Michael Plant

I review MacAskill's book What We Owe The Future, which makes the case for longtermism, the idea that positively influencing the longterm future is a key moral priority of our time. After summarising it, I raise four challenges to the nature or presentation of his case. First, I point out MacAskill's stated three-premise 'case' for longtermism is not a valid argument. Second, I argue his case is not, as he describes it, 'simple' and 'uncontroversial'; MacAskill brushes over crucial subtleties and mauls a strawman. Third, I am unpersuaded by the argument that we can influence the longterm future; the book does not contain a single example that shows this has happened before, so we should be sceptical we can do so. Fourth, I question the practical importance of longtermism. MacAskill argues we should do more to prevent global catastrophic risks from e.g. AI and nuclear war. Longtermism may give us more reason to care about them but it is neither necessary nor sufficient to make those the priorities.

Suppose you want to do as much good as possible. What should you do? According to members of the effective altruism movement—which has produced much of the thinking on this issue and counts several moral philosophers as its key protagonists—we should prioritise among the world’s problems by assessing their scale, solvability, and neglectedness. Once we’ve done this, the three top priorities, not necessarily in this order, are (1) aiding the world’s poorest people by providing life-saving medical treatments or alleviating poverty itself, (2) preventing global catastrophic risks, such as those posed by nuclear war or rogue artificial intelligence, and (3) ending factory farming. These claims are both plausible and striking. If correct, they should prompt a stark revision of how we approach our altruistic activities. However, the project of determining how to do the most good—as opposed to say, whether we should do the most good—has only recently, within the last ten years, become the subject of serious academic attention. Many key claims have not yet been carefully scrutinised. This is a cause for concern: are effective altruists doing good badly? In this thesis, I critique and develop some of the latest claims about how individuals can do the most good. I do this in three areas: the value of saving lives (preventing premature deaths), how best to improve lives (making people happier during their lives), and cause prioritisation methodology (frameworks for determining which problems are the highest priorities). In each case, I raise novel theoretical considerations that, when incorporated, change the analysis. Roughly speaking, my main conclusions are (1) saving lives is not as straightforwardly good we tend to suppose, may not be good at all, and is not clearly a priority; (2) happiness can be measured through self-reports and, based on the self-reported evidence, treating mental health stands out as an overlooked problem that may be an even more cost-effective way to improve lives than alleviating poverty; (3) the cause prioritisation methodology proposed by effective altruists needs to be moderately reconceptualised and, when it is, it turns out it is not as illuminating a tool as we might have thought and hoped.

While life satisfaction theories (LSTs) of well-being are barely discussed in philosophy, they are popular among social scientists and wider society. When philosophers have discussed LSTs, they are taken to be a distinct alternative to the three canonical accounts of well-being—hedonism, desire theories, the objective list. This essay makes three main claims. First, on closer inspection, LSTs are indistinguishable from a type of desire theory—the global desire theory. Second, the life satisfaction/global desire theories are the only subjectivist accounts of well-being in the sense that they maintain individuals decide what makes their lives go well for them; hedonism and other desire theories are subjectivist only in some alternative senses. Third, subjectivism is implausible, although for different reasons from those that are usually given. I examine what I take to be the two main current objections to LSTs and argue that they are unproblematic. I then raise two different, challenging objections. The first is novel. The second has been noted in passing, but its seriousness underestimated. I close by sketching some non-obvious difficulties that subjectivists will face if they attempt to show rival objectivist theories suffer even more counterintuitive implications. Although subjectivism has a strong intuitive pull, we should be ready to abandon it in favour of an objectivist theory—although it is not my purpose here to say which one.

There are long-standing doubts about whether data from subjective scales—for instance, self-reports of happiness—are cardinally comparable. It is unclear how to assess whether these doubts are justified without first addressing two unresolved theoretical questions: how do people interpret subjective scales? Which assumptions are required for cardinal comparability? This paper offers answers to both. It proposes an explanation for scale interpretation derived from philosophy of language and game theory. In short: conversation is a cooperative endeavour governed by various maxims (Grice 1989); because subjective scales are vague and individuals want to make themselves understood, scale interpretation is a search for a focal point (Schelling 1960). A specific focal point it hypothesised; if this hypothesis is correct, subjective data will be cardinally comparable. Four individually necessary and jointly sufficient conditions for cardinal comparability are specified. The paper then argues this hypothesis can be empirically be tested, makes an initial attempt to do so using subjective well-being data, and concludes it is supported. Numerous areas for further research are identified including, at the end of the paper, how certain tests could be used to ‘correct’ subjective data if they are not cardinal.