Elon Musk Explains When He Thinks it’s Okay To Call Someone an Idiot

December 21, 2017, 6:50 PM UTC

Tesla and SpaceX CEO Elon Musk wants everyone to know that he would only call someone an “idiot” if people were mistakenly under the impression that this person is smart—oh, and he really does love most trains, subways, and London buses.

Taken out of context, Musk’s Thursday tweetstorm—which touched on all those subjects—might seem strange. But it all goes back to a fracas that erupted earlier this month after Wired published comments made by the CEO at an artificial intelligence conference. Musk said that “public transport is painful. It sucks. Why do you want to get on something with a lot of other people, that doesn’t leave where you want it to leave, doesn’t start where you want it to start, doesn’t end where you want it to end?”

Musk called the Wired report “misleading and misanthropic.” But that didn’t stop critics from lashing out at the billionaire entrepreneur’s description of shared transit as an unpleasant safety risk.

And that’s when things escalated.

Jarrett Walker, a high-profile public transit advocate and consultant, jumped into the debate, describing Musk as an elitist and calling his disdain for public transit as “a luxury (or pathology) that only the rich can afford.”

Musk’s response was short—“You’re an idiot”—and it only poured more fuel on an already fiery debate.

After the initial eruption, all seemed quiet until NYT columnist and economist Paul Krugman retweeted out a story from Fortune with one comment “Elon Musk’s idea of a cogent argument, ‘You’re an idiot.'”

It took a couple of days, but Musk fired back with a string of tweets explaining his reasoning, and declaring his love for some public transit.

Later, Musk took things officially too far.

Still, Musk says public transit doesn’t fully solve the problem “as most major cities have been in traffic hell for decades with no solution in sight.”

The upshot? Tunnels. Multi-level tunnels. Which is what his other business, The Boring Company, just happens to be pursuing.