Eccentric entrepreneur Elon Musk didn’t mince his words when talking about renowned linguist and cognitive scientist Noam Chomsky on social media. Chomsky has criticized Musk’s neurotechnology projects in the past.

The SpaceX and Tesla boss shared a list titled “7 Things Every Kid Needs to Hear” on Twitter. One entry read “Communism has failed every time it was tried.” In a follow-up tweet, Musk wrote “Side note: Chomsky sucks.”

Agreeing with Musk, behavioral psychologist Gad Saad tweeted that Chomsky “has uttered insane things about politics for 5+ decades.” Musk responded with “He is a mind virus for fools.”

The tweet drew a split response from commenters. Some asked Musk to explain his negative views on the philosopher. “Again name calling instead of rational criticism,” one wrote.

Chomsky, who is widely considered a leading intellectual of the Left, did not respond to the attacks from Musk. The two have clashed in the past, with the businessman labeling Chomsky the “Iago of socio-economic theory” last year.

A renowned linguistics professor emeritus at MIT, Chomsky has been openly skeptical about the prospects of Musk’s neurotechnology company Neuralink. Musk has claimed that his project could help to develop non-verbal mind-to-mind communication in the not-so-distant future. Chomsky did not share his confidence.

“Trying to find out what I’m thinking… there’s no way of developing technology because we don’t understand how to proceed,” he said in 2017.

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