Theron Pummer

I am a Professor of Philosophy at the University of St Andrews. I focus mainly on problems in ethics. Prior to joining St Andrews, I was a Junior Research Fellow at the University of Oxford. I received my PhD from the University of California San Diego. I have also held visiting positions at the Australian National University and the University of Oxford. I am an associate editor of Journal of Moral Philosophy and a section editor of Philosophy Compass. My publications can be found below.
Curriculum Vitae


Hypersensitive Ethics: Much Ado about Nearly Nothing (under contract) Oxford University Press

This book provides the first systematic exploration of evaluative hypersensitivity, its varieties, tenability, and importance. Such hypersensitivity occurs when an extreme evaluative difference depends wholly on a slight non-evaluative difference. I argue hypersensitivity does not exist. For example, if two long pains are exactly similar but for the fact that one is slightly more intense for just a second, neither is vastly worse than the other. I argue that the rejection of hypersensitivity often supports aggregation between things that are separated by a series of slight non-evaluative differences. For example, it supports aggregation between intense pain and mild pain in the sense that for any amount of intense pain, there is some amount of mild pain that is worse. The scope of such aggregation interacts with the metaphysical question of which non-evaluative differences are matters of slight degrees. Is being a person a matter of degree? What about doing harm rather than merely allowing harm? The rejection of hypersensitivity has serious implications for our views about well-being, distributive ethics, population ethics, non-consequentialist constraints and prerogatives, and other central topics in ethics. The picture I defend remains a pluralist one, but one that places surprisingly few absolute limits on tradeoffs between different evaluatively relevant factors. (For some of my earlier work on hypersensitivity, see ‘Sorites on What Matters’, ‘Spectrum Arguments and Hypersensitivity’, and ‘Lopsided Lives’.)

The Rules of Rescue: Cost, Distance, and Effective Altruism (2023) Oxford University Press

This is a book about duties to help others. When do you have to sacrifice life and limb, time and money, to prevent harm to others? When must you save more people rather than fewer? These questions arise in emergencies involving nearby strangers who are drowning or trapped in burning buildings. But they also arise in our everyday lives, in which we have constant opportunities to give time or money to help distant strangers in need of food, shelter, or medical care. With the resources available to you, you can provide more help or less. This book argues that it is often wrong to provide less help rather than more, even when the personal sacrifice involved makes it permissible not to help at all. It shows that helping distant strangers by donating or volunteering is morally more like rescuing nearby strangers than most of us realize. The ubiquity of opportunities to help others threatens to make morality extremely demanding, and the book argues that it is only thanks to adequate permissions grounded in considerations of cost and autonomy that we may pursue our own plans and projects. It concludes that many of us are required to provide no less help over our lives than we would have done if we were effective altruists.


The Priority Monster (provisionally forthcoming) Oxford Studies in Political Philosophy Volume 12

According to the Priority View, benefiting people is more morally important, the worse off these people are. This view seems plausible: if you could achieve a very large benefit for badly off Albert or instead achieve a slightly smaller benefit for much worse off Betty, it seems you should benefit Betty rather than Albert, other things being equal. But now suppose that, instead of achieving this benefit for Betty, you could achieve a slightly smaller benefit for much much worse off Carlos. Or instead a slightly smaller benefit for someone much worse off still… We can continue expanding your set of options in this fashion. For each benefit you could achieve for one person, you could instead achieve a slightly smaller benefit for someone much worse off. The final option in your set of options is achieving a tiny benefit for extraordinarily badly off Zeke. A natural interpretation of the Priority View has the counterintuitive implication that you should achieve the tiny benefit for extraordinarily badly off Zeke rather than the very large benefit for “ordinarily” badly off Albert. In response, I argue that, if P is sufficiently badly off, then no matter how much worse off Q is, priority should be given to Q over P only as a tie-breaker. This way the Priority View avoids the implication that it is of utmost moral importance that you achieve benefits for the extraordinarily badly off, even if those benefits are trifling.

Compensated Altruism and Moral Autonomy (forthcoming) Social Philosophy and Policy

It is sometimes morally permissible not to help others even when doing so is overall better for you. For example, you are not morally required to take a career in medicine over a career in music, even if the former is both better for others and better for you. I argue that the permissibility of not helping in a range of cases of “compensated altruism” is explained by the existence of autonomy-based considerations. I sketch a view according to which you can have autonomy-based permissions to choose between alternatives when these alternatives differ in terms of the valuable features they instantiate. Along the way, I argue that considerations of moral autonomy do not support rejecting the plausible view that we each constantly face reasons with morally requiring strength to help (distant) strangers.

Rescue and Necessity: A Reply to Quong (2023) Journal of Ethics and Social Philosophy 25(2): 413–419 (with Joel Joseph)

Suppose A is wrongfully attempting to kill you, thereby forfeiting his right not to be harmed proportionately in self-defense. Even if it were proportionate to blow off A’s arms and legs to stop his attack, this would be impermissible if you could stop his attack by blowing off just one of his arms. Blowing off his arms and legs violates the necessity condition on imposing harm. Jonathan Quong argues that violating the necessity condition consists in violating a right to be rescued: blowing off four of A’s limbs in proportionate self-defense rather than blowing off one of A’s limbs in proportionate self-defense fails to costlessly rescue three of A’s limbs. In response, we present cases which intuitively show that violating the necessity constraint involves the violation of a right that is more stringent than a right to be rescued.

Contrastive Consent and Secondary Permissibility (2023) Philosophy and Phenomenological Research 106(3): 677–691

Consider three cases:

Turn: A trolley is about to kill five innocent strangers. You can turn the trolley onto me, saving the five and killing me.

Hurl: A trolley is about to kill five innocent strangers. You can hurl me at the trolley, saving the five and paralyzing me.

TurnHurl: A trolley is about to kill five innocent strangers. You can turn the trolley onto me, saving the five and killing me. You can instead hurl me at the trolley, saving the five and paralyzing me.

Most find the following four claims intuitively plausible:

(1) It is permissible to turn the trolley onto me in Turn.
(2) It is impermissible to hurl me at the trolley in Hurl.
(3) It is impermissible to turn the trolley onto me in TurnHurl.
(4) It is permissible to hurl me at the trolley in TurnHurl.

But how does turning go from permissible to impermissible, and hurling from impermissible to permissible, when both alternatives are available? I argue that such “secondary permissibility” claims are explained by contrastive consent. Even if I do not consent to being harmed, it is likely I’ll consent to being hurled at the trolley rather than being turned onto.

Lesser-Evil Justifications: A Reply to Frowe (2022) Law and Philosophy 41: 639–646 (with Kerah Gordon-Solmon)

Sometimes one can prevent harm only by contravening rights. If the harm one can prevent is great enough, compared to the stringency of the opposing rights, then one has a lesser-evil justification to contravene the rights. Non-consequentialist orthodoxy holds that, most of the time, lesser-evil justifications add to agents’ permissible options without taking any away. Helen Frowe rejects this view. She claims that, almost always, agents must act on their lesser-evil justifications. Our primary task is to refute Frowe’s flagship argument. Secondarily, it is to sketch a positive case for nonconsequentialist orthodoxy.

Sorites on What Matters (2022) Ethics and Existence: The Legacy of Derek Parfit, edited by Jeff McMahan, Tim Campbell, James Goodrich, and Ketan Ramakrishnan, Oxford: Oxford University Press, pp. 498–523

Ethics in the tradition of Derek Parfit’s Reasons and Persons is riddled with sorites-like arguments, which lead us by what seem innocent steps to seemingly false conclusions. Take, for example, spectrum arguments for the Repugnant Conclusion that appeal to slight differences in quality of life. Several authors have taken the view that, since spectrum arguments are structurally analogous to sorites arguments, the correct response to spectrum arguments is structurally analogous to the correct response to sorites arguments. This sorites analogy is here argued against. There are potential structural disanalogies between spectrum arguments and sorites arguments. But even if these arguments are relevantly structurally analogous, they differ in their content in ways that show the sorites analogy to be implausible. Two content-based disanalogies are here explored—one is inspired by Parfit’s work on reductionism, and the other involves hypersensitivity. The chapter concludes with a methodological lesson.

Supererogation and Conditional Obligation (2022) Philosophical Studies 179(5): 1429–1443 (with Daniel Muñoz)

Many classic moral paradoxes involve conditional obligations, such as the obligation to be gentle if one is to murder. Many others involve supererogatory acts, or “good deeds beyond the call of duty.” Less attention, however, has been paid to the intersection of these topics. We develop the first general account of conditional supererogation. It has the power to solve both some familiar puzzles as well as several that we introduce. Moreover, our account builds on two familiar insights: the idea that conditionals restrict quantification and the idea that supererogation emerges from a clash between justifying and requiring reasons.

Impermissible yet Praiseworthy (2021) Ethics 131(4): 697–726.
— Selected by the Philosopher’s Annual as “one of the ten best articles in philosophy from 2021”

It is commonly held that unexcused impermissible acts are necessarily blameworthy, not praiseworthy. I argue that unexcused impermissible acts can not only be pro tanto praiseworthy, but overall praiseworthy—and even more so than permissible alternatives. For example, there are cases in which it is impermissible to at great cost to yourself rescue fewer rather than more strangers, yet overall praiseworthy, and more so than permissibly rescuing no one. I develop a general framework illuminating how praiseworthiness can so radically come apart from deontic status.

Rescue and Personal Involvement: A Response to Woollard (2020) Analysis 80(1): 59–66 (with Roger Crisp)

Fiona Woollard argues that when one is personally involved in an emergency, one has a moral requirement to make substantial sacrifices to aid others that one would not otherwise have. She holds that there are three ways in which one could be personally involved in an emergency: by being physically proximate to the victims of the emergency; by being the only person who can help the victims; or by having a personal encounter with the victims. Each of these factors is claimed to be defeasibly sufficient to ground personal involvement, and thus a requirement of substantial sacrifice to aid. Woollard defends this view on the basis of a number of cases. We show that Woollard’s cases contain various confounding factors. In view of the more precisely drawn cases offered here, it is clear that neither proximity nor uniqueness nor personal encounter is intuitively defeasibly sufficient in the way Woollard claims.

Effective Justice (2020) Journal of Moral Philosophy 17(4): 398–415 (with Roger Crisp)

Effective Altruism is a social movement which encourages people to do as much good as they can when helping others, given limited money, time, effort, and other resources. This paper first identifies a minimal philosophical view that underpins this movement, and then argues that there is an analogous minimal philosophical view which might underpin Effective Justice, a possible social movement that would encourage promoting justice most effectively, given limited resources. The latter minimal view reflects an insight about justice, and our non-diminishing moral reason to promote more of it, that surprisingly has gone largely unnoticed and undiscussed. The Effective Altruism movement has led many to reconsider how best to help others, but relatively little attention has been paid to the differences in degrees of cost-effectiveness of activities designed to decrease injustice. This paper therefore not only furthers philosophical understanding of justice, but has potentially major practical implications.

All or Nothing, but If Not All, Next Best or Nothing (2019) The Journal of Philosophy 116(5): 278–291 

Suppose two children face a deadly threat. You can either do nothing, save one child by sacrificing your arms, or save both by sacrificing your arms. Here are two plausible claims: first, it is permissible to do nothing; second, it is wrong to save only one. Joe Horton argues that the combination of these two claims has the implausible implication that if you are not going to save both children, you ought to save neither. This is one instance of what he calls the All or Nothing Problem. I here present conditional permissions as the solution. Although saving only one child is wrong, it can be conditionally permissible, that is, permissible given what you are not going to do. You ought to save both children or save neither, but if you are not going to save both, you ought to do the next best thing (save one) or save neither.

The Worseness of Nonexistence (2019) Saving People from the Harm of Death, edited by Espen Gamlund and Carl Tollef Solberg, New York: Oxford University Press, pp. 215–228

Most believe that it is worse for a person to die than to continue to exist with a good life. At the same time, many believe that it is not worse for a merely possible person never to exist than to exist with a good life. I argue that if the underlying properties that make us the sort of thing we essentially are can come in small degrees, then to maintain this commonly-held pair of beliefs we will have to embrace an implausible sort of evaluative hypersensitivity to slight nonevaluative differences. Avoidance of such hypersensitivity pressures us to accept that it can be worse for merely possible people never to exist. If this conclusion is correct, then the standard basis for giving no or less priority to merely possible persons would disappear (i.e., that things cannot be better or worse for them). Though defenders of Person-Affecting Views and their opponents may still disagree in theory, they could arrive at the same answers to many monumentally important practical questions.

Each-We Dilemmas and Effective Altruism (2019) Journal of Practical Ethics 7(1): 24–32 (with Matthew Clark)

In his interesting and provocative article ‘Being Good in a World of Need’, Larry Temkin argues for the possibility of a type of Each-We Dilemma in which, if we each produce the most good we can individually, we produce a worse outcome collectively. Such situations would ostensibly be troubling from the standpoint of effective altruism, the project of finding out how to do the most good and doing it, subject to not violating side-constraints. We here show that Temkin’s argument is more controversial than it may appear initially regarding both impartiality and goodness. This is because it is both inconsistent with (i) a plausible conception of impartiality (Anonymity) and inconsistent with (ii) the standard view of goodness (the Internal Aspects View). Moreover, because (i) and (ii) are entailed by the sense of ‘impartial goodness’ that effective altruism tentatively adopts, Temkin’s argument is less relevant to effective altruism than he suggests.

Spectrum Arguments and Hypersensitivity (2018) Philosophical Studies 175(7): 1729–1744

Larry Temkin famously argues that what he calls spectrum arguments yield strong reason to reject Transitivity, according to which the ‘all-things-considered better than’ relation is transitive. Spectrum arguments do reveal that the conjunctions of independently plausible claims are inconsistent with Transitivity. But I argue that there is very strong independent reason to reject such conjunctions of claims, and thus that the fact that they are inconsistent with Transitivity does not yield strong reason to reject Transitivity.

Lopsided Lives (2017) Oxford Studies in Normative Ethics 7: 275–296

Intuitively there are many different things that non-derivatively contribute to well-being: pleasure, desire satisfaction, knowledge, friendship, love, rationality, freedom, moral virtue, and appreciation of true beauty. According to pluralism, at least two different types of things non-derivatively contribute to well-being. Lopsided lives score very low in terms of some types of things that putatively non-derivatively contribute to well-being, but very high in terms of other such types of things. I argue that pluralists essentially face a trilemma about lopsided lives: they must either make implausible claims about how they compare in terms of overall well-being with more balanced lives, allow overall well-being to be implausibly hypersensitive to very slight nonevaluative differences, or else adopt implausible seeming limits on what things lives can contain or how much they can contribute to overall well-being. Such problems about lopsided lives thus push us away from pluralism and toward simpler theories of well-being, toward hedonism in particular.

Whether and Where to Give (2016) Philosophy and Public Affairs 44(1): 77–95
— Featured in a discussion at PEA Soup with a critical précis by Johann Frick 


Effective altruists recommend that we give large sums to charity, but by far their more central message is that we give effectively, i.e., to whatever charities would do the most good per dollar donated. In this paper, I’ll assume that it’s not wrong not to give bigger, but will explore to what extent it may well nonetheless be wrong not to give better. The main claim I’ll argue for here is that in many cases it would be wrong of you to give a sum of money to charities that do less good than others you could have given to instead, even if it would not have been wrong of you not to give the money to any charity at all. I assume that all the charities under discussion here do positive good overall, do not cause harm, do not infringe rights, etc. What makes my main claim here particularly interesting is that it is inconsistent with what appears to be a fairly common assumption in the ethics of giving, according to which if it is not wrong of you to keep some sum of money for yourself, then it is likewise not wrong of you to donate it to any particular charity you choose. Roughly: if it’s up to you whether to donate the money, it’s also up to you where to donate the money. I challenge this common assumption.

Does Division Multiply Desert? (2014) Philosophical Review 123(1): 43–77

It seems plausible that (i) how much punishment a person deserves cannot be affected by the mere existence or nonexistence of another person. We might have also thought that (ii) how much punishment is deserved cannot increase merely in virtue of personal division. I argue that (i) and (ii) are inconsistent with the popular belief that, other things being equal, when people culpably do very wrong or bad acts, they ought to be punished for this – even if they have repented, are now virtuous, and punishing them would benefit no one. Insofar as we cannot deny (i), we are either forced to abandon the popular belief in desert, or else allow that personal division could, as I put it, “multiply desert”. Some may not find the latter, considered by itself, troubling. But I argue that the thesis that division multiplies desert faces a potentially serious problem, which arises in the context of personal fusion. It is accordingly difficult to see how to maintain a particular family of desert views in light of the cases here presented.

Intuitions about Large Number Cases (2013) Analysis 73(1): 37–46

Is there some large number of very mild hangnail pains, each experienced by a separate person, which would be worse than two years of excruciating torture, experienced by a single person? Many people have the intuition that the answer to this question is No. However, a host of philosophers have argued that, because we have no intuitive grasp of very large numbers, we should not trust such intuitions. I argue that there is decent intuitive support for the No answer, which does not depend on our intuitively grasping or imagining very large numbers.

Edited Volumes and Special Issues

Special Issue on Effective Altruism (2024) Public Affairs Quarterly (guest editor)

Effective altruism is the project of using resources like time and money to help others as much as possible. The effective altruism social movement has been around since about 2011 and now has thousands of supporters and is backed by billions of dollars in donations. At the same time, the project, underlying philosophy, and social movement of effective altruism have attracted substantial criticism, voiced in very visible venues. The present special issue of PAQ deals with a range of philosophical issues at the heart of this ongoing public debate. Below is a very brief overview of the articles in this issue.

In “Why Not Effective Altruism?,” Richard Yetter Chappell takes a careful look at criticisms that have been offered against effective altruism. He focuses on four ideas associated with effective altruism that have received particular attention, including moral prioritization, earning to give, billionaire philanthropy, and longtermism. Chappell argues that, in each case, the core moral claims of effective altruism cannot reasonably be rejected.

In “Effective Altruists Need Not Be Pronatalist Longtermists,” Tina Rulli offers a sustained rebuttal to the argument for longtermism presented by William MacAskill in his recent book What We Owe the Future. In particular, she objects to pronatalist longtermism, which favors extensively populating the future, provided the future will be on balance good. Rulli argues that taking account of moral considerations most would recognize shows this position to be implausible. Her view is nonetheless compatible with versions of longtermism that focus on preventing harms to future people.

In “How (Not) to Fear Death,” Susanne Burri provides a fresh perspective on the ancient question of whether we should fear death. She argues that, on a wide range of theories of well-being, it can be fitting to fear death. Burri argues that having a proper philosophical understanding of our reasons to fear death is in fact essential to reducing our death-related fears. This, she argues, provides an example of philosophical therapy, a neglected type of intervention effective altruists should consider. Given that the dissemination of valuable philosophical insight is so cheap, and could significantly benefit so many, it can and should be pursued alongside more resource-intensive interventions such as distributing malaria nets or reducing existential risks.

In “Effective Altruism and Requiring Reasons to Help Others,” Thomas Sinclair provides a response to one of the main claims of my recent (2023) book The Rules of Rescue. I claim that each of us has a requiring reason (or pro tanto duty) to prevent harm to others, whenever we have the opportunity to do so. I argue that since these opportunities are ubiquitous, so, too, are requiring reasons. In response, Sinclair argues that we have requiring reasons to help others only when we engage with the plights of these others in a certain way. That engagement is not ubiquitous; it is present in cases of nearby emergency rescues, but it is not present simply whenever we can donate to effective charities.

Philosophical debates surrounding effective altruism have developed rapidly over the past decade or so. As the articles in this special issue suggest, there is still much to be explored.

Effective Altruism: Philosophical Issues (2019) Oxford University Press (co-edited with Hilary Greaves)

This is the first collective study of the thinking behind the effective altruism movement. This movement comprises a growing global community of people who organise significant parts of their lives around the two key concepts represented in its name. Altruism is the idea that if we use a significant portion of the resources in our possession—whether money, time, or talents—with a view to helping others then we can improve the world considerably. When we do put such resources to altruistic use, it is crucial to focus on how much good this or that intervention is reasonably expected to do per unit of resource expended (as a gauge of effectiveness). We can try to rank various possible actions against each other to establish which will do the most good with the resources expended. Thus we could aim to rank various possible kinds of action to alleviate poverty against one another, or against actions aimed at very different types of outcome, focused perhaps on animal welfare or future generations. The scale and organisation of the effective altruism movement encourage careful dialogue on questions that have perhaps long been there, throwing them into new and sharper relief, and giving rise to previously unnoticed questions. In this volume a team of internationally recognised philosophers, economists, and political theorists present refined and in-depth explorations of issues that arise once one takes seriously the twin ideas of altruistic commitment and effectiveness.

Popular Pieces

Saving the Many or the Few: The Moral Relevance of Numbers (2022) 1000-Word Philosophy

To your left, three strangers are drowning. To your right, one other stranger is drowning. You can effortlessly save the three by throwing a lifebuoy to your left. Alternatively, you can save the one by throwing the lifebuoy to your right. You cannot save all four. What should you do? It’s wrong to do nothing, but is it wrong to save just the one stranger? Are you morally required to save the three? Many claim that, when those you can help are innocent strangers with similar interests at stake, you’re required to save the greater number. Is this claim justified? This essay reviews some doubts.

Charity and Partiality (2019) Ethics and the Contemporary World, edited by David Edmonds, Abingdon: Routledge, pp. 121–132

Many of us give to charities that are close to our hearts rather than those that would use our gifts to do more good, impartially considered. Is such partiality to charities acceptable? I argue that if partiality to particular people is justified, we can go some distance toward justifying partiality to particular charities. Even so, partiality to charities is justified in fewer cases than most people seem to believe.

Risky Giving (2016) The Philosophers’ Magazine 73(2): 62–70

We might worry that Peter Singer’s argument from “Famine, Affluence, and Morality” is unconvincing to non-consequentialists who accept moral constraints against imposing significant risks of harm on individuals. After all, giving to overseas charities often comes with such risks. I argue that plausible non-consequentialist criteria imply that it is not wrong to give to at least some of the charities that Singer and other effective altruists recommend.

Adding Happy People (2016) Philosophers Take on the World, edited by David Edmonds, Oxford: Oxford University Press, pp. 236–239

I very briefly sketch two arguments for the claim that we have significant moral reason to ‘add happy people’ (that is, bring into existence people with lives that are well worth living), independently of any effects on those already existing. Note: I no longer believe that it is wrong not to costlessly create happy people.

Encyclopedia Entry

Effective Altruism (2020) International Encyclopedia of Ethics, edited by Hugh LaFollette (with William MacAskill)

In this entry, we discuss both the definition of effective altruism and objections to effective altruism, so defined.


Review of The Precipice: Existential Risk and the Future of Humanity, by Toby Ord (2020) Notre Dame Philosophical Reviews

Review of The Ethics of Giving: Philosophers’ Perspectives on Philanthropy (2020) Philosophical Quarterly 70(279): 426–429