High risk, low reward: A challenge to the astronomical value of existential risk mitigation

David Thorstad (Global Priorities Institute, University of Oxford)

GPI Working Paper No. 6-2023, published in Philosophy and Public Affairs

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, so much so that pessimism threatens to falsify the astronomical value thesis. I argue that the best way to reconcile existential risk pessimism with the astronomical value thesis relies on a questionable empirical assumption. I conclude by drawing out philosophical implications of this discussion, including a transformed understanding of the demandingness objection to consequentialism, reduced prospects for ethical longtermism, and a diminished moral importance of existential risk mitigation.

Other working papers

Longtermist institutional reform – Tyler M. John (Rutgers University) and William MacAskill (Global Priorities Institute, Oxford University)

There is a vast number of people who will live in the centuries and millennia to come. Even if homo sapiens survives merely as long as a typical species, we have hundreds of thousands of years ahead of us. And our future potential could be much greater than that again: it will be hundreds of millions of years until the Earth is sterilized by the expansion of the Sun, and many trillions of years before the last stars die out. …

Moral demands and the far future – Andreas Mogensen (Global Priorities Institute, Oxford University)

I argue that moral philosophers have either misunderstood the problem of moral demandingness or at least failed to recognize important dimensions of the problem that undermine many standard assumptions. It has been assumed that utilitarianism concretely directs us to maximize welfare within a generation by transferring resources to people currently living in extreme poverty. In fact, utilitarianism seems to imply that any obligation to help people who are currently badly off is trumped by obligations to undertake actions targeted at improving the value…

Non-additive axiologies in large worlds – Christian Tarsney and Teruji Thomas (Global Priorities Institute, Oxford University)

Is the overall value of a world just the sum of values contributed by each value-bearing entity in that world? Additively separable axiologies (like total utilitarianism, prioritarianism, and critical level views) say ‘yes’, but non-additive axiologies (like average utilitarianism, rank-discounted utilitarianism, and variable value views) say ‘no’…