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

Moral uncertainty and public justification – Jacob Barrett (Global Priorities Institute, University of Oxford) and Andreas T Schmidt (University of Groningen)

Moral uncertainty and disagreement pervade our lives. Yet we still need to make decisions and act, both in individual and political contexts. So, what should we do? The moral uncertainty approach provides a theory of what individuals morally ought to do when they are uncertain about morality…

The Conservation Multiplier – Bård Harstad (University of Oslo)

Every government that controls an exhaustible resource must decide whether to exploit it or to conserve and thereby let the subsequent government decide whether to exploit or conserve. This paper develops a positive theory of this situation and shows when a small change in parameter values has a multiplier effect on exploitation. The multiplier strengthens the influence of a lobby paying for exploitation, and of a donor compensating for conservation. …

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Effective altruism is the use of evidence and careful reasoning to work out how to maximize positive impact on others with a given unit of resources, and the taking of action on that basis. It’s a philosophy and a social movement that is gaining considerable steam in the philanthropic world. For example,…