Alien-wise, most of the probability-mass not in the "Great Filter" theory is in the "they're all hiding" theory, right? Are there any other big events in the outcome space?
I intuitively feel like the "they're all hiding" theories are weaker and more speculative than the Great Filter theories, perhaps because including agency as a "black box" within a theory is bad, as a rule of thumb.
But, if most of the proposed candidates for the GF look weak, how do the "they're all hiding" candidates stack up? What is there, besides the Planetarium Hypothesis and Simulationism? Are there any that don't require a strong Singleton?
Theories other than "Deliberately Hiding";
Colonizing the galaxy is a crazy thing to do take one: Informational / economic network effects and the absolute lightspeed limit make advanced civilizations quite extremely reluctant to spread out - Civilizations of billions that have collapsed into single hive-cities / computational structures. This is, strictly speaking a variation on hiding, except that the stealth isn't the point, it is a side effect. Colonizing other star systems means dooming yourself to abject cultural, social and material povert...
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