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> You might as well say that gravity has nothing to do with up and down. To be pedantic, gravity has nothing to do with “up” or “down”, it’s just the attractio

> You might as well say that gravity has nothing to do with up and down. To be pedantic, gravity has nothing to do with “up” or “down”, it’s just the attraction of two or more masses relative to one another. “Up” or “down” is perspective. If someone on the South Pole is looking up and someone on the North Pole is looking down, an argument could be made that the person on the South Pole is actually looking down.

quadrangle 5y ago
This is really tangential, but "up" and "down" are completely meaningless without gravity. Literally, without gravity, "up" doesn't exist. "Up" is literally just "away from the primary gravitational pull". People on either pole looking away from the planet are both looking up. That's what "up" is. It's funny to realize that two people can look "up" in opposite directions, but that's what's going on. Neither of them is looking "down", even though each one is looking in the direction of the other person's down.
- randmeerkat 5y ago
  “From our experiments, the presence of gravity appears to be a sufficient condition to evoke up/down biases in interceptive responses, at least in some subjects. It is not, however, a necessary condition. Indeed, it is thought that a network of connections involving the insulae and temporoparietal junction of the brain integrates a variety of sensory modalities to define an up/down reference frame and then tunes fast interceptive responses within that context (Indovina et al., 2005).” https://www.jneurosci.org/content/32/6/1969 https://www.jneurosci.org/content/32/6/1969 TLDR; Up and Down is just perception and has nothing to do with gravity.
  - quadrangle 5y ago
    Up and down are perceptions that we evolved specifically to indirectly sense gravity. "nothing to do with" is wrong, it's like saying that thermometers have nothing to do with temperature because various versions of them can get miscalibrated and are really visual devices.
    - randmeerkat 5y ago
      > Up and down are perceptions that we evolved specifically to indirectly sense gravity. I disagree. We evolved to orient ourselves in the environment that we operate in. Does a giant squid perceive up / down based on gravity or pressure differences in the water depth..? > it's like saying that thermometers have nothing to do with temperature I also disagree with this analogy. Gravity is a force of nature, unlike a thermometer which is a human invention to describe one’s environment.
      - quadrangle 5y ago
        I don't know how squids perceive things, but obviously water pressure is correlated with gravity in their case. There's no way to have up and down without gravity. It's meaningless. It's not that gravity can't exist without up and down. Gravity exists independently of anyone perceiving anything. But up and down do not exist without gravity. Either up and down are the perception of gravity, even though indirectly through our perceptual mechanisms, or they don't exist and have no meaning.
        randmeerkat 5y ago
        If you’re in a room with no windows in space in zero gravity with a table glued to one of the “floors” you’ll perceive anything else as being up, because up / down is a perception that exists outside of gravity. When people discuss the gravitational pull of the moon on the earth no one discusses whether or not the moon is facing up or down.
        quadrangle 5y ago
        I don't really disagree enough to bother arguing. But my thermometer analogy is still the same. You can create situations in which thermometers do indeed show something that actually is an indication of something and that something isn't heat. Thermometers are used to measure heat though. Anyway, I'll just accept your points. When I tried to think of an analogy that was as silly as "inflation has nothing to do with price" I failed. I can't think of anything as wrongly silly apparently.
- jwarden 5y ago
  In a 3D world without gravity, something like “up” and “down” would exist, just as left and right, and forward and backwards would still exist. You need some sort of label for each direction on each axis of orientation.

quadrangle 5y ago

This is really tangential, but "up" and "down" are completely meaningless without gravity. Literally, without gravity, "up" doesn't exist. "Up" is literally just "away from the primary gravitational pull". People on either pole looking away from the planet are both looking up. That's what "up" is. It's funny to realize that two people can look "up" in opposite directions, but that's what's going on. Neither of them is looking "down", even though each one is looking in the direction of the other person's down.

randmeerkat 5y ago
“From our experiments, the presence of gravity appears to be a sufficient condition to evoke up/down biases in interceptive responses, at least in some subjects. It is not, however, a necessary condition. Indeed, it is thought that a network of connections involving the insulae and temporoparietal junction of the brain integrates a variety of sensory modalities to define an up/down reference frame and then tunes fast interceptive responses within that context (Indovina et al., 2005).” https://www.jneurosci.org/content/32/6/1969 https://www.jneurosci.org/content/32/6/1969 TLDR; Up and Down is just perception and has nothing to do with gravity.
- quadrangle 5y ago
  Up and down are perceptions that we evolved specifically to indirectly sense gravity. "nothing to do with" is wrong, it's like saying that thermometers have nothing to do with temperature because various versions of them can get miscalibrated and are really visual devices.
  - randmeerkat 5y ago
    > Up and down are perceptions that we evolved specifically to indirectly sense gravity. I disagree. We evolved to orient ourselves in the environment that we operate in. Does a giant squid perceive up / down based on gravity or pressure differences in the water depth..? > it's like saying that thermometers have nothing to do with temperature I also disagree with this analogy. Gravity is a force of nature, unlike a thermometer which is a human invention to describe one’s environment.
    - quadrangle 5y ago
      I don't know how squids perceive things, but obviously water pressure is correlated with gravity in their case. There's no way to have up and down without gravity. It's meaningless. It's not that gravity can't exist without up and down. Gravity exists independently of anyone perceiving anything. But up and down do not exist without gravity. Either up and down are the perception of gravity, even though indirectly through our perceptual mechanisms, or they don't exist and have no meaning.
      - randmeerkat 5y ago
        If you’re in a room with no windows in space in zero gravity with a table glued to one of the “floors” you’ll perceive anything else as being up, because up / down is a perception that exists outside of gravity. When people discuss the gravitational pull of the moon on the earth no one discusses whether or not the moon is facing up or down.
        quadrangle 5y ago
        I don't really disagree enough to bother arguing. But my thermometer analogy is still the same. You can create situations in which thermometers do indeed show something that actually is an indication of something and that something isn't heat. Thermometers are used to measure heat though. Anyway, I'll just accept your points. When I tried to think of an analogy that was as silly as "inflation has nothing to do with price" I failed. I can't think of anything as wrongly silly apparently.
jwarden 5y ago
In a 3D world without gravity, something like “up” and “down” would exist, just as left and right, and forward and backwards would still exist. You need some sort of label for each direction on each axis of orientation.