Jev 名字来源：杰文斯的 1869 年「逻辑钢琴」
考据 Jev 命名不只取自杰文斯悖论，还指向杰文斯造的逻辑推理机——不做算术只做决策，正好对应 Jev 的定位。
went down a rabbit hole on why typesafe named their model jev everyone cites the jevons paradox. fair. but jevons also did something way cooler in 1869 he had a clockmaker in salford build him a "logic piano" ~3 feet tall, 21 keys, looks like a tiny upright piano. the face shows all 16 true/false combinations of 4 terms you "play" your premises on the keys. something like "all A are B" rods inside physically remove every combination that contradicts what you entered. when you're done, whatever's left on the face is your answer it was the first machine to solve logic problems faster than a human could. he demoed it at the royal society in 1870 and it's still sitting in a museum in oxford the wildest part: it wasn't a calculator. it didn't do numbers. it did decisions which is exactly what jev is. no text, just decisions 157 years later the only real upgrade is that it can say "i'm 87% sure" naming a decision model after him goes way harder than the paradox