The long-term impact of artificial intelligence is one of the most hotly debated topics in Silicon Valley. Nvidia CEO Jensen Huang predicts that every job will be transformed—and likely lead to a 4-day workweek. Other tech titans go even further: Bill Gates says humans may soon not be needed “for most things,” and Elon Musk believes most humans won’t have to work at all in “less than 20 years.”

While those predictions might sound extreme, they’re not just plausible, they’re likely, said Geoffrey Hinton—the British computer scientist widely known as the “Godfather of AI.” The transition, he warned, could trigger a sweeping economic reshuffling that leaves millions of workers behind.

“It seems very likely to a large number of people that we will get massive unemployment caused by AI,” Hinton said in a recent discussion with Senator Bernie Sanders (I-VT) at Georgetown University.

“And if you ask where are these guys going to get the roughly trillion dollars they’re investing in data centers and chips… one of the main sources of money is going to be by selling people AI that will do the work of workers much cheaper. And so these guys are really betting on AI replacing a lot of workers.”

Hinton has grown increasingly vocal about what he sees as Big Tech’s misplaced priorities. The industry, he recently told Fortune, is driven less by scientific progress than by short-term profits—fueling a push to replace human workers with cheaper AI systems.