I’m still not clear on why anyone would think that the world works as indicated by SIA,
I also don’t see the appeal of SIA. As far as I know, its only selling point is that it nullifies the Doomsday Argument. But that doesn’t seem to me to be the right basis for choosing a method of anthropic reasoning.
Moreover, Katja Grace points out that even SIA implies “Doomsday” in the sense that SIA, with some reasonable assumptions, makes the Great Filter likely to be ahead of us instead of behind us. For it seems plausible that, among the universes with Great Filters, most individuals live prior to their lineage’s getting hit with the Great Filter. So, if we update on the fact that we live in a universe with a Great Filter (which follows from the Fermi Paradox), then SIA tells us to expect that our Great Filter is in our future, not in our past (as it would be if the Great Filter were something like the difficulty of evolving intelligence).
Katja agrees that this only holds if you assume we are not simulations. SIA hugely supports the simulation hypothesis, and then the SIA-Doomsday argument fails.
Hmm. It seems to me that Katja’s argument fails if huge interstellar civilizations are likely to stop other civilizations from reaching our current stage (deliberately or unwittingly), which sounds plausible to me.
It seems to me that Katja’s argument fails if huge interstellar civilizations are likely to stop other civilizations from reaching our current stage (deliberately or unwittingly), which sounds plausible to me.
Could you explain? Wouldn’t that just tell you with even greater certainty that there are no huge interstellar civilizations around, which would argue even more strongly that we live in a universe with a Great Filter? And couldn’t it still be the case that most individuals would live prior to their lineage’s encounter with the Great Filter? So, why wouldn’t Katja’s argument still go through?
ETA: Okay, I think that I see your point: If, in each universe where life arises, some civilization gets huge and nips all other life in that universe in the bud, and if the civilization gets so huge that it outnumbers the sum of the populations of all the lineages that it squelches, then it would not be the case that “most individuals live prior to their lineage’s getting hit with the Great Filter”. On the contrary, across all possible worlds, most individuals would live in one of these huge civilizations, which never get hit with a Great Filter. In that case, Katja’s argument would not go through.
I think that a lot of people don’t consider “We just happen to be the first technical civilization” to be a satisfactory solution to the Fermi paradox. It is the fact that this region wasn’t already teeming with life that points to the presence of a Great Filter.
Your proposal conjoins this response to the Fermi paradox with the further claim that we will go on to squelch any subsequent technical civilizations. So your proposal can only be less satisfying than the above response to the Fermi paradox. The problem is that, if we are going to be this region’s Great Filter, then we have come too late to explain why this region isn’t already teeming with life.
I also don’t see the appeal of SIA. As far as I know, its only selling point is that it nullifies the Doomsday Argument. But that doesn’t seem to me to be the right basis for choosing a method of anthropic reasoning.
Moreover, Katja Grace points out that even SIA implies “Doomsday” in the sense that SIA, with some reasonable assumptions, makes the Great Filter likely to be ahead of us instead of behind us. For it seems plausible that, among the universes with Great Filters, most individuals live prior to their lineage’s getting hit with the Great Filter. So, if we update on the fact that we live in a universe with a Great Filter (which follows from the Fermi Paradox), then SIA tells us to expect that our Great Filter is in our future, not in our past (as it would be if the Great Filter were something like the difficulty of evolving intelligence).
Katja agrees that this only holds if you assume we are not simulations. SIA hugely supports the simulation hypothesis, and then the SIA-Doomsday argument fails.
Hmm. It seems to me that Katja’s argument fails if huge interstellar civilizations are likely to stop other civilizations from reaching our current stage (deliberately or unwittingly), which sounds plausible to me.
Could you explain? Wouldn’t that just tell you with even greater certainty that there are no huge interstellar civilizations around, which would argue even more strongly that we live in a universe with a Great Filter? And couldn’t it still be the case that most individuals would live prior to their lineage’s encounter with the Great Filter? So, why wouldn’t Katja’s argument still go through?
ETA: Okay, I think that I see your point: If, in each universe where life arises, some civilization gets huge and nips all other life in that universe in the bud, and if the civilization gets so huge that it outnumbers the sum of the populations of all the lineages that it squelches, then it would not be the case that “most individuals live prior to their lineage’s getting hit with the Great Filter”. On the contrary, across all possible worlds, most individuals would live in one of these huge civilizations, which never get hit with a Great Filter. In that case, Katja’s argument would not go through.
Yep, that’s what I meant. I wonder if anyone raised this point before, it sounds kinda obvious.
I think that a lot of people don’t consider “We just happen to be the first technical civilization” to be a satisfactory solution to the Fermi paradox. It is the fact that this region wasn’t already teeming with life that points to the presence of a Great Filter.
Your proposal conjoins this response to the Fermi paradox with the further claim that we will go on to squelch any subsequent technical civilizations. So your proposal can only be less satisfying than the above response to the Fermi paradox. The problem is that, if we are going to be this region’s Great Filter, then we have come too late to explain why this region isn’t already teeming with life.