John Broome

This chapter considers whether the neutral level for extending life is a constant. It shows there are plausible grounds for thinking it may not be. However, it adopts the assumptions that it is constant as a default view. This leads to the standardized total principle for lives, which says that the value of a life is the total of temporal wellbeing contained in the life. This amounts to intrapersonal utilitarianism. The chapter considers the implication of this conclusion for the badness of death.

This chapter demonstrates how the assumptions made so far in the book imply that there is a single neutral level for existence. That is, there is a single level of wellbeing such that adding a person at that level is neither better nor worse than not adding her. It explains how this conclusion conflicts strongly with an intuition shared by many people: the ‘neutrality intuition’ that adding a person to the world’s population is generally ethically neutral. It uses examples such as the mere addition paradox. It outlines various ways in which the conflict with intuition might be circumvented.

This chapter starts to consider how wellbeing can be aggregated across a distribution. It describes two possible route to aggregation, called ‘the people route’ and the ‘snapshot route’. Each relies on a particular assumption of separability, which the chapter explains. The chapter examines the credibility of separability of times. It shows how separability of times conflicts with the value of longevity, and concludes that this principle cannot be relied on. It therefore rejects the snapshot route to aggregation.

This chapter distinguishes a notion of separability of lives from a stronger notion of separability of people, which takes into account the possibility of a person’s nonexistence. It defends separability of lives on the basis of the principle of personal good. It thereby opens up the people route to aggregation when the population of the world is constant. It assesses the principle of personal good, particularly considering its relation to the value of equality and its conflict with discounting for time.

This chapter opens the question of aggregating wellbeing across time to determine the value of a single person’s life. It explains the imperfect analogy between this sort of aggregation and aggregation across time to determine the overall value of a world. It assesses the principle of temporal good, the analogue of the principle of personal good. It shows there are plausible grounds for doubting the principle, which derive from various putative pattern goods. Nevertheless, this chapter eventually adopts the principle of temporal good as a default position. From this default position, it derives a same-lifetime addition theorem, which says that wellbeing is aggregated within a life additively.

This chapter considers how far what one ought to do when facing a decision of life and death is determined by the goodness of the distribution that will result. It defines, examines and assesses the principles of teleology and consequentialism in ethics. It compares normative theory with axiology. It considers how far a person’s lifetime wellbeing depends on all the wellbeing that comes to the person at times within her life, and how far the goodness of the world depends on the wellbeing of the people. It introduces the idea of pattern goods such as equality and longevity.

Practical reasoning is a process of reasoning that concludes in an intention. One example is reasoning from intending an end to intending what you believe is a necessary means: 'I will leave the next buoy to port; in order to do that I must tack; so I'll tack', where the first and third sentences express intentions and the second sentence a belief. This sort of practical reasoning is supported by a valid logical derivation, and therefore seems uncontrovertible. A more contentious example is normative practical reasoning of the form 'I ought to φ, so I'll φ', where 'I ought to φ' expresses a normative belief and 'I'll φ' an intention. This has at least some characteristics of reasoning, but there are also grounds for doubting that it is genuine reasoning. One objection is that it seems inappropriate to derive an intention to φ from a belief that you ought to φ, rather than a belief that you ought to intend to φ. Another is that you may not be able to go through this putative process of reasoning, and this inability might disqualify it from being reasoning. A third objection is that it violates the Humean doctrine that reason alone cannot motivate any action of the will. This paper investigates these objections

This chapter defines the neutral value for extending life. This is the level of a person’s temporal wellbeing at which it is just worth the person’s continuing to live: extending the life is equally as good for the person as not extending it. The chapter examines and rejects the view that extending a person’s life is normally ethically neutral. This view is analogous to the neutrality intuition about adding a person to the population. It implies that every level of wellbeing is neutral. It may be attributed to Epicurus, who argues that death generally does not harm the person who dies. The chapter considers Epicurus’ arguments.

This chapter surveys some of the issues that arise in policy making when the wellbeing of future generations must be taken into account. It analyses the discounting of future wellbeing, and considers whether it is permissible. It argues that the effects of policy on the number of future people should not be ignored, and it considers what is an appropriate basis for setting a value on these effects. It considers the implications of the non-identity effect for intergenerational justice and for the Pareto principle.

Since the last ice age, when ice enveloped most of the northern continents, the earth has warmed by about five degrees. Within a century, it is likely to warm by another four or five. This revolution in our climate will have immense and mostly harmful effects on the lives of people not yet born. We are inflicting this harm on our descendants by dumping greenhouse gases into the atmosphere. We can mitigate the harm a little by taking measures to control our emissions of these gases, and to adapt to the changes by, for instance, building sea walls around coastlines threatened by rising sea levels. But these measures will be very expensive, and the costs will be born by us, the present generation, whereas the benefits will come to future generations. How much should we sacrifice for the sake of the future? Economists and philosophers have independently worked on the question of our responsibility to future generations. This book brings their work together and applies it to global warming. It suggests a programme for future research on the economic and ethical issues. The book is intended for economists, and for philosophers and other social scientists who have a little knowledge of economic methods.