Derek Parfit

(1942 - 2017)

Explains why C cannot be directly self‐defeating. Theories are agent‐relative if they give different agents different aims. Two such theories are S and Common Sense Morality, or M. It is often true that, if each of several people does what would be best for themselves, that would be worse for all these people. In such cases, S is directly collectively self‐defeating. In moral analogues of such cases, M is similarly self‐defeating. The chapter describes how these problems can have political, psychological, or moral solutions.

This chapter discusses problems for informational patternism and the popular soul theory of personal identity, suggests that they are incoherent, and urges that the self does not really exist. It employs the science fiction pseudotechnology of a teleporter and presents the example of split brains from actual neuroscience cases. There are two theories about what persons are, and what is involved in a person's continued existence over time. On the Ego Theory, a person's continued existence cannot be explained except as the continued existence of a particular Ego, or subject of experiences. According to the Bundle Theory we must claim that there are long series of different mental states and events, each series being what we call one life. The split‐brain cases provide one argument for one view about the nature of persons. In the other, a person's brain is divided, and the halves are transplanted in two different bodies.

Suppose we discover how we could live for a thousand years, but in a way that made us unable to have children. Everyone chooses to live these long lives. After we all die, human history ends, since there would be no future people. Would that be bad? Would we have acted wrongly? Some pessimists would answer No. These people are saddened by the suffering in most people’s lives, and they believe it would be wrong to inflict such suffering on others by having children. In earlier centuries, this bleak view was fairly plausible. But our successors would be able to prevent most human suffering. Some optimists would also answer No . . . These [views] are, I believe, deeply mistaken. Given what our successors could achieve in the next million or billion years, here and elsewhere in our galaxy, it would be likely to be very much worse if there were no future people.

This article discusses the relation between prioritarian and egalitarian principles, whether and why we need to appeal to both kinds of principle, how prioritarians can answer various objections, especially those put forward by Michael Otsuka and Alex Voorhoeve, the moral difference between cases in which our acts could affect only one person or two or more people, veil of ignorance contractualism and utilitarianism, what prioritarians should claim about cases in which the effects of our acts are uncertain, the relative moral importance of actual and expectable benefits, whether people should sometimes be given various chances of receiving benefits, and principles that appeal to competing claims

When we have a normative reason, and we act for that reason, it becomes our motivating reason. But we can have either kind of reason without having the other. Thus, if I jump into the canal, my motivating reason was provided by my belief; but I had no normative reason to jump. I merely thought I did. And, if I failed to notice that the canal was frozen, I had a reason not to jump that, because it was unknown to me, did not motivate me. Though we can have normative reasons without being motivated, and vice versa, such reasons are closely related to our motivation. There are, however, very different views about what this relation is. This disagreement raises wider questions about what normative reasons are, and about which reasons there are. After sketching some of these views, I shall discuss some arguments by Williams, and then say where, in my opinion, the truth lies. [...] I [will] suggest why, as I believe, we should be non-reductive normative realists, and should regard all reasons as external.