I’ve never been a fan of Davos, that annual gathering of the rich and fatuous. One virtue of the pageant of preening and self-importance, however, is that it brings out the worst in some people, leading them to say things that reveal their vileness for all to see.

And so it was for Steven Mnuchin, Donald Trump’s Treasury secretary. First, Mnuchin doubled down on his claim that the 2017 tax cut will pay for itself — just days after his own department confirmed that the budget deficit in 2019 was more than $1 trillion, 75 percent higher than it was in 2016.

Then he sneered at Greta Thunberg, the young climate activist, suggesting that she go study economics before calling for an end to investment in fossil fuels.

Well, unearned arrogance is a Trump administration hallmark — witness Mike Pompeo, the secretary of state, claiming that a respected national security reporter couldn’t find Ukraine on a map. So it may not surprise you to learn that Mnuchin was talking nonsense and that Thunberg almost certainly has it right.