Will MacAskill

Quick Facts

• Full name: William David MacAskill
• Born: 1987, Glasgow, Scotland
• Field: moral philosophy, practical ethics, decision theory
• Main roles: public advocate of effective altruism; co-founder of Giving What We Can, 80,000 Hours, the Centre for Effective Altruism, and the Global Priorities Institute
• Main ideas: effective altruism, earning to give, cause prioritization, moral uncertainty, longtermism
• Major books: Doing Good Better, Moral Uncertainty, What We Owe the Future

The Big Question

MacAskill asks: if you want to help others, how should you choose what to do when your time, money, and attention are limited?

His answer is that good intentions are not enough. We should compare ways of helping by their real effects. A dollar, an hour, or a career choice can do very different amounts of good depending on where it goes. The hard part is not just caring. The hard part is choosing well.

In One Minute

Will MacAskill is a Scottish moral philosopher best known for helping build Effective Altruism and Longtermism. Effective altruism says we should use evidence and careful reasoning to help others as much as we can. That means asking uncomfortable practical questions: Which charities save the most lives per dollar? Which career paths let a person do the most good? Which global problems are huge, solvable, and neglected?

MacAskill first became famous for arguing that some people could do more good by "earning to give": taking a high-paying job and donating a large share of their income to highly effective charities. He later became a major public voice for longtermism, the view that future people matter morally and that today's choices may shape the lives of vast numbers of people who do not yet exist.

His work is not just about charity. It is about priority-setting under uncertainty. We often do not know which moral theory is right, which cause will work, or how the future will unfold. MacAskill thinks that is a reason to reason more carefully, not a reason to give up.

What They Taught

MacAskill taught that helping others should be treated as a serious practical problem. If two charities both ask for money, the question is not only which one feels moving. It is also which one produces the most benefit with the same resources. If one charity can prevent malaria deaths cheaply and another charity does much less per dollar, then the difference matters morally.

This view inherits a lot from Peter Singer. Singer argued that distance does not erase moral responsibility. A child dying far away still matters. MacAskill adds a more comparative, institutional style: if we accept that strangers matter, we should ask which actions actually help them most.

The core method is cause prioritization. A "cause" is a broad problem area, such as global health, factory farming, pandemic prevention, or artificial intelligence safety. To prioritize causes, effective altruists often ask about scale, neglectedness, and tractability. Scale means how large the problem is. Neglectedness means how few resources are already aimed at it. Tractability means whether extra effort is likely to make progress. A disease that harms millions, gets little funding, and has cheap treatments will usually rank higher than a popular cause where extra money changes little.

MacAskill also argues for moral uncertainty. Moral uncertainty means uncertainty about what morality itself requires. You might be partly convinced by Utilitarianism, which says we should promote overall welfare. But you might also think rights, promises, personal relationships, or fairness matter in ways utilitarianism can miss. MacAskill's point is that moral decision-making should not pretend this uncertainty disappears. If you are unsure whether animals matter nearly as much as humans, or unsure how much to sacrifice for distant strangers, you still need some way to act.

Longtermism extends the same reasoning to future generations. Future people are people who could exist if humanity survives and builds decent societies. MacAskill argues that they matter even though they are not here yet. If a factory pollutes a river and harms children born fifty years later, the delay does not make the harm morally invisible. Longtermism applies that thought on a much larger scale. If present choices affect whether civilization survives, whether powerful technologies are used well, or whether values become locked in, then present people may have an unusual responsibility.

This connects MacAskill to Derek Parfit, who made future people and population ethics central problems in modern ethics. Population ethics asks how to value choices that affect who exists, how many people exist, and how good their lives are. MacAskill also draws on Nick Bostrom, especially the idea of existential risk. An existential risk is a danger that could destroy humanity or permanently ruin its long-term potential.

Key Ideas With Examples

• Effective altruism: Use evidence and reason to do as much good as possible. Example: instead of donating to the nearest charity by habit, compare charities by cost, evidence, and expected benefit.
• Earning to give: Choose a high-earning career partly so you can donate more to effective causes. Example: a software engineer might donate a large share of income to malaria prevention. MacAskill treats this as one possible route, not as permission to do harmful work just because the salary is high.
• Cause prioritization: Compare whole problem areas before choosing projects. Example: if pandemic preparedness is huge, underfunded, and improvable, it may deserve more attention than a crowded cause where extra help has little effect.
• Impartiality: Give equal moral weight to people regardless of nationality, distance, or familiarity. Example: a stranger's preventable death abroad is not less real because you will never meet them.
• Moral demandingness: The worry that a theory asks too much from ordinary people. Example: if you can always donate more to save lives, does morality leave room for family, rest, art, or personal projects?
• Moral uncertainty: Act while unsure which moral theory is true. Example: if you are unsure how much animal suffering matters, you might give animal welfare some serious weight instead of ignoring it.
• Longtermism: Future people matter, and the long-term future may be shaped by today's choices. Example: preventing an engineered pandemic could protect people alive now and also preserve the possibility of many future lives.
• Lock-in: A bad system can become very hard to change once institutions or technologies make it stable. Example: a powerful AI system designed around cruel or authoritarian values could make reform much harder later.

Major Works

• Doing Good Better (2015): MacAskill's public introduction to effective altruism. The book argues that people should ask not just "How can I help?" but "How can I help the most?" It discusses charity evaluation, career choice, ethical consumption, and cases where common ways of doing good have less impact than expected.
• Moral Uncertainty (2020, with Krister Bykvist and Toby Ord): A more technical philosophy book about how to act when you are unsure which moral theory is correct. It argues that decision-making under moral uncertainty needs its own rules, much as ordinary decision-making under factual uncertainty does.
• What We Owe the Future (2022): MacAskill's major statement of longtermism. The book argues that future generations deserve moral concern, that the future could contain enormous value, and that the present may be an unusually important time for reducing catastrophic risks and shaping humane institutions.
• Founding organizations: MacAskill's practical influence also comes through Giving What We Can, 80,000 Hours, the Centre for Effective Altruism, the Global Priorities Institute, and Forethought. These organizations turn the theory into donation pledges, career advice, research programs, and public debate.

Why It Matters

MacAskill matters because he helped make an old moral demand feel operational. Many philosophers had said that distant strangers matter. MacAskill helped turn that into tools: charity comparisons, career advice, cause rankings, research agendas, and public arguments about future generations.

His work also shows the strength and danger of moral quantification. Counting lives saved can expose waste and sentimentality. It can also make moral life look too narrow if only measurable outcomes count. That tension is why MacAskill is important even for readers who reject effective altruism. He forces the question: when you say you want to do good, how carefully are you willing to ask whether your method works?

Proponents, Critics, and Opponents

Supporters see MacAskill as one of the clearest public philosophers of practical beneficence. Beneficence means helping others and preventing harm. They think effective altruism gives moral seriousness to donations, careers, and institutions that otherwise run on habit, emotion, or prestige.

Critics argue that effective altruism can be too individualistic. It often asks what one donor or worker should do at the margin, while critics want more attention to political power, labor, history, and structural injustice. A critic might say that cheap malaria nets matter, but so do public health systems, trade rules, and democratic institutions.

Other critics focus on personal relationships and integrity. MacAskill's impartial reasoning can make it look morally suspect to favor a local cause, a friend, or a community you know well. Critics reply that moral life is not only a spreadsheet of equal units. It also includes loyalty, responsibility, and the meaning of acting from your own place in the world.

After the collapse of FTX in 2022, criticism became sharper but should be stated carefully. FTX founder Sam Bankman-Fried had been associated with effective altruism and promised large donations. The scandal did not show that malaria prevention, animal welfare, or pandemic preparedness are bad causes. It did raise serious questions about movement governance, dependence on wealthy donors, trust inside tight networks, and whether "maximize expected good" language can be misused to excuse reckless behavior. MacAskill and other effective altruists have said that fraud and harm to innocent people cannot be justified by promised future donations. Critics still argue that the movement needed stronger guardrails earlier.

MacAskill is also usefully compared with John Rawls. Rawls asks what fair institutions owe to citizens, especially the least advantaged. MacAskill asks how impartial agents can do the most good with scarce resources. Both care about moral seriousness, but they begin from different pictures of ethics: fair social structure for Rawls, high-impact help and global priority-setting for MacAskill.

Related Pages

• Peter Singer
• Derek Parfit
• Nick Bostrom
• Utilitarianism
• Effective Altruism and Longtermism
• John Rawls