Strong longtermism and the challenge from anti-aggregative moral views

Karri Heikkinen (University College London)

GPI Working Paper No. 5 - 2022

Greaves and MacAskill (2019) argue for strong longtermism, according to which, in a wide class of decision situations, the option that is ex ante best, and the one we ex ante ought to choose, is the option that makes the very long-run future go best. One important aspect of their argument is the claim that strong longtermism is compatible with a wide range of ethical assumptions, including plausible non-consequentialist views. In this essay, I challenge this claim. I argue that strong longtermism is incompatible with a range of non-aggregative and partially aggregative moral views. Furthermore, I argue that the conflict between these views and strong longtermism is so deep that those in favour of strong longtermism are better off arguing against them, rather than trying to modify their own view. The upshot of this discussion is that strong longtermism is not as robust to plausible variations in underlying ethical assumptions as Greaves and MacAskill claim. In particular, the stand we take on interpersonal aggregation has important implications on whether making the future go as well as possible should be a global priority.

Other working papers

Should longtermists recommend hastening extinction rather than delaying it? – Richard Pettigrew (University of Bristol)

Longtermism is the view that the most urgent global priorities, and those to which we should devote the largest portion of our current resources, are those that focus on ensuring a long future for humanity, and perhaps sentient or intelligent life more generally, and improving the quality of those lives in that long future. The central argument for this conclusion is that, given a fixed amount of are source that we are able to devote to global priorities, the longtermist’s favoured interventions have…

Doomsday rings twice – Andreas Mogensen (Global Priorities Institute, Oxford University)

This paper considers the argument according to which, because we should regard it as a priori very unlikely that we are among the most important people who will ever exist, we should increase our confidence that the human species will not persist beyond the current historical era, which seems to represent…

Are we living at the hinge of history? – William MacAskill (Global Priorities Institute, Oxford University)

In the final pages of On What Matters, Volume II, Derek Parfit comments: ‘We live during the hinge of history… If we act wisely in the next few centuries, humanity will survive its most dangerous and decisive period… What now matters most is that we avoid ending human history.’ This passage echoes Parfit’s comment, in Reasons and Persons, that ‘the next few centuries will be the most important in human history’. …