In Chapter 17 of his magnificent Reasons and Persons, Derek Parfit asks what he describes as an ‘awesome question’: ‘How many people should there ever be?’ For a utilitarian like me, the answer seems simple: there should be however many people it takes to make the world best. Unfortunately, if I answer Parfit's awesome question in this way, I may sink myself in a quagmire of axiological confusion. In this paper, I first describe certain aspects of the quagmire. Then I (...) introduce and explain some of the elements of a novel axiological view – ‘justicism’. Justicism is derived from some ideas originally suggested by Franz Brentano. It was developed in an effort to solve certain other problems confronting utilitarianism – problems explicitly about justice. I think, however, that as a sort of happy by-product, justicism also generates a plausible answer to Parfit's awesome question. This may come as a bit of surprise, since justicism is a form of totalism, and it is widely thought that no totalistic theory can provide a satisfactory answer to Parfit's question. After presenting and explaining my proposed solution, I address some objections. (shrink)

Just because an angel is better than a stone, it does not follow that two angels are better than one angel and one stone. So said Aquinas (Summa contra Gentiles III, 71), and the sentiment was echoed by Leibniz. In section 118 of the Theodicy he wrote: "No substance is either absolutely precious or absolutely contemptible in the sight of God. It is certain that God attaches more importance to a man than to a lion, but I do not know (...) that we can bc sure that he prefers one man to an entire species of lions." Even Kant was bitten by this bug. In one of his pre-Critical works he was moved to say, à propos of lice, that even though they “may in our eyes be as worthless as you like, nevertheless it is of more consequence to Nature to conserve this species as a whole than to conserve a small number of members of a superior species." In these passages Aquinas, Leibniz, and Kant gave expression to a distinctive and interesting view about the value of animal species and animal populations. At its simplest, this is the view that there is a special value in the existence of animal species or in the existence of a wide variety of different animal species. But the view also goes deeper than this. An animal species, after all, is nothing over and above the individual animals which make it up, and the value which it contributes to the world must therefore be some function of the values contributed by those individual animals. At the deepest level, what the view expressed by Aquinas, Leibniz, and Kant holds is that the value which an individual animal contributes to thc world is not constant but varies with the number.. (shrink)

The long sweep of human history has involved a continuing interaction between peoples' efforts to improve their well-being and the environment's stability to sustain those efforts. Throughout most of that history, the interactions between human development and the environment have been relatively simple and local affairs. But the complexity and scale of those interactions are increasing. What were once local incidents of pollution shared throughout a common watershed or air basin now involve multile nations - witness the concerns for acid (...) desposition in Europe and North America. What were once acute episodes of relatively reversible damage now affect multiple generations - witness the debates over disposal of chemical and radioactive wastes. (shrink)

A principal aim of the branch of ethics called ‘population theory’ or ‘population ethics’ is to find a plausible welfarist axiology, capable of comparing total outcomes with respect to value. This has proved an exceedingly difficult task. In this paper I shall state and discuss two ‘trilemmas’, or choices between three unappealing alternatives, which the population ethicist must face. The first trilemma is not new. It originates with Derek Parfit's well-known ‘Mere Addition Paradox’, and was first explicitly stated by Yew-Kwang (...) Ng. I shall argue that one horn of this trilemma is less unattractive than Parfit and others have claimed. The second trilemma, which is a kind of mirror image of the first, appears hitherto to have gone unnoticed. Apart from attempting to resolve the two trilemmas, I shall suggest certain features which I believe a plausible welfarist axiology should possess. The details of this projected axiology will, however, be left open. (shrink)

Act Utilitarianisms divide into Total and Average versions. Total versions seem to imply Parfit’s “Repugnant Conclusion”. Average versions are proposed in part to avoid the Repugnant Conclusion, but these are subject to “Mere Addition” arguments as detailed by Hudson in “The Diminishing Marginal Value of Happy People”. Thus, various intermediate versions of utilitarianism, such as the one investigated by Hurka in “Value and Population Size”, take on interest. But Hudson argues that such compromise theories are subject to the mere addition (...) arguments, and are therefore no improvement over Average Utilitarianism. I disagree: some such compromise solutions escape Hudson’s Mere Addition arguments. (shrink)

Ascertaining the optimum global population raises not just substantive moral problems but also philosophical ones, too. In particular, serious problems arise for utilitarianism. For example, should one attempt to bring about the greatest total happiness or the highest level of average happiness? This article argues that neither approach on its own provides a satisfactory answer, and nor do rights-based or Rawlsian approaches, either. Instead, what is required is a multidimensional approach to moral questions—one which recognises the plurality of our values. (...) Such an approach can be formalised by employing multidimensional indifference-curves. Moreover, whereas classical utilitarianism might be thought to enjoin us to bring about a larger global population, a multidimensional approach clearly suggests a significant reduction in human numbers. (shrink)

Population ethics contains several principles that avoid the repugnant conclusion. These rules rank all possible alternatives, leaving no room for moral ambiguity. Building on a suggestion of Parfit, this paper characterizes principles that provide incomplete but ethically attractive rankings of alternatives with different population sizes. All of them rank same-number alternatives with generalized utilitarianism.

In a series of articles on population theory, culminating in his 1984 b00k Reasons and Persons, Dcrck Pariit presented dilemmas for utilitarian and conscqucntialist moral theories.] ParHt’s work has led to rcncwcd interest in thc theory of optimal population. More generally, Pariit is searching for a general theory of bcncHcencc—"Theory X"——that also will covcr population comparisons. Theory X corresponds to Kenneth Arrow’s notion of a social welfare function—both attempt t0 provide 21 generic formula or algorithm for ranking social outcomes on (...) the basis of their characteristics. (shrink)