2025

The Case for Strong Longtermism

August 2025

Let strong longtermism be the thesis that in a wide class of decision situations, the option that is ex ante best is contained in a fairly small subset of options whose ex ante effects on the very long-run future are best. If this thesis is correct, it suggests that for decision purposes, we can often simply ignore shorter-run effects: the primary determinant of how good an option is (ex ante) is how good its effects on the very long run are. This paper sets out an argument for strong longtermism. We argue that the case for this thesis is quite robust to plausible variations in various normative assumptions, including relating to population ethics, interpersonal aggregation, and decision theory. We also suggest that while strong longtermism as defined above is a purely axiological thesis, a corresponding deontic thesis plausibly follows, even by non-consequentialist lights.

Introducing Better Futures

August 2025

Suppose we want the future to go better. What should we do?

One approach is to avoid near-term catastrophes, like human extinction. This essay series explores a different, complementary, approach: improving on futures where we survive, to achieve a truly great future.

No Easy Eutopia

August 2025

How big is the target we need to hit to reach a mostly great future? Fin Moorehouse and I argue that, on most plausible views, only a narrow range of futures meet this bar, and even common-sense utopias miss out on almost all their potential.

Convergence and Compromise

August 2025

Even if the target is narrow, will there be forces which nonetheless hone in on near-best futures? Fin Moorehouse and I argue society is unlikely to converge on them by default. Trade and compromise make eutopias seem more achievable, but still we should expect ‘default’ outcomes to fall far short.

Persistent Path-Dependence

August 2025

Over sufficiently long time horizons, will the effects of actions to improve the quality of the future just ‘wash out’? Against this view, I argue a number of plausible near-term events will have persistent and predictable path-dependent effects on the value of the future.

How to Make the Future Better

August 2025

I suggest a number of concrete actions we can take now to make the future go better.

Supplement: The Basic Case for Better Futures

August 2025

How do we compare working on reducing catastrophe with improving the quality of the future? We introduce a simple model (EV ≈ S*F) and use the 'scale, neglectedness, tractability' framework to argue that improving Flourishing is of comparable priority to increasing the chance of Surviving.

Preparing for the Intelligence Explosion

arXiv preprint arXiv:2506.14863 (June 17, 2025)

AI that can accelerate research could drive a century of technological progress over just a few years. During such a period, new technological or political developments will raise consequential and hard-to-reverse decisions, in rapid succession. We call these developments grand challenges. These challenges include new weapons of mass destruction, AI-enabled autocracies, races to grab offworld resources, and digital beings worthy of moral consideration, as well as opportunities to dramatically improve the quality of life and collective decision-making. We argue that these challenges cannot always be delegated to future AI systems, and suggest things we can do today to meaningfully improve our prospects. AGI preparedness is therefore not just about ensuring that advanced AI systems are aligned: we should be preparing, now, for the disorienting range of developments an intelligence explosion would bring.

Intelsat as a Model for International AGI Governance

March 2025

If there is an international project to build artificial general intelligence (“AGI”), how should it be designed? Existing scholarship has looked to historical models for inspiration, often suggesting the Manhattan Project or CERN as the closest analogues. But AGI is a fundamentally general-purpose technology, and is likely to be used primarily for commercial purposes rather than military or scientific ones.

This report presents an under-discussed alternative: Intelsat, an international organization founded to establish and own the global satellite communications system. We show that Intelsat is proof of concept that a multilateral project to build a commercially and strategically important technology is possible and can achieve intended objectives—providing major benefits to both the US and its allies compared to the US acting alone. We conclude that ‘Intelsat for AGI’ is a valuable complement to existing models of AGI governance.

How Suddenly will AI Accelerate the Pace of AI progress?

March 2025

Today, human efforts drive AI progress. But at some point, all AI progress will be driven by AI. This piece analyzes the transition from human-driven to AI-driven progress.

How Far Can AI Progress Before Hitting Effective Physical Limits?

March 2025

In simplified models of intelligence explosions, accelerating AI progress goes to infinity. But in reality, we will hit effective limits on AI intelligence. In this piece, we analyze the room for improvement in three inputs to AI development: software, chip technology and chip production.

Three Types of Intelligence Explosion

March 2025

Once AI systems can design and build even more capable AI systems, we could see an intelligence explosion, where AI capabilities rapidly increase to well past human performance.

The classic intelligence explosion scenario involves a feedback loop where AI improves AI software. But AI could also improve other inputs to AI development. This paper analyses three feedback loops in AI development

2024

On the Desire to Make a Difference

Philosophical Studies, vol. 181, no. 6 (July 2024), pp. 1599–1626

True benevolence is, most fundamentally, a desire that the world be better. It is natural and common, however, to frame thinking about benevolence indirectly, in terms of a desire to make a difference to how good the world is. This would be an innocuous shift if desires to make a difference were extensionally equivalent to desires that the world be better. This paper shows that at least on some common ways of making a “desire to make a difference” precise, this extensional equivalence fails. Where it fails, “difference-making preferences” run counter to the ideals of benevolence. In particular, in the context of decision making under uncertainty, coupling a “difference-making” framing in a natural way with risk aversion leads to preferences that violate stochastic dominance, and that lead to a strong form of collective defeat, from the point of view of betterness. Difference-making framings and true benevolence are not strictly mutually inconsistent, but agents seeking to implement true benevolence must take care to avoid the various pitfalls that we outline.

2022

Are We Living at the Hinge of History?

Ethics and Existence: The Legacy of Derek Parfit, Jeff McMahan, Tim Campbell, James Goodrich, and Ketan Ramakrishnan (eds), 2022, pp. 331–357

I give an “outside view” argument against Parfit’s claim that humanity sits at a “hinge of history”.

Evolution, Utilitarianism, and Normative Uncertainty: The Practical Significance of Debunking Arguments

J. Ethics & Soc. Phil., vol. 22 (2022), p. 338

It has been argued that evolutionary considerations favour utilitarianism by selectively debunking its competitors. However, evolutionary considerations also seem to undermine the practical significance of utilitarianism, since common-sense beliefs about well-being seem like prime candidates for evolutionary debunking. We argue that the practical significance of utilitarianism is not undermined in this way if we understand the requirements of practical rationality as sensitive to normative uncertainty. We consider the view that rational decision-making under normative uncertainty requires maximizing expected choice-worthiness, as well as the possibility that different theories’ choice-worthiness rankings are not all interval-scale measurable nor intertheoretically comparable.

2021

The Paralysis Argument

2019

Many everyday actions have major but unforeseeable long-term consequences. Some argue that this fact poses a serious problem for consequentialist moral theories. We argue that the problem for non-consequentialists is greater still. Standard non-consequentialist constraints on doing harm combined with the long-run impacts of everyday actions entail, absurdly, that we should try to do as little as possible. We call this the Paralysis Argument. After laying out the argument, we consider and respond to a number of objections. We then suggest what we believe is the most promising response: to accept, in practice, a highly demanding morality of beneficence with a long-term focus.

The Evidentialist's Wager

The Journal of Philosophy, 2021

Suppose that an altruistic and morally motivated agent who is uncertain between evidential decision theory (EDT) and causal decision theory (CDT) finds herself in a situation in which the two theories give conflicting verdicts. We argue that even if she has significantly higher credence in CDT, she should nevertheless act in accordance with EDT. First, we claim that the appropriate response to normative uncertainty is to hedge one’s bets. That is, if the stakes are much higher on one theory than another, and the credences you assign to each of these theories aren’t very different, then it’s appropriate to choose the option which performs best on the high-stakes theory. Second, we show that, given the assumption of altruism, the existence of correlated decision-makers will increase the stakes for EDT but leave the stakes for CDT unaffected. Together, these two claims imply that whenever there are sufficiently many correlated agents, the appropriate response is to act in accordance with EDT.

Longtermist Institutional Reform

The Long View, Natalie Cargill (ed)., 2021

In all probability, future generations will outnumber us by thousands or millions to one. In the aggregate, their interests therefore matter enormously, and anything we can do to steer the future of civilization onto a better trajectory is of tremendous moral importance. This is the guiding thought that defines the philosophy of longtermism. Political science tells us that the practices of most governments are at stark odds with longtermism. But the problems of political short-termism are neither necessary nor inevitable. In principle, the state could serve as a powerful tool for positively shaping the long-term future. In this chapter, we make some suggestions about how to align government incentives with the interests of future generations. First, in Section II, we explain the root causes of political short-termism. Then, in Section III, we propose and defend four institutional reforms that we think would be promising ways to increase the time horizons of governments: 1) government research institutions and archivists; 2) posterity impact assessments; 3) futures assemblies; and 4) legislative houses for future generations. Section IV concludes with five additional reforms that are promising but require further research: to fully resolve the problem of political short-termism, we must develop a comprehensive research program on effective longtermist political institutions.

The Moral Case for Long-Term Thinking

2021

This chapter makes the case for strong longtermism: the claim that, in many situations, impact on the long-run future is the most important feature of our actions. Our case begins with the observation that an astronomical number of people could exist in the aeons to come. Even on conservative estimates, the expected future population is enormous. We then add a moral claim: all the consequences of our actions matter. In particular, the moral importance of what happens does not depend on when it happens. That pushes us toward strong longtermism. We then address a few potential concerns, the first of which is that it is impossible to have any sufficiently predictable influence on the course of the long-run future. We argue that this is not true. Some actions can reasonably be expected to improve humanity’s long-term prospects. These include reducing the risk of human extinction, preventing climate change, guiding the development of artificial intelligence, and investing funds for later use. We end by arguing that these actions are more than just extremely effective ways to do good. Since the benefits of longtermist efforts are large and the personal costs are comparatively small, we are morally required to take up these efforts.

What Should We Agree On About the Repugnant Conclusion?

Utilitas, vol. 33, no. 4 (December 2021), pp. 379–383

A statement that entailing the Repugnant Conclusion is not decisive reason to reject a theory of population ethics.

2020

What Is Effective Altruism?

International Encyclopedia of Ethics (June 15, 2020), pp. 1–9

Climate change is on course to cause millions of deaths and cost the world economy trillions of dollars. Nearly a billion people live in extreme poverty, millions of them dying each year of easily preventable diseases. Just a small fraction of the thousands of nuclear weapons on hair‐trigger alert could easily bring about a global catastrophe. New technologies like synthetic biology and artificial intelligence bring unprecedented risks. Meanwhile, year after year, billions and billions of factory‐farmed animals live and die in misery. Given the number of severe problems facing the world today, and the resources required to solve them, we may feel at a loss as to where to even begin. The good news is that we can improve things with the right use of money, time, talent, and effort. These resources can bring about a great deal of improvement, or very little, depending on how they are allocated. The effective altruism movement consists of a growing global community of people who use reason and evidence to assess how to do as much good as possible, and who take action on this basis.

Statistical normalization methods in interpersonal and intertheoretic comparisons

The Journal of Philosophy, 2020

A major problem for interpersonal aggregation is how to compare utility across individuals; a major problem for decision-making under normative uncertainty is the formally analogous problem of how to compare choice-worthiness across theories. We introduce and study a class of methods, which we call statistical normalization methods, for making interpersonal comparisons of utility and intertheoretic comparisons of choice-worthiness. We argue against the statistical normalization methods that have been proposed in the literature. We argue, instead, in favor of normalization of variance: we claim that this is the account that most plausibly gives all individuals or theories ‘equal say’. To this end, we provide two proofs that variance normalization has desirable properties that all other normalization methods lack, though we also show how different assumptions could lead one to axiomatize alternative statistical normalization methods.

2019

The Definition of Effective Altruism

Effective Altruism: Philosophical Issues, 2019

The term “effective altruism” has no official definition, meaning that different authors will inevitably understand the term in different ways. Since this harbours the potential for considerable confusion, William MacAskill, one of the leaders of the effective altruism movement, has contributed a chapter aimed at forestalling some of these potential confusions. In this chapter, MacAskill first outlines a brief history of the effective altruism movement. He then proposes his preferred definition of “effective altruism”, aiming to capture the central activities and concerns of those most deeply involved in the movement. Finally, he replies to various common misconceptions about the movement. These include the views that effective altruism is just utilitarianism, that it is purely about poverty alleviation, that it is purely about donations, and that it in principle ignores possibilities for systemic change.

Aid scepticism and Effective Altruism

Journal of Practical Ethics, 2019

In the article, ‘Being Good in a World of Need: Some Empirical Worries and an Uncomfortable Philosophical Possibility,’ Larry Temkin presents some concerns about the possible impact of international aid on the poorest people in the world, suggesting that the nature of the duties of beneficence of the global rich to the global poor are much more murky than some people have made out.

In this article, I’ll respond to Temkin from the perspective of effective altruism—one of the targets he attacks. I’ll argue that Temkin’s critique has little empirical justification, given the conclusions he wants to reach, and is therefore impotent.

Practical Ethics given Moral Uncertainty

Utilitas, 2019

A number of philosophers have claimed that we should take not just empirical uncertainty but also fundamental moral uncertainty into account in our decision-making, and that, despite widespread moral disagreement, doing so would allow us to draw robust lessons for some issues in practical ethics. In this article, I argue that, so far, the implications for practical ethics have been drawn too simplistically. First, the implications of moral uncertainty for normative ethics are far more wide-ranging than has been noted so far. Second, one can't straightforwardly argue from moral uncertainty to particular conclusions in practical ethics, both because of ‘interaction’ effects between moral issues, and because of the variety of different possible intertheoretic comparisons that one can reasonably endorse.

A Research Agenda for the Global Priorities Institute

Global Priorities Institute, 2019, co-authored with Hilary Greaves, Rossa O’Keefe-O’Donovan & Philip Trammell

In this research agenda, we outline the landscape for global priorities research.

2018

Understanding Effective Altruism and its Challenges

David Boonin (ed.), Palgrave Handbook of Philosophy and Public Policy, 2018

Effective altruism is the use of evidence and reason to figure out how to benefit others as much as possible and the taking of action on that basis. This chapter discusses the moral framework and methodological approach that effective altruism uses to prioritize causes, charities, and careers, and examines some of the world problems that, on this perspective, appear to be most urgent and important: global health and development, non-human animal suffering, and risks to long-term human survival. It then lays out some of the most important unsolved problems facing the effective altruist project.

Why Maximize Expected Choice-Worthiness?

Noûs, 2018

This paper argues in favor of a particular account of decision‐making under normative uncertainty: that, when it is possible to do so, one should maximize expected choice‐worthiness . Though this position has been often suggested in the literature and is often taken to be the ‘default’ view, it has so far received little in the way of positive argument in its favor. After dealing with some preliminaries and giving the basic motivation for taking normative uncertainty into account in our decision‐making, we consider and provide new arguments against two rival accounts that have been offered—the accounts that we call ‘My Favorite Theory’ and ‘My Favorite Option’. We then give a novel argument for comparativism —the view that, under normative uncertainty, one should take into account both probabilities of different theories and magnitudes of choice‐worthiness. Finally, we further argue in favor of maximizing expected choice‐worthiness and consider and respond to five objections.

Giving isn’t demanding

Paul Woodruff (ed.), The Ethics of Giving: Philosophers' Perspectives on Philanthropy, Oxford: Oxford University Press, 2018, pp. 178-203 (co-written with Andreas Mogensen and Toby Ord)

In this chapter, we argue that a Very Weak Principle of Sacrifice, requiring us to give 10% of our income to cost-effective charities, is not very demanding at all, and therefore that the “demandingness” objection has not even pro tanto force against it. Whatever one thinks about the demandingness of Singer’s two proposed principles, one should therefore endorse the Very Weak Principle of Sacrifice and agree that we still have significant obligations to use our income to effectively improve the lives of others.

2017

Effective Altruism - Introduction

Essays in Philosophy, vol. 18, Issue 1 (2017)

I define effective altruism, and introduce essays related to the concepts in the journal.

Effective Reducetarianism

The Reducetarian Solution, Brian Kateman (ed.), 2017.

2014

Replaceability, Career Choice, and Making a Difference

Ethical Theory and Moral Practice, vol. 17, no. 2 (April, 2014), pp. 269-283

I defend the idea that deliberately pursuing a lucrative career in order to donate a large proportion of one's earnings is typically ethically preferable to a career within the charity sector.

Normative Uncertainty

PhD dissertation, March 2014

What ought you to do when you don't know what you ought to do? I argue broadly in favour of the idea that we should treat moral uncertainty and empirical uncertainty analogously, with expected utility theory providing the correct formal framework. I provide some modifications to this idea in order to overcome some problems, and then chart its implications for practical ethics and decision theory.

2013

The Infectiousness of Nihilism

Ethics, vol. 123, no. 3 (April, 2013), pp. 508-520

In “Rejecting Ethical Deflationism,” Jacob Ross argues that a rational decision maker is permitted, for the purposes of practical reasoning, to assume that nihilism is false. I argue that Ross’s argument fails because the principle he relies on conflicts with more plausible principles of rationality and leads to preference cycles. I then show how the infectiousness of nihilism, and of incomparability more generally, poses a serious problem for the larger project of attempting to incorporate moral uncertainty into expected value maximization style reasoning.