Inspired by a post in this thread. It is suggested that a blind person would not see anything, their vision would be nothingness. Is this actually true?
For our purposes I think it’s best to consider only people who have been born without eyes or had them removed. I know most who are considered blind can actually see something.
But when I google the subject, all I really get is people in the same position as me. Asking the question on a forum.
I once read (in a work of fiction) about the agony of this guy going blind being that just couldn’t stand the brightness of it. That being blind was like staring at a white screen. Not black. It was fiction and it was a guy who lost his vision, not that was born blind.
ETA: I wonder if it is something like the phantom limbs experienced by amputees.
I don’t fit the profile asked for, but I am totally blind in my left eye. What I see with it is a featureless dark gray background. It doesn’t change whether my eyes are open or closed or it’s daylight or dark.
The weird thing is when I go from a brightly lit room into a dark one. Because my good eye suddenly goes dark, I have a strange sensation that I can see with the bad one, I guess because it hasn’t been impaired by the lack of light. It usually results in me walking into a piece of furniture, because nope, still blind.
My knowledge of the eye and the brain is severely limited (hence asking the question). But it would seem to me that the default ‘transmission’ would be blackness/greyness if there was no light.
What you describe, Bill Door (sorry to hear about that), seems to point towards the idea that even if your eyes really didn’t work, you don’t actually experience ‘nothingness’.
I wonder, if for someone who was born without (operable) eyes would be able to describe what they ‘see’ anyway. They might describe the blackness (or whiteness?) as nothing. Indeed, we often define it as ‘nothing’.
My great-grandmother, who turned blind in her old age, also spoke of a white wall.
Maybe there are two kinds of blindness, one where your photoreceptors (or the nervous system interfacing them with your brain) don’t work at all and thus you see darkness, and one where they are permanently stuck at 11 and thus you see plain white ? I’ll follow this thread with curiosity, can’t wait for the actual docs to chime in.
I too wonder how people who are born blind, and therefore have no frame of reference, i.e. no idea what “white” is, or even what seeing feels like, would describe their own condition.
In a perfectly dark room, random misfiring of neurons will result in a dark grey color, not pitch black, IIRC. So I wouldn’t be surprised if with missing eyes/damage to the optical nerve, there were still the same misfirings, and hence a similar color.
Semi-related: I know there’s a professor at MIT using lasers to try and engineer and recircuit the brain so you could, for instance, use cameras instead of eyes to see. So we might not have to worry about this question too much longer. Neat stuff.
Without turning to look, without remembering or imagining what it looks like, what does the world look like to you right now, behind you? It doesn’t look black, does it (or white, or whatever), it doesn’t look like anything. Maybe it is like that for your blind person.
People who have damage to part of their primary visual cortex are effectively blind in part of their visual field. Also, all of us naturally have a blind spot in each or our retinas, where the optic nerve connects the eye to the brain. If you are looking in a certain direction and something appears right where your blind spot is you won’t see it. Likewise for the people with partial damage due to the sort of brain damage I mentioned. However, neither of these sorts of “blind spot” are experienced as blank areas, or black (or anything else) in the visual field. They are like what is behind us, we don’t see there, but we don’t miss it either because no (working) part of the brain is expecting visual information from that area.
[On the other hand, people who become entirely blind due to brain damage (as opposed to eye or peripheral nerve issues) will, in some cases, insist that they can see perfectly well, and apparently make up stuff about what they are seeing, even though they clearly cannot see, and walk into things and so forth. It is called Anton’s syndrome: very weird.]
It might be worth adding that, as I understand it, people who are totally blind from birth are actually pretty rare. Most blind people either have some limited visual function (even if it is just being able to tell daylight from darkness), or else they became blind due to accident or disease after having been able to see earlier in their life, or most often, both. Such people presumably have some idea of what it is to see, so they are likely to be aware of what they are missing in a way that a totally congenitally blind person would not be.
I agree with the general point that you’re making, but it isn’t true that we see nothing in the blind spot.
Actually our brains try to fill in the blind spot, using data from the surrounding areas of the visual field.
It’s fascinating the kinds of guesses that this visual system makes. It can’t complete faces for example, but it can fill in repeating patterns.
I have a friend who has been totally blind since birth. This question came up on the boards once before, and I asked him about what he could perceive, visually. He said you might as well ask me (or any one of you) what we can see with our big toe.
A friend of mine lost an eye in a golfing accident. His response in pretty much the same except he inserts a rude term for the penis instead of big toe.
I have wondered in the past what a blind person taking LSD would “see”, if colors would manifest, etc.
I once fell headlong from a few meter high structure, and after a couple of seconds I came to senses, and walked away. I didn’t know I broke my arm pretty bad. But what happened was that the grass was like glowing red, with little green shiny tussocks. And all of a sudden, my vision disappeared. As of agony, I went down to my knees and said “I’m blind…!” After about ten seconds or so, my vision slowly came back, and was normal.
The thing is, that it didn’t go black, white or anything else, it just disappeared. It is impossible to describe. It was very frightening.
Hmm, interesting, except I don’t think that is so. When I was a photographer, in the darkroom when I had to load film into film holders (for a Speed Graphic), I turned off all the red iights, as needed total darkness. No matter how long it took, all I ever saw was total darkness, never grey.
I have thought of it this way: Imagine that there’s an alien race that has a sensory organ in the back of their heads that perceives “omega rays.” This sense gives them a great amount of information about their surroundings, and when they come to earth they can perceive many things that we can’t. Discovering that we don’t have this sense, one of them asks, “How would you describe your lack of perception of omega rays?”
The old “one eyed giant” 
You don’t even have to postulate aliens. We do in fact have animals right here on earth with senses we don’t have. Sharks, for instance, are electroreceptive; they have organs that allow them to sense electromagnetic fields. This is a very, very advanced sense in a shark - some can sense the electromagnetic fields given off my animals that are buried in sand. Many types of snake, including rattlesnakes, have “infravision” provided by their loreal pits (hence “pit viper.”)
So, since you guys are missing those organs, what are you perceiving right now in terms of electromagnetism? Infravision?
You think you see something in the blind spot. You don’t actually see there. If there is something there that is different from the surround, you will not see it.
I don’t think that’s equivalent to blindness (or deafness, or CIPA…). In the case of electromag fields, we don’t have organs to perceive them whatsoever, nor is a part of our noggin set aside to interpret the data provided by said inexistant organs.
However, a missing sense that does exist in the average human could be a different feeling - because we do have a significant portion of the brain whose job it is to interpret visual data. Oddness is bound to happen if that particular chain breaks.
BTW, since someone mentioned phantom limbs upthread, and since the video illustrates what I mean by “missing link, oddness ensues”, here’s a fascinating lectureabout the human brain and how it seems to work. The stuff about phantom limbs begins a 9:55, but the whole thing is definitely worth a watch.
Yes, but that part has been trained, grown, wired in the way it has to be. It will have been reused for other purposes; or rather, it never got set up for sight in the first place. Think of it as software becoming hardware: our brains aren’t hardwired for sight any more than they are hardwired for English. The structure that can eventually learn to see or to understand specific languages is there, but without the adequate input it just doesn’t work. Same as my computer’s CPU doesn’t spend resources on “recording input from the webcam” when the webcam isn’t on, and that means more CPU available for other stuff, the brain of someone whose webcams are always off simply has never, ever, used any parts to interpret visual images. The neural pathways depend on what we’ve been doing.