"Fine, I failed the quiz," Dev said the next day. "But come on. There's still a rich world and a poor world. Us and them. That part is real."

Here is the idea, plain and up front. Rosling calls that thinking the gap instinct, and it is wrong.

The world does not split into two groups. Most of humanity lives in the middle, right where Dev's gap was supposed to be.

"Prove it," he said.

"Okay. Picture the world by income. You're imagining two humps, right? Poor pile, rich pile, empty space between."

"Basically, yes."

"That picture was roughly true in 1965. Not now. Today it's one big hump, and the bulge is in the middle."

Rosling replaced the two boxes with four income levels. Not two worlds. Four steps on a ladder.

"Level 1 is extreme poverty," I said. "About a dollar a day. You walk barefoot to fetch water. You cook over a fire. Roughly one billion people."

"Level 2?"

"About four dollars a day. You might own a bicycle and sandals. Gas for cooking. Your kids go to school. Around three billion people."

"Level 3?"

"Sixteen dollars a day. Running water. A motorbike. Maybe savings. Around two billion."

"And level 4 is us."

"Thirty-two dollars a day or more. A car, hot water, a vacation sometimes. About one billion people."

"Wait," Dev said. "Add that up. Five billion people are on levels 2 and 3?"

"Five billion. Most humans are in the middle. The gap you picture is where most people actually live."

"So why do I picture two worlds?"

"Because from level 4, everything below looks the same. Rosling has a great line about that. Stand on top of a skyscraper and you can't tell if the buildings below are one story or ten. They all look short from up there."

Dev thought about it. "So when I say poor world, I'm lumping together someone with no shoes and someone with a motorbike and a savings account."

"Exactly. Their lives are completely different. Moving from level 1 to level 2 changes everything. A bicycle. A stove. A school."

"And calling both of them poor?"

"Erases the biggest improvement in human history."

The gap instinct is our love of drama. Two groups fighting, us versus them, developed versus developing.

It makes a good story. It just does not match the data.

"Rosling even asked his students where most people live," I said. "Low income countries, middle, or high. Most guessed low."

"And the answer?"

"Middle income countries. About seventy-five percent of humanity."

"Seventy-five percent," Dev repeated. "Three out of four people."

"Three out of four. The gap is mostly empty. The middle is packed."

"Okay, but the words are everywhere," Dev said. "Developing world. Third world. The West and the rest."

"And Rosling says retire them. When the labels were invented, they sort of fit. Now they describe a world that no longer exists. Like calling your phone a car phone."

The move: catch yourself the next time you split anything into two boxes. Rich and poor. Us and them.

Then ask two questions. Where is the majority, and is the gap actually empty? Most of the time, the middle is where the action is.

Dev stared at the four levels I'd sketched on a napkin.

"Five billion people in the middle," he said. "Buying stoves and bicycles and school uniforms. That's the biggest business story on Earth and I've never seen a headline about it."

"You won't. Nobody films a family buying their first refrigerator."

He tapped the napkin. "But hang on. If billions of people climbed out of poverty, if the middle is this crowded and this busy, why does the news feel like a countdown to the end of the world?"

So if most people are in the middle, why does everything feel like it is falling apart? Rosling has an answer, and it is hiding in your news feed right now.