“Do you believe your parents about how old you are?” says Marian suddenly.

Robert takes a long time to answer, but that’s why Marian asked him. “I believe my birth certificate,” he says.

“But who says that’s yours?” she says. “It’s a record purely by fiat. And consensus. Both of which could be lies.”

“Some people really don’t know their birthdays. Adopted kids, refugees.”

Marian quiets at that.

“In the old orphanages, they’d all share the same day,” he presses. “See, they didn’t have parents to disbelieve–”

“All right,” she says.

They just sit and wait for the bus after that.