OpenAI CEO Sam Altman says artificial intelligence could become smarter than humans sooner than many people expect.

In a blog post on his personal site, Altman discussed what he’s calling the Intelligence Age and said “It is possible that we will have superintelligence in a few thousand days (!); it may take longer, but I’m confident we’ll get there.”

Of course, “thousands” of days is pretty open-ended. 2,000 days is 5.5 years, while 5,000 days is just shy of 14, so while Altman is incredibly bullish on AI’s future, he’s not predicting overnight changes.

Whereas generative AI’s goal is to match the intellectual capabilities of humans, superintelligent AI looks to go even further, perhaps vastly outpacing the human brain’s ability to assess problems and arrive at decisions. It’s a technology that can stoke some of the biggest fears about AI given its potential.

Altman, in his post, said society currently stands at the start of what he calls “The Intelligence Age,” which he believes can be among the most transformative in human history.

“I believe the future is going to be so bright that no one can do it justice by trying to write about it now; a defining characteristic of the Intelligence Age will be massive prosperity,” he wrote. “Although it will happen incrementally, astounding triumphs – fixing the climate, establishing a space colony, and the discovery of all of physics – will eventually become commonplace. With nearly-limitless intelligence and abundant energy – the ability to generate great ideas, and the ability to make them happen – we can do quite a lot.”

While he was bullish on the future of AI, Altman did note the risk of downsides, including the impact on the labor market, but hedged that, saying, “most jobs will change more slowly than most people think” and that many of the jobs we do today will look like wastes of time in the future.

“Nobody is looking back at the past, wishing they were a lamplighter,” he wrote.