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If there are a "handful," then there are probably 0 (besides us). You have to believe that there's a very narrow range of values to get precisely to a handful.

If there are a "handful," then there are probably 0 (besides us). You have to believe that there's a very narrow range of values to get precisely to a handful. Like, the range quoted above is from "10,000 to a few million," so a factor of 200ish from high to low range. If you think that there are 10, per galaxy, why don't you believe instead that there are 0.3 per galaxy (only off by a factor of 30?)? How much confidence can you have in your highly speculative variables that your output can be constrained down to just a single order of magnitude or so?

cgore 9y ago
By handful I mean < 5. Probably usually just one. Because no others would get a chance to evolve, with all the habitable planets quickly being occupied by whichever species figures out interstellar travel first.
- civilian 9y ago
  I think you have a very Golden-Era-of-Sci-Fi space-opera conquering view of spacefaring. Why do we need to expand? Our population growth is already levelling off. Why do we need to send _our bodies_ rather than with AI, or with our consciouses uploaded into computers? (a la Charles Stross' Accelerando or Greg Egan's Diaspora) If we're sending AI probes around, why do we need to take all resources to the extent that we prevent other species from developing? Most of the fundamental science that we want to do can be done right here in our own solar system. There's just not a need to expand.
  - voidmain 9y ago
    Once you have sufficiently advanced technology, unless you also have some kind of totalitarianism, it only takes a few groups of people who disagree about the allocation of resources (or, really, anything else) in this star system and want to leave. And then the same thing happens recursively in whatever star systems they go to, and you have exponential growth until it saturates to cubic or whatever. Yes, of course, they will be AIs or uploads or body printers. Even for an advanced civilization, shipping bags of meat to other star systems would be wasteful. That doesn't mean they won't want to use resources, or that there would be no evidence of them if they were already here. edit: There's certainly scenarios in which the first species to explore a galaxy doesn't literally prevent other species from evolving. But that doesn't mean they wouldn't be obviously detectable. The likely number of starfaring species in the galaxy given our observations is zero.
  - Fjolsvith 9y ago
    > There's just not a need to expand. It doesn't take a need, just a desire. Someone wanting to be able to say, "I went there. I saw it. I got the T-Shirt."

cgore 9y ago

By handful I mean < 5. Probably usually just one. Because no others would get a chance to evolve, with all the habitable planets quickly being occupied by whichever species figures out interstellar travel first.

civilian 9y ago
I think you have a very Golden-Era-of-Sci-Fi space-opera conquering view of spacefaring. Why do we need to expand? Our population growth is already levelling off. Why do we need to send _our bodies_ rather than with AI, or with our consciouses uploaded into computers? (a la Charles Stross' Accelerando or Greg Egan's Diaspora) If we're sending AI probes around, why do we need to take all resources to the extent that we prevent other species from developing? Most of the fundamental science that we want to do can be done right here in our own solar system. There's just not a need to expand.
- voidmain 9y ago
  Once you have sufficiently advanced technology, unless you also have some kind of totalitarianism, it only takes a few groups of people who disagree about the allocation of resources (or, really, anything else) in this star system and want to leave. And then the same thing happens recursively in whatever star systems they go to, and you have exponential growth until it saturates to cubic or whatever. Yes, of course, they will be AIs or uploads or body printers. Even for an advanced civilization, shipping bags of meat to other star systems would be wasteful. That doesn't mean they won't want to use resources, or that there would be no evidence of them if they were already here. edit: There's certainly scenarios in which the first species to explore a galaxy doesn't literally prevent other species from evolving. But that doesn't mean they wouldn't be obviously detectable. The likely number of starfaring species in the galaxy given our observations is zero.
- Fjolsvith 9y ago
  > There's just not a need to expand. It doesn't take a need, just a desire. Someone wanting to be able to say, "I went there. I saw it. I got the T-Shirt."