John Broome

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 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.

In 2002, Bernard Williams delivered a lecture that revisited the arguments of his article 'Ought and moral obligation', published in his Moral Luck. The lecture attributed to the earlier article the thesis that there are no ‘personal’ or (as I put it) ‘owned’ oughts. It also rejected this thesis. This paper explains the idea of an owned ought, and supports Williams’s lecture in asserting that there are owned oughts. It also examines the question of how accurately Williams’s later lecture interprets his earlier article.

Most properties have comparatives, which are relations. For instance, the property of width has the comparative relation denoted by `_ is wider than _'. Let us say a property is reducible to its comparative if any statement that refers to the property has the same meaning as another statement that refers to the comparative instead. Width is not reducible to its comparative. To be sure, many statements that refer to width are reducible: for instance, `The Mississippi is wide' means the same as `The Mississippi is wider than most rivers'. But some statements that refer to width are not reducible: for instance, `Electrons have zero width' is not. A property is not reducible to its comparative if it has absolute degrees, and specifically an absolute zero. A property's comparative relation places things in an order from those that have the property least to those that have it most. If there is an absolute zero point somewhere in this ordering, the property is not reducible to its comparative. For width, there is an absolute zero at one end of the ordering, so width is not reducible. The property of goodness is reducible to its comparative, betterness. In particular, there is no absolute zero of goodness. Things are ordered by betterness – some things are better than others – but nothing is absolutely good or absolutely bad. This is an exaggeration. In certain applications, goodness does have absolute degrees of a sort, and an absolute zero. For instance, it makes sense to say an event is good, and another event bad. These are absolute degrees of a sort, but they are themselves reducible to betterness. To say an event is good simply means the event is better than what would otherwise have happened. The goodness of lives has a different sort of absolute zero. Lives are ordered by betterness; some lives are better than others. We can make sense of the question `Where in this ordering is the division between lives that are good and those that are bad?' The division between good and bad lives is again reducible to betterness. To say a person's life is good means it is better that the person should continue living, rather than that she should die. Or it may mean it is better that her life should be lived rather than that it should never have been lived at all. As it is often put: a good life is a life worth living. Derek Parfit appears to attach a different sense to the idea of a good life. He appears to mean a life that contains a preponderance of good things (such as pleasure) over bad things (such as pain). If a life contains no good things and no bad things, it has zero goodness in this sense. In this sense, absolute goodness and the absolute zero of goodness are not reducible to betterness. However, this is a naturalistic sense of goodness, and it is subject to the open-question objection. If a life contains no good things and no bad things, it is an open question whether it has zero goodness. It might, for instance, be a bad thing that this life should be lived. In discussing the evil of death, some philosophers seem to have been searching for an absolute goodness that is not reducible to betterness. Thomas Nagel speaks of an asymmetry between what is good about life and what is bad about death. But if a person's life is good, that only means it would be better that she should continue living than that she should die. And if a person's death would be bad, that only means it would be worse that she should die than that she should continue living. So there can be no asymmetry.

Two options are incommensurate in value if neither is better than the other, and if a small improvement or worsening of one does not necessarily make it determinately better or worse than the other. If a person faces a sequence of choices between incommensurate options, she may end up with a worse options than she could have had, even though none of her choices are irrational. Yet it seems that rationality should save her from this bad outcome. This is the practical problem posed by incommensurability of values, and it may be solved by a new account of practical reasoning.

Intuition suggests there is no value in adding people to the population if it brings no benefits to people already living: creating people is morally neutral in itself. This paper examines the difficulties of incorporating this intuition into a coherent theory of the value of population. It takes three existing theories within welfare economics - average utilitarianism, relativist utilitarianism, and critical-level utilitarianism - and considers whether they can satisfactorily accommodate the intuition that creating people is neutral.