Few people think about artificial intelligence and its ultimate impact on humanity more than Sam Altman, CEO of ChatGPT maker OpenAI. So when Altman worries about “how people of the future will view us,” it’s worth paying attention.

In a series of tweets this weekend, Altman shared his thoughts on the dangers posed by current A.I. technology—and by the tools that will follow in the years ahead.

ChatGPT has been freaking some people out of late—particularly the ChatGPT-powered Bing, whose at times unsettling suggestions and comments have prompted OpenAI and Microsoft to try to reassure the public and better explain the technology.

Altman doesn’t seem concerned about today’s ChatGPT, but rather what’s next. He tweeted, “although current-generation AI tools aren’t very scary, I think we are potentially not that far away from potentially scary ones.”

He seemed preoccupied with time, predicting that the integration of A.I. tools into society will happen quickly—and the world needs time to adjust.

He wrote, “the adaptation to a world deeply integrated with AI tools is probably going to happen pretty quickly; the benefits (and fun!) have too much upside. We also need enough time for our institutions to figure out what to do. Regulation will be critical and will take time to figure out…having time to understand what’s happening, how people want to use these tools, and how society can co-evolve is critical.”

His thoughts also turned to how future generations will look back on this point of history and the decisions being made now—and he seemed to hope for some understanding and forgiveness.

“I wish that all generations would treat previous generations with indulgence,” he wrote. “Humanity is deeply imperfect. Our grandparents did horrible things; our grandchildren will understand that we did horrible things we don’t yet understand.”

“The people who came before us are a complete package of good and bad,” he continued, “and collectively they pushed the world forward; it’s important to view the moral progress of society as an ongoing joint project we are all responsible for. Now it’s our turn. I hope the people of the future will view us the same way.”

This week, Tesla CEO Elon Musk distanced himself from OpenAI, which he helped fund and establish as a nonprofit in 2015. Microsoft has invested heavily in OpenAI in recent years and last month indicated it will sink even more money into the venture.

On Friday, Musk tweeted, “OpenAI was created as an open source (which is why I named it “Open” AI), non-profit company to serve as a counterweight to Google, but now it has become a closed source, maximum-profit company effectively controlled by Microsoft. Not what I intended at all.”