For some voters, Donald Trump has provided more than enough reasons to oppose his presidential bid: Sexist and racist comments, a lack of political experience, angry late night tweets, and multiple business bankruptcies.

But for Silicon Valley leaders, a big fear is technology’s future.

“The problem is that you have a candidate whose entire rhetoric is based on going back to the old jobs,” said Box co-founder and CEO Aaron Levie on Wednesday at Vanity Fair‘s New Establishment Summit in San Francisco.

Indeed, Trump’s campaign has severely pushed the idea that economic policies, especially trade agreements, have caused a massive loss of manufacturing jobs to other countries. “We are losing jobs to other countries at a higher rate than ever,” he said during the first presidential debate last month.

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But a fixation on returning to a previous time in America’s economy—or at least, that’s what Trump claims he would do—would be a disastrous approach for the country, according to Levie, whose company provides online file storage to consumers and businesses.

“We are on the cusp of some very very fundamental disruptions of a lot of industries,” said Levie. “We have to thoughtfully navigate this,” he added. Transportation, for example, is heading toward autonomous cars, as Levie pointed out, and the nation’s leaders can’t be in denial about impending shifts.

“The future is gonna happen,” warned Levie.

And speaking of Trump, Levie also addressed investor Peter Thiel’s support for Trump. In the last few days, news that Thiel will donate $1.25 million to Trump’s campaign and allied groups raised serious debate in Silicon Valley. Following the news, startup accelerator Y Combinator’s president, Sam Altman, refused to cut ties with the investor despite being personally opposed to Trump and many of his ideas. Altman’s argument is that shunning those who have differing political views is the wrong approach.

“I think at a minimum, it would probably be good to do a temporary pause on the relationship for the sake of the organization,” said Levie, though he added that ultimately “it’s a personal decision.”