“Hanson et al.’s basic model might be wrong in that expansionist alien civilizations could generally converge to be quiet, in the sense of not being clearly visible; or at least some fraction of expansionist civilizations could be quiet (both possibilities are excluded by Hanson et al.’s model).”
A large part of our main paper considers the ratio of quiet to loud aliens, and allows that ratio to be very large. Thus it is not at all true that that we ignore the possibility of many quiet civs. We also explicitly consider the possibility that we haven’t yet noticed large expansive civs, and we calculate the angle lengths of borders we might see in the sky in that case.
Thus it is not at all true that that we ignore the possibility of many quiet civs.
But that’s not the claim of the quoted text, which is explicitly about quiet expansionist aliens (e.g. expanding as far and wide as loud expansionist ones). The model does seem to ignore those (and such quiet expansionists might have no borders detectable by us).
“Hanson et al.’s basic model might be wrong in that expansionist alien civilizations could generally converge to be quiet, in the sense of not being clearly visible; or at least some fraction of expansionist civilizations could be quiet (both possibilities are excluded by Hanson et al.’s model).”
A large part of our main paper considers the ratio of quiet to loud aliens, and allows that ratio to be very large. Thus it is not at all true that that we ignore the possibility of many quiet civs. We also explicitly consider the possibility that we haven’t yet noticed large expansive civs, and we calculate the angle lengths of borders we might see in the sky in that case.
But that’s not the claim of the quoted text, which is explicitly about quiet expansionist aliens (e.g. expanding as far and wide as loud expansionist ones). The model does seem to ignore those (and such quiet expansionists might have no borders detectable by us).
A similar critique has been made in Friederich & Wenmackers’ article “The future of intelligence in the Universe: A call for humility”, specifically in the section “Why FAST and UNDYING civilizations may not be LOUD”.