Philosophy › Contemporary › Applied ethics (bioethics, animals, global poverty)
Effective altruism and longtermism
2009 onward· School or movement· Ethics & how to live
Mostly agreedGood evidence; some details uncertain.
A movement that uses evidence and reason to do the most good per dollar or hour, and in its longtermist form prioritizes the far future.
See it on the Philosophy map →The idea
Idea: if you help, help as effectively as possible. Charity evaluator GiveWell (2007) ranked charities by cost per life saved, often favoring malaria nets. Oxford philosophers Toby Ord and Will MacAskill founded Giving What We Can in 2009, asking members to pledge 10% of income. Longtermism adds that future people count equally and could be vastly numerous, so cutting extinction risks such as pandemics or runaway AI may matter most. Main objection: it dresses speculative math as certainty and neglects systemic change.
Why it matters
It has steered billions of dollars to global health, animal welfare and AI safety. The 2022 collapse of FTX, whose founder was a prominent backer, badly damaged its reputation.
Where it comes from
Its founding groups, pledges and GiveWell's published cost-effectiveness analyses are public; key books are Singer's The Most Good You Can Do (2015), Ord's The Precipice (2020) and MacAskill's What We Owe the Future (2022).
Still debated
Whether longtermism's math is sound, and whether the movement drifted from proven charity toward speculative causes, is fiercely debated inside and outside it.
Connections (3)
▸Peter Singer: the drowning child and Animal Liberation inspired Effective altruism and longtermismWell documented
The connection
Singer's drowning-child argument says the well-off must give much more, and give where it helps most. Early effective altruists, such as Toby Ord, took this as a call to action. Singer then joined them, writing books on how to choose the most effective charities.
When and how
Ord and Will MacAskill founded Giving What We Can at Oxford in 2009; Singer wrote The Life You Can Save (2009) and The Most Good You Can Do (2015).
How we know
The founders cite Singer's 1972 essay as formative, and Singer became a leading public advocate, including a 2013 TED talk on effective altruism.
Debates and open questions
Singer's focus on proven poverty charities differs from the later longtermist turn; how closely the movement still follows his original argument is debated.
▸Nick Bostrom: superintelligence and the simulation argument shaped the priorities of Effective altruism and longtermismMostly agreed
The connection
Bostrom argued that human extinction would destroy not only present lives but vast numbers of possible future ones, so even slightly reducing extinction risk could outweigh most other good deeds. Effective altruists adopted this reasoning, making AI safety and pandemic prevention top causes.
When and how
Bostrom's 'Astronomical Waste' (2003) and 'Existential Risk Prevention as Global Priority' (2013), from Oxford's Future of Humanity Institute, which worked closely with early effective altruists in Oxford.
How sure are we?
Longtermist books by Ord and MacAskill cite Bostrom heavily, and major funders list AI risk as a priority, though how much is due to Bostrom alone is uncertain.
Debates and open questions
Critics argue the expected-value reasoning behind these priorities is fragile; supporters reply that ignoring small chances of catastrophe is the real mistake.
▸Derek Parfit, Reasons and Persons inspired Effective altruism and longtermismMostly agreed
The connection
Parfit argued that future people matter morally as much as present ones. He ended Reasons and Persons comparing peace, a war killing 99% of humanity, and one killing everyone: the last step is far worse, because it ends all future lives. Longtermism grew from that thought.
When and how
Reasons and Persons (1984), final chapter; Parfit's Oxford colleagues, among them Toby Ord and Will MacAskill, founded effective altruist groups there from 2009.
How sure are we?
Ord and MacAskill credit Parfit directly, and his 99% versus 100% passage is often quoted as longtermism's root, though Parfit was not a movement leader.
Debates and open questions
Parfit's own 'repugnant conclusion' shows how hard it is to value future people; whether longtermism has solved those puzzles or set them aside is debated.