The case for strong longtermism

Hilary Greaves and William MacAskill (Global Priorities Institute, University of Oxford)

GPI Working Paper No. 5-2021

A striking fact about the history of civilisation is just how early we are in it. There are 5000 years of recorded history behind us, but how many years are still to come? If we merely last as long as the typical mammalian species, we still have over 200,000 years to go (Barnosky et al. 2011); there could be a further one billion years until the Earth is no longer habitable for humans (Wolf and Toon 2015); and trillions of years until the last conventional star formations (Adams and Laughlin 1999:34). Even on the most conservative of these timelines, we have progressed through a tiny fraction of history. If humanity’s saga were a novel, we would be on the very first page.

Other working papers

High risk, low reward: A challenge to the astronomical value of existential risk mitigation – David Thorstad (Global Priorities Institute, University of Oxford)

Many philosophers defend two claims: the astronomical value thesis that it is astronomically important to mitigate existential risks to humanity, and existential risk pessimism, the claim that humanity faces high levels of existential risk. It is natural to think that existential risk pessimism supports the astronomical value thesis. In this paper, I argue that precisely the opposite is true. Across a range of assumptions, existential risk pessimism significantly reduces the value of existential risk mitigation…

The epistemic challenge to longtermism – Christian Tarsney (Global Priorities Institute, Oxford University)

Longtermists claim that what we ought to do is mainly determined by how our actions might affect the very long-run future. A natural objection to longtermism is that these effects may be nearly impossible to predict— perhaps so close to impossible that, despite the astronomical importance of the far future, the expected value of our present actions is mainly determined by near-term considerations. This paper aims to precisify and evaluate one version of this epistemic objection to longtermism…

Cassandra’s Curse: A second tragedy of the commons – Philippe Colo (ETH Zurich)

This paper studies why scientific forecasts regarding exceptional or rare events generally fail to trigger adequate public response. I consider a game of contribution to a public bad. Prior to the game, I assume contributors receive non-verifiable expert advice regarding uncertain damages. In addition, I assume that the expert cares only about social welfare. Under mild assumptions, I show that no information transmission can happen at equilibrium when the number of contributors…