Elon Musk is no stranger to making bold statements. It's on-brand for him to say something big is going to happen sometime in the near future, contrary to most evidence or expert opinion. He's done it for autonomous vehicles,  robotics, and the Covid-19 pandemic, among many other things.

Let's take a look at his latest tweet. Musk wrote, not for the first time, that "population collapse due to low birth rates is a much bigger risk to civilization than global warming." With Musk, you never know his real MO. When he pens a 280-character essay, does he actually believe what he's writing? Or is it more for show? Is it to get people, like myself, to write a reaction piece that talks about Musk so he can get more media coverage? 

There's part of me that believes it's all a stunt. He knows it'll work in his favor to make such bold claims because, well, as the old saying goes, there's no such thing as bad publicity. That's especially true for the world's richest person.

But just for a moment, let's assume he's doing it in good faith. Let's give him the benefit of the doubt: Elon Musk truly believes, in this case, that one of the biggest threats to humans is population decline, more so than climate change.

Is Musk onto something?

First off, let's fact-check his statement.

Demographic and population experts shut it down quickly. "He's better off making cars and engineering than at predicting the trajectory of the population," said Joseph Chamie, a demographer and former director of the UN Population Division.

As Chamie and his expert colleagues have shown in their detailed work (which you can find in peer-reviewed journals, not Twitter), the trajectory of the human population is a nuanced point of discussion, involving matters of fertility rates versus death rates, global health care and medicine, cultural norms, and immigration patterns. All that to say, Musk's prediction about population decline is just flat-out wrong. 

Elon Musk has an IQ of 155, which makes him a genius, technically. So why then does a really smart person say such dumb things, assuming it's not a publicity stunt? 

When smart people have bad ideas

In his book Think Again, psychologist Adam Grant talks about how intelligence is typically seen as the basis for sound judgment and effective learning. We assume that the smarter you are, the closer to the truth you get. But intelligence, especially analytical intelligence, is no cure for biased and inaccurate beliefs. It can even be a curse: "There's evidence that being good at thinking can make us worse at rethinking. The brighter we are, the blinder to our own limitations we can become." 

People, like Musk, are adept at using numbers and figures to support their opinion. In their mind, they have the data to back up their arguments. And, often, they talk fast in serving up a rebuttal. They probably tweet at record speeds, too. 

Research has also shown that people who learn outside their field of expertise start off with a sense of intellectual humility, but as they begin to learn more, they become "unconscious incompetents" -- not knowing what they don't know. 

All of this leads to a false confidence in what they believe. It is a perfect portrayal of Elon Musk. Do we believe what he has to say about population decline? As with many of his tweets, we should probably take it with a large grain of salt.