William MacAskill

Also known as Will MacAskill, William Crouch

William MacAskill is a Scottish moral philosopher who helped start the effective altruism movement and now works on how the world should prepare for advanced AI. Born William Crouch in Glasgow in 1987, he completed an Oxford DPhil in 2014 and co-founded Giving What We Can, 80,000 Hours and the Centre for Effective Altruism between 2009 and 2012. As an associate professor at Oxford from 2015 to 2024, he wrote Doing Good Better and What We Owe the Future, the 2022 book that made the case for longtermism. After leaving Oxford in 2024, he joined Forethought, and his 2025 paper with Fin Moorhouse, "Preparing for the Intelligence Explosion", argued that AI able to accelerate research could drive a century of technological progress in a few years. He is a senior research fellow there, writing about AI character, risk-averse AIs and what a good society after superintelligence could look like.

Now at: Forethought
Born: 1987
Badges: Founder
Boomerang

Years link to their sources.

Timeline

1987–2014

Cambridge and an Oxford DPhil

Born William Crouch in Glasgow, Scotland, in 1987, he earns a BA in philosophy at Jesus College, Cambridge in 2008 and a BPhil at St Edmund Hall, Oxford in 2010. He completes a DPhil at St Anne's College, Oxford in 2014 with a thesis on normative uncertainty, supervised by John Broome and Krister Bykvist.
2009–2012

Giving What We Can and 80,000 Hours

In November 2009, he launches Giving What We Can with Toby Ord and Bernadette Young, encouraging people to pledge 10% of their income to effective charities. As part of building the effective altruism movement, he co-founds 80,000 Hours with Benjamin Todd in 2011 to advise people on using their careers to do the most good, and the Centre for Effective Altruism in 2012.
2015

Oxford and Doing Good Better

After a junior research fellowship at Emmanuel College, Cambridge, he becomes an associate professor at the University of Oxford in 2015, with a fellowship at Lincoln College. Random House publishes his book Doing Good Better in July 2015 as a primer on the effective altruism movement.
2017–2020

The Global Priorities Institute

He co-founds the Global Priorities Institute at Oxford in 2017 and chairs its advisory board. In 2018, he gives a TED talk on effective altruism in Vancouver, and in 2020 he co-authors the book Moral Uncertainty with Krister Bykvist and Toby Ord.
2022

What We Owe the Future

Basic Books publishes What We Owe the Future in August 2022; the book makes the case for longtermism, which he defines as "the idea that positively influencing the long-term future is a key moral priority of our time." He is also a member of the FTX Future Fund, which grants $160 million to effective altruism causes in 2022, and he resigns with the rest of its team after FTX goes bankrupt.
2024–2025

Preparing for the intelligence explosion

He leaves his Oxford associate professorship in 2024 and becomes a senior research fellow at Forethought, a research nonprofit focused on the transition to a world with superintelligent AI systems. In March 2025, he and Fin Moorhouse publish "Preparing for the Intelligence Explosion," which argues that AI able to accelerate research could drive a century of technological progress in a few years and raise grand challenges such as AI-enabled autocracies and digital beings worthy of moral consideration.
January 2026–March 2026

Viatopia and AI character

In January 2026, he publishes "Viatopia," an essay on an intermediate state of society that is on track for a near-best future after superintelligence. In March 2026, he and Tom Davidson argue in "The importance of AI character" that how obedient, honest, cooperative or altruistic AI systems are will have a big effect on society.
As of October 2026

Senior research fellow at Forethought

He is a moral philosopher and senior research fellow at Forethought, working on what he calls AGI preparedness. In April 2026, on the 80,000 Hours podcast, he argues for training superintelligent AI systems to be very risk averse and paying them for their work. In June 2026, he and Elliott Thornley publish "Risk-Averse AIs," which proposes training AIs to treat resources as having diminishing marginal utility so that misaligned systems could be paid to cooperate.