Abstract

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.