Mark Zuckerberg and Elon Musk disagree on AI

Tesla (TSLA) and Space X CEO Elon Musk and Facebook (FB) CEO Mark Zuckerberg, two richest, most successful people on Earth, are beefing. Okay, they’re not exactly beefing — it’s more like they’re having a very public disagreement on social media for the whole world to see.

In a tweet posted Tuesday, Musk accused Zuckerberg of having a limited understanding of artificial intelligence.

The comment comes after Zuckerberg criticized Musk in a Facebook Live video calling the Tesla founder’s stance that AI poses an “existential threat” to mankind “pretty irresponsible.”