• Home
  • Latest
  • Fortune 500
  • Finance
  • Tech
  • Leadership
  • Lifestyle
  • Rankings
  • Multimedia

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

By
Kirsten Korosec
Kirsten Korosec
Down Arrow Button Icon
By
Kirsten Korosec
Kirsten Korosec
Down Arrow Button Icon
December 21, 2017, 1:50 PM ET

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 Wiredpublished 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.

Idiots can be very dangerous when they seem smart, but aren’t (having “PhD” in their bio is a dead giveaway), as some policymakers may get fooled. That’s what really bothered me about that human cat meme / transit “expert”.

— Elon Musk (@elonmusk) December 21, 2017

I would only call someone an idiot if people were mistakenly under the impression that the person was smart

— Elon Musk (@elonmusk) December 21, 2017

Later, Musk took things officially too far.

His “PhD” is in literature (really), presumably bad fiction

— Elon Musk (@elonmusk) December 21, 2017

For the record, I actually love trains, most subways and London buses.

— Elon Musk (@elonmusk) December 21, 2017

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.”

However, public transit is obviously not fully solving the problem, as most major cities have been in traffic hell for decades with no solution in sight. Multi-level tunnels can solve this, but we need much better tunneling technology, as it is currently super slow and expensive.

— Elon Musk (@elonmusk) December 21, 2017

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

About the Author
By Kirsten Korosec
See full bioRight Arrow Button Icon

Latest in

AIchief executive officer (CEO)
Microsoft AI boss Suleyman opens up about his peers and calls Elon Musk a ‘bulldozer’ with ‘superhuman capabilities to bend reality to his will’
By Jason MaDecember 13, 2025
25 seconds ago
Danish military forces participate in an exercise with hundreds of troops from several European NATO members in the Arctic Ocean in Nuuk, Greenland, Monday, Sept. 15, 2025.
PoliticsDonald Trump
Danish intelligence report warns of U.S. economic leverage and military threat under Trump
By The Associated PressDecember 13, 2025
53 minutes ago
Ukrainian President Volodymyr Zelensky gives a joint press conference in Kyiv, Ukraine in 2023 as European leaders visit the country 18 months after the start of Russia's invasion.
EuropeUkraine invasion
EU indefinitely freezes Russian assets to prevent Hungary and Slovakia from vetoing billions of euros being sent to support Ukraine
By Lorne Cook and The Associated PressDecember 13, 2025
58 minutes ago
Spanish Prime Minister Pedro Sánchez often praises the financial and social benefits that immigrants bring to the country.
EuropeSpain
In a continent cracking down on immigration and berated by Trump’s warnings of ‘civilizational erasure,’ Spain embraces migrants
By Suman Naishadham and The Associated PressDecember 13, 2025
1 hour ago
EconomyAgriculture
More financially distressed farmers are expected to lose their property soon as loan repayments and incomes continue to falter
By Jason MaDecember 13, 2025
2 hours ago
Middle EastMilitary
Trump pledges retaliation after 3 Americans are killed in Syria attack that the U.S. blames on the Islamic State group
By Samar Kassabali, Bassem Mroue, Seung Min Kim and The Associated PressDecember 13, 2025
3 hours ago

Most Popular

placeholder alt text
Economy
Tariffs are taxes and they were used to finance the federal government until the 1913 income tax. A top economist breaks it down
By Kent JonesDecember 12, 2025
1 day ago
placeholder alt text
Success
Apple cofounder Ronald Wayne sold his 10% stake for $800 in 1976—today it’d be worth up to $400 billion
By Preston ForeDecember 12, 2025
1 day ago
placeholder alt text
Success
40% of Stanford undergrads receive disability accommodations—but it’s become a college-wide phenomenon as Gen Z try to succeed in the current climate
By Preston ForeDecember 12, 2025
1 day ago
placeholder alt text
Economy
The Fed just ‘Trump-proofed’ itself with a unanimous move to preempt a potential leadership shake-up
By Jason MaDecember 12, 2025
1 day ago
placeholder alt text
Economy
For the first time since Trump’s tariff rollout, import tax revenue has fallen, threatening his lofty plans to slash the $38 trillion national debt
By Sasha RogelbergDecember 12, 2025
1 day ago
placeholder alt text
Success
Apple CEO Tim Cook out-earns the average American’s salary in just 7 hours—to put that into context, he could buy a new $439,000 home in just 2 days
By Emma BurleighDecember 12, 2025
1 day ago
Rankings
  • 100 Best Companies
  • Fortune 500
  • Global 500
  • Fortune 500 Europe
  • Most Powerful Women
  • Future 50
  • World’s Most Admired Companies
  • See All Rankings
Sections
  • Finance
  • Leadership
  • Success
  • Tech
  • Asia
  • Europe
  • Environment
  • Fortune Crypto
  • Health
  • Retail
  • Lifestyle
  • Politics
  • Newsletters
  • Magazine
  • Features
  • Commentary
  • Mpw
  • CEO Initiative
  • Conferences
  • Personal Finance
  • Education
Customer Support
  • Frequently Asked Questions
  • Customer Service Portal
  • Privacy Policy
  • Terms Of Use
  • Single Issues For Purchase
  • International Print
Commercial Services
  • Advertising
  • Fortune Brand Studio
  • Fortune Analytics
  • Fortune Conferences
  • Business Development
About Us
  • About Us
  • Editorial Calendar
  • Press Center
  • Work At Fortune
  • Diversity And Inclusion
  • Terms And Conditions
  • Site Map

© 2025 Fortune Media IP Limited. All Rights Reserved. Use of this site constitutes acceptance of our Terms of Use and Privacy Policy | CA Notice at Collection and Privacy Notice | Do Not Sell/Share My Personal Information
FORTUNE is a trademark of Fortune Media IP Limited, registered in the U.S. and other countries. FORTUNE may receive compensation for some links to products and services on this website. Offers may be subject to change without notice.