• LibertyLizard@slrpnk.net
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    9 days ago

    I think this speaks to a significant misunderstanding that most people hold of the way vision actually works.

    Most people imagine that vision is a relatively simple process by which our eyes detect and transmit to us the nature of the world. Not so.

    Eyes are complex and interesting organs in their own right but fundamentally what they do is relatively simple. They are able to detect and report to the brain certain qualities of the light that hits them. Primarily these are: intensity, direction, and proximity to three points on the frequency spectrum (what we perceive as red, green, and blue). But this data alone is not vision. Vision is a conscious experience our brains create by interpreting and processing this data into the visual field before us—basically, a full scale 3D model of the world in front of us, including the blended information on reflection and emission that color entails.

    Quite amazing! Most of this takes place in the human brain, and not the eyes. From this perspective, it is not terribly surprising that an organism with more complex eyes but a much simpler brain might have worse vision than we do.

    • GreenCavalier@lemmy.ca
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      8 days ago

      Ha! I read the following Science new article just today about how Purple Only Exists In Our Brains. It’s written for a younger audience (I think), but it lays out how our sight works, and how our brains trick us into seeing purple (a red-blue colour, as opposed to violet).

      Poor shrimpos, no purple for them, I bet.

      • cholesterol@lemmy.world
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        7 days ago

        This phrasing always bothers me a little, because, as even the article quotes a scientist saying: “All colors are made up by the brain.”

        Purple is special because it triggers from non-continuous wavelengths of light, not because the subjective experience of purple is an invention of the brain. Being ‘invented’ is something common to all colors. Or sounds. Or tastes.

        • pcalau12i@lemmygrad.ml
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          11 hours ago

          Color is not invented by the brain but is socially constructed. You cannot look inside someone’s brain and find a blob of green, unless idk you let the brain mold for awhile. All you can do is ask the person to think of “green” and then correlate whatever their brain patterns are that respond to that request, but everyone’s brain patterns are different so the only thing that ties them all together is that we’ve all agreed as a society to associate a certain property in reality with “green.”

          If you were an alien who had no concept of green and had abducted a single person, if that person is thinking of “green,” you would have no way to know because you have no concept of “green,” you would just see arbitrary patterns in their brain that to you would seem meaningless. Without the ability to reference that back to the social system, you cannot identify anything “green” going on in their brain, or for any colors at all, or, in fact, for any concepts in general.

          This was the point of Wittgenstein’s rule-following problem, that ultimately it is impossible to tie any symbol (such as “green”) back to a concrete meaning without referencing a social system. If you were on a deserted island and forgot what “green” meant and started to use it differently, there would be no one to correct you, so that new usage might as well be what “green” meant.

          If you try to not change your usage by building up a basket of green items to remind you of what “green” is, there is no basket you could possibly construct that would have no ambiguity. If you put a green apple and a green lettuce in there, and you forget what “green” is so you look at the basket for reference, you might think, for example, that “green” just refers to healthy vegetation. No matter how many items you add to the basket, there will always be some ambiguity, some possible definition that is compatible with all your examples yet not your original intention.

          Without a social system to reference for meaning and to correct your mistakes, there is no way to be sure that today you are even using symbols the same way you used them yesterday. Indeed, there would be no reason for someone born and grew up in complete isolation to even develop any symbols at all, because they would just all be fuzzy and meaningless. They would still have a brain and intelligence and be able to interpret the world, but they would not divide it up into rigid categories like “green” or “red” or “dogs” or “cats.” They would think in a way where everything kind of merges together, a mode of thought that is very alien to social creatures and so we cannot actually imagine what it is like.

    • LanguageIsCool@lemmy.world
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      8 days ago

      It’s amazing and crazy to think, too, that the “theater” our brains create is an equilibrium point of laziness (to save energy) and usefulness (to help survival). So, surely, there are things we are just unable to see. But also, probably, there are different things that get mapped to the same things in the “theater.” I’m just speculating though but it makes sense.

      • Schmoo@slrpnk.net
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        8 days ago

        It’s a good thing we can surpass the limitations of our perception by creating external tools that augment our senses and translate extra-sensory information about the world into something human perceptible. We’ve even gone so far as to send such devices into space.

    • WolfLink@sh.itjust.works
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      9 days ago

      We don’t really detect direction of light exactly. Instead we detect the location in the eye where the light landed, and have lenses to focus the light onto our retina. That relationship does imply some of the directionality of the light, by ignoring light that goes in certain directions and relating the direction of light that does get detected to the location it ends up.

      • Tlaloc_Temporal@lemmy.ca
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        9 days ago

        By the same logic, we don’t detect light, just the change in shape of certain proteins. The sky isn’t blue, it’s a subset of sunlight. We don’t really touch things, we transmit forces with tiny magnets. Computers don’t really do math, they just arrange states in certain ways.

      • LibertyLizard@slrpnk.net
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        9 days ago

        Yeah I was trying to avoid those details. I think it’s fair to summarize that as a system that detects the direction light is coming from.

      • mranachi@aussie.zone
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        8 days ago

        *we detect the direction of light by the location in the eye…ect.

        There fixed it for you.