Longtermism in an Infinite World

Christian J. Tarsney (Population Wellbeing Initiative, University of Texas at Austin) and Hayden Wilkinson (Global Priorities Institute, University of Oxford)

GPI Working Paper No. 4-2023, forthcoming in Essays on Longtermism

The case for longtermism depends on the vast potential scale of the future. But that same vastness also threatens to undermine the case for longtermism: If the future contains infinite value, then many theories of value that support longtermism (e.g., risk-neutral total utilitarianism) seem to imply that no available action is better than any other. And some strategies for avoiding this conclusion (e.g., exponential time discounting) yield views that are much less supportive of longtermism. This chapter explores how the potential infinitude of the future affects the case for longtermism. We argue that (i) there are reasonable prospects for extending risk- neutral totalism and similar views to infinite contexts and (ii) many such extension strategies still support standard arguments for longtermism, since they imply that when we can only affect (or only predictably affect) a finite part of an infinite universe, we can reason as if only that finite part existed. On the other hand, (iii) there are improbable but not impossible physical scenarios in which our actions can have infinite predictable effects on the far future, and these scenarios create substantial unresolved problems for both infinite ethics and the case for longtermism.

Other working papers

Misjudgment Exacerbates Collective Action Problems – Joshua Lewis (New York University) et al.

In collective action problems, suboptimal collective outcomes arise from each individual optimizing their own wellbeing. Past work assumes individuals do this because they care more about themselves than others. Yet, other factors could also contribute. We examine the role of empirical beliefs. Our results suggest people underestimate individual impact on collective problems. When collective action seems worthwhile, individual action often does not, even if the expected ratio of costs to benefits is the same. …

Tiny probabilities and the value of the far future – Petra Kosonen (Population Wellbeing Initiative, University of Texas at Austin)

Morally speaking, what matters the most is the far future – at least according to Longtermism. The reason why the far future is of utmost importance is that our acts’ expected influence on the value of the world is mainly determined by their consequences in the far future. The case for Longtermism is straightforward: Given the enormous number of people who might exist in the far future, even a tiny probability of affecting how the far future goes outweighs the importance of our acts’ consequences…

‘The only ethical argument for positive 𝛿’? – Andreas Mogensen (Global Priorities Institute, Oxford University)

I consider whether a positive rate of pure intergenerational time preference is justifiable in terms of agent-relative moral reasons relating to partiality between generations, an idea I call ​discounting for kinship​. I respond to Parfit’s objections to discounting for kinship, but then highlight a number of apparent limitations of this…