Zuckerberg, Facebook’s CEO, wrote a post Tuesday evening in which he shared his optimism over the rise of AI technologies like deep learning and how they could lead to breakthroughs in areas like healthcare and self-driving cars.

Normally, this wouldn’t be noteworthy, considering it’s pretty obvious Zuckerberg views the rise of AI through rose-tinted glasses. The CEO has made AI a big priority for his company by hiring one of the pioneers of deep learning, Yann LeCun, as its AI research chief. Zuckerberg also created a special Facebook unit whose mission is to incorporate cutting-edge AI research into its products, and his company regularly releases research papers that highlight progress Facebook is making in AI.

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Given that the Facebook (FB) CEO is clearly a believer in AI, why is he going further out of his way to express enthusiasm over the technology, when his company’s actions speak loudly enough?

Left unsaid by Zuckerberg were recent comments made by Elon Musk on Tuesday in which the Tesla (TSLA) and SpaceX (SPACEX) CEO publicly called out Zuckerberg over what Musk believes is the Facebook CEO’s “limited” understanding of AI. Zuckerberg’s Tuesday comments also included a reference to a new Facebook AI paper that won an award at a “top computer vision conference,” as if to point to Musk that he has more than a “limited” understanding of the tech.

I've talked to Mark about this. His understanding of the subject is limited.

— Elon Musk (@elonmusk) July 25, 2017

Musk’s comments came following a recent live Facebook broadcast in which Zuckerberg criticized people who believe that AI will cause “doomsday scenarios.”

“I think people who are naysayers and try to drum up these doomsday scenarios — I just, I don’t understand it,” Zuckerberg said at the time. “It’s really negative and in some ways I actually think it is pretty irresponsible.”

Zuckerberg comments didn’t specifically single out Musk, who recently caused headlines when he told members of the National Governor’s Association that AI is “the greatest risk we face as a civilization.” Musk even told the attendees a similar hypothetical situation he shared in a documentary by filmmaker Werner Herzog in which he said AI could potentially lead to wars if used unethically.

“If you were a hedge fund or private equity fund and you said, ‘Well, all I want my AI to do is maximize the value of my portfolio,'” Musk said in the documentary, “then the AI could decide, the best way to do that is to short consumer stocks, go long defense stocks, and start a war.”

But Zuckerberg doesn’t dwell on the “bad” like Musk does, and by focusing on AI’s negative effects, the Facebook CEO believes Musk is doing a disservice in conjuring doom-and-gloom images in people’s minds.

Many other AI experts share Zuckerberg’s beliefs, as a recent Wired story on Musk’s comments indicates. “Many of us have tried to educate him and others like him about real vs. imaginary dangers of AI, but apparently none of it has made a dent,” Pedro Domingos, a University of Washington machine-learning professor told Wired.

Although Zuckerberg and Musk will likely continue trading barbs over their views on AI, the one thing they can both agree on is that the technology has become fundamental to their respective businesses.

Tesla’s self-driving cars, for example, won’t be able to improve in their capabilities without continued advances in machine learning. Meanwhile, Facebook’s various recommendation services are also incorporating AI to better predict what people want to read and watch. Whether it’s good or bad that tech giants like Facebook, Google, and even Tesla are hiring some of best AI talent and hoarding people’s data to improve their services depends on how you view that glass of water.