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If robots are going to take over human jobs, that means fewer people will be working, which in turn means fewer people will be paying taxes.

And that’s a problem, since taxes fund things that are important, like schools and roads and fire departments.

Bill Gates has an idea for solving this deficit: Have the robots that take human jobs pay their share in taxes.

“Right now, the human worker who does, say, $50,000 worth of work in a factory, that income is taxed and you get income tax, Social Security tax, all those things,” said Gates in an interview with Quartz’s Editor in Chief Kevin Delaney published today. “If a robot comes in to do the same thing, you’d think that we’d tax the robot at a similar level.”

Gates says that once automation takes over activities that humans used to do, that should free up time for people to “do a better job of reaching out to the elderly, having smaller class sizes, helping kids with special needs.” All of which, Gates says, require human levels of empathy and currently suffer from a shortage of people who are able to fill those roles.

“But you can’t just give up that income tax, because that’s part of how you’ve been funding that level of human workers,” Gates said.

The tax money could come from the savings companies get from not having to pay and support human workers, or it could come from a tax on the robot companies themselves, said Gates.

Fifty percent of jobs done by humans today are vulnerable to replacement by robots, according to a McKinsey report from January. That could amount to a loss of about $15 trillion in wages worldwide and about $2.7 trillion in the United States. But the report further mentions that this might not happen until 2055, plus or minus 20 years.

“People should be figuring it out,” said Gates. “It is really bad if people overall have more fear about what innovation is going to do than they have enthusiasm. That means they won’t shape it for the positive things it can do.”

Watch the full interview from Quartz here:

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