EA - Paper summary: The Epistemic Challenge to Longtermism (Christian Tarsney) by Global Priorities Institute

Link to original articleWelcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Paper summary: The Epistemic Challenge to Longtermism (Christian Tarsney), published by Global Priorities Institute on October 11, 2022 on The Effective Altruism Forum. Note: The Global Priorities Institute (GPI) has started to create summaries of some working papers by GPI researchers with the aim to make our research more accessible to people outside of academic philosophy (e.g. interested people in the effective altruism community). We welcome any feedback on the usefulness of these summaries. Summary: The Epistemic Challenge to Longtermism This is a summary of the GPI Working Paper "The epistemic challenge to longtermism" by Christian Tarsney. The summary was written by Elliott Thornley. According to longtermism, what we should do mainly depends on how our actions might affect the long-term future. This claim faces a challenge: the course of the long-term future is difficult to predict, and the effects of our actions on the long-term future might be so unpredictable as to make longtermism false. In “The epistemic challenge to longtermism”, Christian Tarsney evaluates one version of this epistemic challenge and comes to a mixed conclusion. On some plausible worldviews, longtermism stands up to the epistemic challenge. On others, longtermism’s status depends on whether we should take certain high-stakes, long-shot gambles. Tarsney begins by assuming expectational utilitarianism: roughly, the view that we should assign precise probabilities to all decision-relevant possibilities, value possible futures in line with their total welfare, and maximise expected value. This assumption sets aside ethical challenges to longtermism and focuses the discussion on the epistemic challenge. Persistent-difference strategies Tarsney outlines one broad class of strategies for improving the long-term future: persistent-difference strategies. These strategies aim to put the world into some valuable state S when it would otherwise have been in some less valuable state ¬S, in the hope that this difference will persist for a long time. Epistemic persistence skepticism is the view that identifying interventions likely to make a persistent difference is prohibitively difficult — so difficult that the actions with the greatest expected value do most of their good in the near-term. It is this version of the epistemic challenge that Tarsney focuses on in this paper. To assess the truth of epistemic persistence skepticism, Tarsney compares the expected value of a neartermist benchmark intervention N to the expected value of a longtermist intervention L. In his example, N is spending $1 million on public health programmes in the developing world, leading to 10,000 extra quality-adjusted life years in expectation. L is spending $1 million on pandemic-prevention research, with the aim of preventing an existential catastrophe and thereby making a persistent difference. Exogenous nullifying events Persistent-difference strategies are threatened by what Tarsney calls exogenous nullifying events (ENEs), which come in two types. Negative ENEs are far-future events that put the world into the less valuable state ¬S. In the context of the longtermist intervention L, in which the valuable target state S is the existence of an intelligent civilization in the accessible universe, negative ENEs are existential catastrophes that might befall such a civilization. Examples include self-destructive wars, lethal pathogens, and vacuum decay. Positive ENEs, on the other hand, are far-future events that put the world into the more valuable state S. In the context of L, these are events that give rise to an intelligent civilization in the accessible universe where none existed previously. This might happen via evolution, or via the arrival of a civilization from outside the accessible universe. What unites negative...