5 ms·

Maybe there has been some sort of accident of scale, like the intergalactic fleet in Hitch Hiker Guide to the Galaxy that arrives to destroy Earth but is eaten

Maybe there has been some sort of accident of scale, like the intergalactic fleet in Hitch Hiker Guide to the Galaxy that arrives to destroy Earth but is eaten by a dog. There could be a banging ET party going at the Planck scale and we would never know, they might as well be on the other side of the universe.

godelski 6y ago
The problem with this is that mechanics is not scale invariant. This puts bounds on creatures. Unless there's some crazy different way to compute I wouldn't expect a being to be able to have strong cognitive functions and be the size of a fly. They would also have a difficult time building advanced machinery to get to galactic travel scales. Similarly I wouldn't expect a creature the size of a Brontosaurus to become space faring. Because of their sizes they would have to consume significantly more resources to build simple things. A two story house probably couldn't be created out of wood or other basic biological materials making it difficult to transition into even the stone age. They also require higher food because energy requirements aren't linear. But think how much it costs to send a pound to space. Their first to space would be significantly more expensive. This doesn't mean these things are impossible because maybe there are ways around them, but it certainty shifts the probabilities by quite a bit. Given our current understanding of biology and mechanics it makes it much more probable for creatures to be within the ballpark of our size (let's say crow to elephant?).
- PaulDavisThe1st 6y ago
  I think this is a mistaken way of thinking in general, because you're omitting time. Your assuming that intelligent/thinking/conscious creatures would necessarily function on timelines that make sense to us. If that were true, then what you're saying makes sense - there are real bounds on how fast you can move chemical energy from A to B, for example. But I see nothing preventing intelligent life from operating on massively longer timescales. This requires, of course, that you believe that intelligence (and maybe consciousness too) is substrate and timescale independent, which may or may not be a big ask depending on where you stand on these issues.
  - godelski 6y ago
    I think this is strange thinking because it breaks our laws of physics. The clock ticks at the same rate in internal reference frames, it is only different when looking at two different frames. But if you're talking about them acting at slower speeds or faster, then that brings along other problems similar to the mechanics ones we discussed (assuming we're not counting that they are in a slower reference frame). It really shifts the probabilities around. Even trees act relatively quickly because forces act fast. You'd have to be in a pretty extreme environment for other things to happen. As to chemistry, if they are moving faster then that means that they have more thermal energy. That comes with radiative problems (why humans stand) and this is much more difficult the smaller you are because you have less surface area. Which then puts large energy requirements on intake. And then the inverse is true. The thing is that aliens would still have to follow the laws of physics. There is no reason to expect that wouldn't be true and reasoning otherwise would take some pretty extraordinary evidence and probably win you several Nobel prizes.
    - ChainOfFools 6y ago
      https://archive.org/details/OnBeingTheRightSize-J.B.S.Haldane https://archive.org/details/OnBeingTheRightSize-J.B.S.Haldan...
      - godelski 6y ago
        I'm sorry, you dropped a 130 page book with no other comment. Is there anything specific you want to say?
        ChainOfFools 6y ago
        sorry, the relevant part of the book is in the first few pages of the first chapter, where JBS Haldane discusses the physical limits of mammalian anatomy due to load bearing constraints on bone cross sections and hydraulic implications for a heart that must circulate blood/lymph through a gigantic body, and how all of these and other separate systemic envelopes merge to form what we understand as the "right" sizes for living things etc. Some portion of this chapter is occasionally excerpted to deflate claims about extraordinarily large or small purported alien creatures, though Haldane was setting up an argument for dynamically limited systems in general. I thought it might be an interesting skim given the similarities to your comment above.
- LargoLasskhyfv 6y ago
  Have you heard of https://en.wikipedia.org/wiki/Portia_(spider) https://en.wikipedia.org/wiki/Portia_(spider)? Or that birds brains are "wired" more dense, like our cerebellum?
  - godelski 6y ago
    I haven't, that's pretty cool. You can update my terrible range guesstimate accordingly. Though that doesn't change the main thesis of there being more likely sizes than others.

godelski 6y ago

The problem with this is that mechanics is not scale invariant. This puts bounds on creatures. Unless there's some crazy different way to compute I wouldn't expect a being to be able to have strong cognitive functions and be the size of a fly. They would also have a difficult time building advanced machinery to get to galactic travel scales. Similarly I wouldn't expect a creature the size of a Brontosaurus to become space faring. Because of their sizes they would have to consume significantly more resources to build simple things. A two story house probably couldn't be created out of wood or other basic biological materials making it difficult to transition into even the stone age. They also require higher food because energy requirements aren't linear. But think how much it costs to send a pound to space. Their first to space would be significantly more expensive. This doesn't mean these things are impossible because maybe there are ways around them, but it certainty shifts the probabilities by quite a bit. Given our current understanding of biology and mechanics it makes it much more probable for creatures to be within the ballpark of our size (let's say crow to elephant?).

PaulDavisThe1st 6y ago
I think this is a mistaken way of thinking in general, because you're omitting time. Your assuming that intelligent/thinking/conscious creatures would necessarily function on timelines that make sense to us. If that were true, then what you're saying makes sense - there are real bounds on how fast you can move chemical energy from A to B, for example. But I see nothing preventing intelligent life from operating on massively longer timescales. This requires, of course, that you believe that intelligence (and maybe consciousness too) is substrate and timescale independent, which may or may not be a big ask depending on where you stand on these issues.
- godelski 6y ago
  I think this is strange thinking because it breaks our laws of physics. The clock ticks at the same rate in internal reference frames, it is only different when looking at two different frames. But if you're talking about them acting at slower speeds or faster, then that brings along other problems similar to the mechanics ones we discussed (assuming we're not counting that they are in a slower reference frame). It really shifts the probabilities around. Even trees act relatively quickly because forces act fast. You'd have to be in a pretty extreme environment for other things to happen. As to chemistry, if they are moving faster then that means that they have more thermal energy. That comes with radiative problems (why humans stand) and this is much more difficult the smaller you are because you have less surface area. Which then puts large energy requirements on intake. And then the inverse is true. The thing is that aliens would still have to follow the laws of physics. There is no reason to expect that wouldn't be true and reasoning otherwise would take some pretty extraordinary evidence and probably win you several Nobel prizes.
  - ChainOfFools 6y ago
    https://archive.org/details/OnBeingTheRightSize-J.B.S.Haldane https://archive.org/details/OnBeingTheRightSize-J.B.S.Haldan...
    - godelski 6y ago
      I'm sorry, you dropped a 130 page book with no other comment. Is there anything specific you want to say?
      - ChainOfFools 6y ago
        sorry, the relevant part of the book is in the first few pages of the first chapter, where JBS Haldane discusses the physical limits of mammalian anatomy due to load bearing constraints on bone cross sections and hydraulic implications for a heart that must circulate blood/lymph through a gigantic body, and how all of these and other separate systemic envelopes merge to form what we understand as the "right" sizes for living things etc. Some portion of this chapter is occasionally excerpted to deflate claims about extraordinarily large or small purported alien creatures, though Haldane was setting up an argument for dynamically limited systems in general. I thought it might be an interesting skim given the similarities to your comment above.
LargoLasskhyfv 6y ago
Have you heard of https://en.wikipedia.org/wiki/Portia_(spider) https://en.wikipedia.org/wiki/Portia_(spider)? Or that birds brains are "wired" more dense, like our cerebellum?
- godelski 6y ago
  I haven't, that's pretty cool. You can update my terrible range guesstimate accordingly. Though that doesn't change the main thesis of there being more likely sizes than others.