In a recent interview with Quartz, Gates said that a robot tax could finance jobs taking care of elderly people or working with kids in schools, for which needs are unmet and to which humans are particularly well suited. He argues that governments must oversee such programs rather than relying on businesses, in order to redirect the jobs to help people with lower incomes. The idea is not totally theoretical: EU lawmakers considered a proposal to tax robot owners to pay for training for workers who lose their jobs, though on Feb. 16 the legislators ultimately rejected it.

“You ought to be willing to raise the tax level and even slow down the speed” of automation, Gates argues. That’s because the technology and business cases for replacing humans in a wide range of jobs are arriving simultaneously, and it’s important to be able to manage that displacement. “You cross the threshold of job replacement of certain activities all sort of at once,” Gates says, citing warehouse work and driving as some of the job categories that in the next 20 years will have robots doing them.