My grandfather’s idea of an Easter egg hunt involved hiding money in colorful plastic eggs sprinkled around his house on Long Island. Most held coins, but there was always one with a crisp, new $100 bill.

My cousin, Billy-O, and I were the only players. We were usually playful partners in mayhem but as competitors, we took on every hunt with gusto, flipping over cushions, throwing open cabinets, knocking each other aside until, without fail, Billy-O found the $100.

The first time he won, I fought back tears. But after a few years of losses, I exploded.

“It’s just not fair,” I yelled.

“Life’s unfair,” my grandfather told us. “You win or you lose.”

This is what’s called zero-sum thinking — the belief that life is a battle over finite rewards where gains for one mean losses for another. And these days, that notion seems to be everywhere. It’s how we view college admissions, as a cutthroat contest for groups defined by race or privilege. It’s there in our love for “Squid Game.” It’s Silicon Valley’s winner-take-all ethos, and it’s at the core of many popular opinions: that immigrants steal jobs from Americans; that the wealthy ge