Norm and Yardstick

Fen frowned. "But surely one is enough? If I know how often, isn't that the whole answer?"

"Watch what happens with only one," Norm said. She wrote a figure on the notice: seven. "Seven of something happened. I can tell you it happens seven times most weeks — so it's completely usual, by frequency." Yardstick tipped his head. "But Norm's base rate still can't tell you if seven is a lot of the thing — seven out of ten is nearly all; seven out of ten thousand is almost none. That needs my question: compared to what total? Seven can be 'basically everything' or 'basically nothing,' and how often it happens doesn't settle which." Norm nodded. "And my base rate needs his reference right back. 'Usual' compared to a calm year is different from 'usual' compared to a stormy one. Alone, each of us leaves the number half-lost."

Fen's nose twitched. "So a number I'm handed with neither — just a bare 'seven, and isn't that shocking' —"

"— is a number stripped of both partners on purpose," Yardstick finished, "precisely so your fear supplies them for it. A figure with no base rate and no reference borrows whatever size your worry gives it. That's not information; it's a costume." Norm ran a claw down her counts. "So you dress it properly. First mine: how often does this usually happen? Then his: compared to what — out of how many, next to which fair baseline? Two questions, and the seven stops being a jolt and becomes a fact — maybe a reassuring one, maybe a genuinely serious one, but now a true-sized one either way."

They had each learned their half young, and learned the hard way that half wasn't enough. Norm, a pup, had shrieked invasion at five beetles that turned out to wander in every morning — a fright cured by a base rate. Yardstick, a fledgling, had believed a mile-wide lake was the vastest water in the world until he crossed it in a lazy minute — a fright cured by a reference. But it was a single figure at the Tribune that taught them to stand together: a count that Norm proved perfectly usual by frequency, which Yardstick then showed was an enormous share of a tiny whole — usual and important at once. "One of us alone would have gotten it wrong," Norm admitted. "I'd have called it fine; he'd have missed that it was routine." Old Veritas had set them side by side after that. "A number has two ways of being misunderstood," the mentor said, "so it takes two guardians. Never let one of you pass judgement without the other. Together you give a figure back its honest size — no larger to feed a fear, no smaller to soothe one."