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The fact that there is at least one intelligent civilization in "the" universe is not necessarily that informative. This depends on the number of universes. If

by gpsx 8y ago

The fact that there is at least one intelligent civilization in "the" universe is not necessarily that informative. This depends on the number of universes. If there is only one universe, then it is informative. If there are many universes, the probability of life in one can still be very small but it can still arise, in some universes. The question then is if there is life on our universe.

millstone 8y ago
Talking about the number of universes feels like talking about the number of wheels on a unicycle. The count is one. Either the "multiple universes" are causally disconnected and therefore irrelevant, or are actually connected and therefore part of the same universe.
- gpsx 8y ago
  Yes, these are not causally connected, so we can call the different universes. I interpreted the original post to be saying that if life is very improbable then it is unlikely we would be here. And If there were only one universe then yes, it would be unlikely we are here. But if there are many universes, this could support a vanishingly small probability of life with most universes being empty, but a small fraction having life. So these different universes are meaningful only to the extent you are asking philosophical questions like this, but not to most practical considerations.
- vidarh 8y ago
  It's a argument about how close to 0 the probability of life might be, given that we know of one instance of life. It is tempting, because we exist, to assume the probability of life arising can't be that low. But if life is so rare that the odds of one arising in any given (causally disconnected) universe means life almost never arises, and more than one civilisation is unimaginable more rare than that again, if you imagine an infinite number of universes there will still be an infinite number of civilisations. But being alone might be the most likely scenario if life is present, and nobody would be present in the empty universes to take them into account. In which case our existence might easily trick us into over-estimating the odds of life arising. Framed in a less depressing way: It might be we're not seeing the aliens because something is preventing us from observing them rather than because they don't exist.

by gpsx 8y ago

millstone 8y ago

Talking about the number of universes feels like talking about the number of wheels on a unicycle. The count is one. Either the "multiple universes" are causally disconnected and therefore irrelevant, or are actually connected and therefore part of the same universe.

gpsx 8y ago
Yes, these are not causally connected, so we can call the different universes. I interpreted the original post to be saying that if life is very improbable then it is unlikely we would be here. And If there were only one universe then yes, it would be unlikely we are here. But if there are many universes, this could support a vanishingly small probability of life with most universes being empty, but a small fraction having life. So these different universes are meaningful only to the extent you are asking philosophical questions like this, but not to most practical considerations.
vidarh 8y ago
It's a argument about how close to 0 the probability of life might be, given that we know of one instance of life. It is tempting, because we exist, to assume the probability of life arising can't be that low. But if life is so rare that the odds of one arising in any given (causally disconnected) universe means life almost never arises, and more than one civilisation is unimaginable more rare than that again, if you imagine an infinite number of universes there will still be an infinite number of civilisations. But being alone might be the most likely scenario if life is present, and nobody would be present in the empty universes to take them into account. In which case our existence might easily trick us into over-estimating the odds of life arising. Framed in a less depressing way: It might be we're not seeing the aliens because something is preventing us from observing them rather than because they don't exist.