value for one person of different possible futures, but about the relative goodness o f different out com es? Cardinal Newman made such a claim about pain and sin. He believed that both of these were bad, but that no amount of pain could be as bad as the least amount o f sin. He therefore wrote that, 'if all mankind suffered extremest agony, this would be less bad than if one venial sin was com mitted' .16 Can we make such a claim about what is good in my outcom es A and Z ? Consider what I shall call the best things in life. These are the best kinds of creative activity and aesthetic experience, the best relation ships between different people, and the other things which do most to m ake life worth living. Return next to A and B. Suppose that all o f the best things in life are, in B, better. The people in B are all 14 J .S . M ill, Utilitarianism (L on d on , 1863), C h ap ter II. 15 H . Sidgw ick, The M ethods o f Ethics (Lon d on , 1907), p. 94. 16 J .H . N ew m an , Certain Difficulties Felt by Anglicans in Catholic Teaching (L o n d o n . 1885), V o l. I, p. 204. OVERPOPULATION AND THE QUALITY OF LIFE l6l DEREK PARFIT worse off than the people in A only because they each have many few er of these things. In B , for exam ple, people can hear good music only a few times in their lives; in A they can often hear music that is nearly as good. If this was the difference between A and B , I would cease to believe that B would be worse. A similar claim applies to the Repugnant Conclusion. W hy is it so hard to believe that my imagined world Z - or O m ega 100- would be better than a world of ten billion people, all o f whom have an extrem ely high quality o f life? This is hard to believe because in Z two things are true: people's lives are barely worth living, and most o f the good things in life are lost. Suppose that only the first o f these was true. Suppose that, in Z , all o f the best things in life remain. People's lives are barely worth living because these best things are so thinly spread. The people in Z do each, once in their lives, have or engage in one o f the best experiences or activities. But all the rest is muzak and potatoes. If this is what Z involves, it is still hard to believe that Z would be better than a world of ten billion people, each of whose lives is very well worth living. But, if Z retains all o f the best things in life, this belief is less repugnant. Now restore the assumption that in Z , and Om ega 100, most of the good things in life are lost. There is only muzak and potatoes. By appealing to the value of the best things in life, we can try to answer the argument. The argument involves two kinds of step. O ne is the claim that A lpha is better than A + , A lpha 2 is better than O m ega, and similar later claims. A + contains two groups of people, all o f whom are better o ff in A lpha. W e can add the assumption that these people are better o ff because, in A lpha, the best things in life are even better. A ppealing to the value of these best things cannot help us to reject the claim that A lpha is better than A + . A n d, as I argued, there seems to be no other way to reject this claim. If the actual outcom e had been A + , the inequality would have been no better, and everyone who existed would have been worse off. How can we deny that this would have been worse? There seems to be little hope of answering these steps in the argument. The other steps are all redistributive. In each step the best-off people would lose a little, but an equally large worse-off group would gain much more. Can we claim that at least one o f these steps would not be a change for the better? This cannot be plausibly claimed if what we appeal to is the Elitist V iew . W e cannot plausibly claim that it is the best-off people whose condition matters most. W hat we might appeal to is not Elitism, but Perfectionism. In the move from A lpha to O m ega 100, the best things in life must have disappeared. Suppose for instance that, in the move from A lpha to B eta, M ozart's music would be lost, in the move to Gam m a, H aydn's. In the move to D elta, Venice would be destroyed, in the m ove to Epsilon. V ero n a .17 W e might claim that, even if some change brings a great net benefit to those who are affected, it is a change for the worse if it involves the loss of one of the best things in life. W hen should we make this claim? It would not be plausible when we are considering outcom es that are close to O m ega 100. Suppose that, in one such outcom e, the best thing left is a bad performance of R ave l's Bolero; in the next outcom e, it is an even worse perform ance of R avel's B olero. W e cannot claim that great benefits to those who are worst-off would not make the outcom e better if they involved the loss of a bad performance o f R avel's Bolero. If such a claim is to have any plausibility, it must be made at the start. W e must reject the change in which the music of M ozart is lost. Has such a claim any plausibility? I believe that it has. It expresses one of our two main reasons for wanting to avoid the Repugnant Conclusion. W hen we are most concerned about overpopulation, our concern is only partly about the value that each life will have for the person whose life it is. W e are also concerned about the disappearance from the world of the kinds of experience and activity which do most to make life worth living. Perfectionism faces many objections. O ne is raised by the moral importance of relieving or preventing great suffering. W e should reject the Nietzschean view that the prevention of great suffering can be ranked wholly below the preservation o f creation o f the best things in life. W hat should Perfectionists claim about great 17 If, in the m ove from A lp h a to B eta , the b est-o ff people lose M o zart, it m ay seem that their quality o f life cannot, as m y argum ent assum es, fall by only a little. B u t I have exp lained how this m ight be so. T h e loss o f a few perform ances o f M ozart could fo r these p eople be nearly outw eighed by m any extra perform ances o f H aydn. OVERPOPULATION AND THE QUALITY OF LIFE 163 164 DEREK PARFIT suffering? But this problem is irrelevant here, since we can assume that in the various outcom es we are considering there would be no such suffering. A nother problem is raised by the fact that the good things in life do not come in quite different categories. It is because pain and sin are in such different categories that Newman believed sin to be infinitely worse. If we m erely compare Mozart and m uzak, these two may also seem to be in quite different categories. But there is a fairly smooth continuum between these two. Though Haydn is not as good as M ozart, he is very good. A nd there is other music which is not far below H aydn's, other music not far below this, and so on. Similar claims apply to the other best experiences, activities, and personal relationships, and to the other things which give most to the value of life . Most of these things are on fairly smooth continua, ranging from the best to the least good. Since this is so, it may be hard to defend the view that what is best has more value- or does m ore to make the outcom e better- than any amount of what is nearly as good. This view conflicts with the preferences that most of us would have about our own futures. But, unless we can defend this view , any loss of quality could be outweighed by a sufficient gain in the quantity o f lesser goods. These are only two o f the objections facing this view. It seems to m e, at times, crazy. But at least, unlike the Elitist V iew , it is not morally monstrous. A nd without Perfectionism how can we avoid the Repugnant Conclusion?18 18 I w ould be grateful for any com m ents on this essay, which could be sent to me at A ll Souls C o lle g e , O xford .