This essay introduces a new type of measure of social welfare, where populations are evaluated by their resemblance to an optimum population, which is an (in principle) possible population with the highest degree of social welfare, relative to some circumstances. Here it is argued to be the largest possible population where everyone fares maximally well. The new measure is responsive to quality of welfare, equality of welfare, and the number of people. It satisfies dominance and negative monotonicity, and it avoids (...) both the repugnant conclusion and a reverse repugnant conclusion for comparisons relative to our future on earth. (shrink)

Advances in technology have made it possible for us to take actions that affect the numbers and identities of humans and other animals that will live in the future. Effective and inexpensive birth control, child allowances, genetic screening, safe abortion, in vitro fertilization, the education of young women, sterilization programs, environmental degradation and war all have these effects. Although it is true that a good deal of effort has been devoted to the practical side of population policy, moral theory has (...) not dealt adequately with the new possibilities. The dilemma faced by moral theory is that traditional theories cannot answer moral questions involving the creation of people. Two related problems arise. The first concerns numbers: how many people should there be? The second asks what sort of people should live and what their levels of well-being should be. Conventional social-contract theories, including the work of Rawls (1971), are restricted to situations with a fixed number of individuals. Sumner (1978) attempts to extend a Rawlsian veil-of-ignorance approach to possible people but is aware of the difficulties involved. The main problem is that possible people must be thought to benefit when they move from non-existence to existence, a view that we reject (see Section 1, Heyd, 1992, Chapter 1; McMahan, 1996a; Parfit, 1984, Appendix G). Rights-based and duty-based theories suffer from a similar problem; there must be a person who has the right or a person to whom the duty is owed (see McMahan, 1981). (shrink)

The book contains the first part of an investigation aimed at finding out why it is morally wrong to cause species to go extinct. That it is morally wrong seems to be a very basic and widely held intuition. It seems reasonable that a moral theory worth taking seriously ought to be able to account for that intuition. The most common attempt to answer our question is to refer to the instrumental value of the species for human beings – the (...) anthropocentric instrumental approach as I have chosen to call it. This is the answer that is discussed in this book. We have found many ways in which different species have instrumental value for human beings – both individually and as a part of ecosystems and of biodiversity in general. We could not guarantee however that this includes all species. In some cases, it also turned out that the instrumental value of the species in fact favours exploitation maybe even as far to the extinction of the species. We also noticed that there is no guarantee that the instrumental value of the species can always outweigh the competing values that we would gain by different encroachments that contribute to the extinction of the species. We found however that there are some special circumstances that help push the scale in the direction of preservation. I am thinking of some particular types of value such as choice value and transformation value – values that in general seem to favour preservation of species. This principle shows us that it would be rational from an anthropocentric instrumental vantage point to rule in favour of preservation in many of the cases where we are uncertain about the value of the species, about the best way of utilising the value, or about the connection between the species and other species or biodiversity in general. I am finally thinking of the moral principle that we have duties to consider the future interests of generations to come. We found that with a few exceptions it is justified to adopt such a principle. This in combination with the principles of precaution ought in general to urge us not to cause the extinction of species unless we have very trustworthy evidence that they will not turn out to be more valuable alive to future generations in comparison to what we can get from driving them to extinction. In relation to the discussion about the value of other species for human beings, it is worth noticing that all the arguments we have found in favour of preservation would be even stronger – and therefore account even better for the intuition that it is at least prima facie wrong to cause extinction – if we also accepted that other entities than human beings can have moral standing. Finally, we noticed that our moral intuitions strongly indicate that even in the cases where the instrumental value of other species for human beings talks in favour of preservation, there is still something lacking. Something we have to account for in order to totally account for our moral intuition against extinction. The conclusion will have to be that anthropocentric instrumentalism is in favour of preservation in many cases – probably in more cases than is generally acknowledged – but that it is not enough to give a complete account of the intuition that it is prima facie morally wrong to contribute to the extinction of species. We therefore have to continue our search for such an account. (shrink)

The aim of this investigation is to answer the question of why it is prima facie morally wrong to cause or contribute to the extinction of species. The first potential answer investigated in the book is that other species are instrumentally valuable for human beings. The results of this part of the investigation are that many species are instrumentally valuable for human beings but that not all species are equally valuable in all cases. The instrumental values of different species also (...) have to compete with other human values. Sometimes these other values probably outweigh the value of the continued existence of the species. In general the degree of uncertainty is very high and the precautionaty principle is recommended to deal with these uncertainties. We also found that we have a duty to consider the interests of future generations of human beings and that these duties, in general, speak in favour of preservation. Anthropocentric instrumentalism therefore provides us with rather strong reasons to consider many cases of human caused extinction as prima facie morally wrong. Even so, anthropocentric instrumentalism does not fully account for the moral intuition we set out to investigate. The next potential answer that is investigated in the book is that species have a moral standing in their own right. The result of this part of the investigation is that this idea is highly unlikely, in particular because species cannot have any interests to consider. Anotgher potential answer is that species have intrinsic value in some other meaning that does not imply moral standing. We concluded that it is possible to be subjectively valued as an end and that many species have properties that make them highly suitable for being valued as ends by human beings. Finally, we found that our contributions to the extinction of species in most cases frustrate the interests of many non-human sentient beings. This is true if the species in question is made up of sentient individuals, and it is also true when the species in question is made up of non-sentient individuals that have instrumental value for sentient individuals of other species. There are exceptions to this rule, but all in all it seems that the inclusion of non-human sentient individuals together with us humans as moral objects, in most cases, tip the scale drastically in favour of preservation. The main result of the investigation is that there is not one but several explanations to why it is prima facie morally wrong to contribute to the extinction of species – and all of them are about duties to respect the interests of individual sentient animals, including human beings. (shrink)