There aren't many people in the world who can justifiably call Mark Zuckerberg a dumb-ass, but Elon Musk is probably one of them.

Early on Tuesday morning, in the latest salvo of a tussle between the two tech billionaires over the dangers of advanced artificial intelligence, Musk said that Zuckerberg's "understanding of the subject is limited."

I won't rehash the entire argument here, but basically Elon Musk has been warning society for the last few years that we need to be careful of advanced artificial intelligence. Musk is concerned that humans will either become second-class citizens under super-smart AIs , or alternatively that we'll face a Skynet-like scenario against a robot uprising

Zuckerberg, on the other hand, is weary of fear-mongering around futuristic technology. "I have pretty strong opinions on this. I am optimistic," Zuckerberg said during a Facebook Live broadcast on Sunday. "And I think people who are naysayers and try to drum up these doomsday scenarios... I just don't understand it. It's really negative and in some ways I think it is pretty irresponsible."

Then, responding to Zuckerberg's "pretty irresponsible" remark, Musk said on Twitter: "I've talked to Mark about this. His understanding of the subject is limited."

It's a little unfair to call Zuckerberg's understanding "limited"—Facebook has arguably put a lot more time, money, and research into AI than Musk's companies. I suspect the real bone of contention between the two nerds has more to do with time scales: Zuckerberg's stance on AI is that it will massively improve the human condition (and probably Facebook ad revenues) in the short term, but Musk is more concerned with what happens further down the line, when it's too late to put the sentient robot cat back in the bag.

In reality, a balanced approach that takes a little from column M and a pinch from column Z is probably the best way forward. There is already too much momentum in the twinned domains of automation, robotics, and artificial intelligence for Musk's concerns to be taken too seriously—but that doesn't mean we have to blindly accelerate into a future powered by initially helpful Zuckbots.

Now read about how the artificial intelligence Singularity isn't just around the corner...