Artificial-intelligence (AI) machines could put one-half of the human workforce out of their jobs within three decades, a computer scientist told colleagues at an American Association for the Advancement of Science meeting in Washington.

Echoing physicist Stephen Hawking’s and technology titan Bill Gates’ warnings last year, Moshe Vardi said AI could mean the end of the human race as we know it, the Guardian reported Saturday. “We are approaching a time when machines will be able to outperform humans at almost any task,” said Vardi, a professor of computational engineering and the director of the Ken Kennedy Institute for Information Technology at Rice University. “I believe that society needs to confront this question before it is upon us: If machines are capable of doing almost any work humans can do, what will humans do?”

Cautioning that the coming change won’t be similar to one associated with the Industrial Revolution, when machines overpowered human physical capacity, Vardi said AI will challenge the human mind, with human wit competing against mechanical intelligence. Vardi warned against the type of future he is predicting, arguing a life predominantly taken up by leisure while machines do all the work is unhealthy.

“I do not find this a promising future, as I do not find the prospect of leisure-only life appealing,” Vardi said. “I believe that work is essential to human well-being.”

Meanwhile, other tech thinkers have indicated there is a future for mankind as the role of AI is expanded in our daily lives. Ray Kurzweil, an engineering director at the Google unit of Alphabet Inc., said at a conference in June that by the 2030s human brains will be able to connect to the cloud directly and access the intelligence of thousands of computers, CNN Money reported. And developers at Google have made advancements in AI, creating a self-driving car recognized as a driver in the U.S.