The Current

Why this philosopher wants you to think about your great-great-great-great-great-grandchildren — and beyond

With longtermism, philosopher William MacAskill wants us to approach today's problems with an eye on how our decisions will affect future generations, and the world they could inherit thousands of years from now.

Longtermism asks how our actions affect people in the distant future, says William MacAskill

A man stands in front of a brick wall, wearing glasses and a blue t shirt.
With longtermism, philosopher William MacAskill wants us to approach today's problems with an eye on the world that future generations could inherit thousands of years from now. (Forethought Foundation for Global Priorities Research)

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Philosopher William MacAskill has a novel argument for keeping fossil fuels in the ground: our descendants might need them to rebuild civilization after a future catastrophe.

"It's a horrific question, but if it were the case that 90 per cent of people died … and civilization got put back to pre-industrial levels of technology, would we be able to recover?" asked MacAskill, a philosophy professor at the University of Oxford and director of the Forethought Foundation for Global Priorities Research.

MacAskill said he's optimistic about human ingenuity if the worst were to happen, but asserted that as "an iron law," industrialization required large amounts of coal, oil and gas.

"We should be very worried that … civilization would collapse and we never would come back [without fuel]," he told The Current's Matt Galloway.

"In addition to the air pollution costs and in addition to the climate costs … that gives us yet another reason to just keep fossil fuels in the ground."

MacAskill considers the doomsday scenario in his new book What We Owe the Future. In it, he explores longtermism, a moral philosophy that MacAskill helped to shape and define about five years ago.

WATCH | What is longtermism?

What is longtermism?

3 months ago
Duration 1:58
Philosopher William MacAskill explains the concept of longtermism, and how our actions today could affect the vast number of humans who will live in future generations.

"Longtermism is the view that we should be doing much more to protect the interests of future generations than we currently are.… It's about trying to build a better future for those future generations," he said.

He argues that humans have existed for about 300,000 years and could exist for hundreds of thousands to come, particularly if technology gives us the ability to spread among the stars.

"The sheer scale in terms of the number of people yet to come is absolutely vast. Future generations [will] outnumber us by 1,000 to one. Maybe even more," he said.

"We should be thinking very seriously about the things that could happen in our lifetimes, that could be pivotal in terms of the longer-run trajectory of human civilization."

MacAskill said longtermism was informed by his previous work on effective altruism — a movement aimed at zeroing in on the most constructive ways to make the world a better place.

That work led him to believe that helping people anywhere in the world was as important as helping people in your own country. 

By that reasoning, "if people are equally important no matter where they are in space, well, they're equally important no matter where they are in time as well," he said.

"And so if there are things that we can do to positively impact the coming centuries or thousands of years or even longer, then we should be doing that."

MacAskill said the world is facing a slew of threats that did not exist hundreds of years ago, such as climate change and the risk of nuclear war.

Cave paintings depicting hand stencils in Spain, thought to be tens of thousands of years old. MacAskill said that humans have been around for 300,000 years, but the future of our species could extend even further than that — perhaps out into the stars. (Pedro Saura/AAAS/Associated Press)

But there are also newer risks on the horizon, such as advances in artificial intelligence, which could one day put enormous power in the hands of just a few individuals, or even a single dictator.

"If you have an automated workforce, an automated army, well, you no longer need some large coalition of people all working together in order to make society run," he said.

Instead, a dictator in control of automated forces could seize power, bypassing democratic processes, MacAskill said.

"We really should be working to mitigate these risks so that we can get the benefits of new technology without some of the dangers that new technology can pose," he said.

Longtermism 'dangerous,' says critic

Effective altruism has attracted billionaire proponents over the years, including Sam Bankman-Fried, the CEO and founder of the cryptocurrency exchange FTX. Bankman-Fried was a major donor to non-profit organizations affiliated with effective altruism.

The cover of a book that says What We Owe the Future.
MacAskill's book, What We Owe The Future. (Forethought Foundation for Global Priorities Research)

FTX is now under investigation by U.S. officials after it collapsed in bankruptcy, amid allegations of fraud.

MacAskill has not been named in the investigation, nor is there any indication he will be. But following the news he wrote on Twitter: "If FTX misused customer funds, then I personally will have much to reflect on. Sam and FTX had a lot of goodwill — and some of that goodwill was the result of association with ideas I have spent my career promoting. If that goodwill laundered fraud, I am ashamed."

Longtermism is a separate philosophy, but is not without its critics. In a 2021 essay published in the digital magazine Aeon, philosopher Émile P. Torres described the worldview as "quite possibly the most dangerous secular belief system in the world today."

Torres sees longtermism as potentially erasing the suffering of people alive today, in the pursuit of humanity fulfilling its perceived greater potential. 

Within that framework, "even a climate catastrophe that cuts the human population by 75 per cent for the next two millennia will, in the grand scheme of things, be nothing more than a small blip — the equivalent of a 90-year-old man having stubbed his toe when he was two," Torres writes.

"The harms caused to actual people, especially those in the Global South, might be significant in absolute terms. But when compared to the 'vastness' and 'glory' of our long-term potential in the cosmos, they hardly even register."

WATCH | Humanity is acting like a teenager, says philosopher

Humanity is acting like a teenager, says philosopher

3 months ago
Duration 2:01
Humanity’s reckless approach to our world is playing “Russian roulette with our future,” says philosopher William MacAskill

MacAskill said longtermism is not "primarily about making plans that will only pay off in 100 years' time," but instead is a new lens for assessing the many problems humanity faces today.

"It's about looking at near-term risks with long-term consequences," he said.

MacAskill acknowledged that people can feel paralyzed by the enormity of some of these problems. But he thinks it's possible to "make a truly enormous difference."

"If you're just sitting in that bed under the duvet, you know, the world's never going to get better," he said.

"It takes people to kind of get out of the chairs, out of the sofa, and really start to put these ideas into practice to make the world a better place."

Audio produced by Idella Sturino.

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