Blind people see blackness?

[PIT2]

Do blind people see blackness?

(and before u say, "no theyre blind", please think about it!)

 

[Dragonfall]

If we define "see darkness" to be "not seeing anything", then they do see darkness, and hence under normal circumstances we never see darkness but, say, $$\epsilon$$ unit of light for some $$\epsilon >0$$.

In addition, we can say that blind people see darkness continuously, and we only see darkness periodically, assuming that light is made up of dimensionless particles and time is continuous.

 

[PIT2]

And what about animals without any eyes, do they see blackness aswell?
Do plants?

Just wondering...

 

[hypnagogue]

My guess would be that blind people don't experience visual blackness, or anything in the visual modality for that matter. For instance, a better analogue for the visual experience of a blind person (at least one blind from birth, I'd imagine) might be not blackness, but rather, the same visual experience you have of the area in the back of your head. Blackness is a visual experience, even though it usually connotes absence of light. What you see at the back of your head is more like complete absence of any visual experience at all.

Of course, that's just conjecture. The best way to answer the question would be to ask someone who was born blind but later had vision restored.

 

[PIT2]

With 'the blind from birth' part, u mean that when one hasnt ever experienced light, then one still sees blackness but doesn't realize it because one can't compare it with light (since one can't imagine what light looks like).

And for people who have not been blind from birth, they can compare their no-light-blackness to their memories of once experienced light.

So in short: what turns nothingness (no light) into somethingness(blackness), is the experience of light.

Though people who haven't been blind from birth may also experience this as nothingness, they are atleast capable of turning it into blackness if they tried hard enough. Perhaps with some trying, we non-blind people could also turn the back of our head into blackness.

 

[Mk]

My guess would be that blind people don't experience visual blackness, or anything in the visual modality for that matter. For instance, a better analogue for the visual experience of a blind person (at least one blind from birth, I'd imagine) might be not blackness, but rather, the same visual experience you have of the area in the back of your head. Blackness is a visual experience, even though it usually connotes absence of light. What you see at the back of your head is more like complete absence of any visual experience at all.

Yeah, same here. Its like asking "what do deaf people hear?" Completely blind people, can't see anything. Not even black.

 

[dav2008]

I imagine it would depend why they are blind. I don't know much about the reasons for blindness but I imagine it can either be caused by the eyes or by the brain.

If the eyes themselves are damaged then it would be the same as you being in a very dark room, that is no photons are hitting your eyes so the eyes don't send any signals to the brain and you "see" darkness.

If it's part of the brain that's damaged then I guess they wouldn't see anything. It would be as if they don't have the sense of sight at all.

 

[hypnagogue]

With 'the blind from birth' part, u mean that when one hasnt ever experienced light, then one still sees blackness but doesn't realize it because one can't compare it with light (since one can't imagine what light looks like).

It's not necessarily that simple. The visual cortex requires proper visual inputs and motoric interactions in the world on the basis of that visual input in order to develop properly. In the absence of such input from birth, visual cortex proper would likely be subsumed for other perceptual/cognitive processes. I find it unlikely that such a radically different "visual" cortex would support anything like the subjective experience of vision (of which blackness is a type).

And for people who have not been blind from birth, they can compare their no-light-blackness to their memories of once experienced light.

For people who developed blindness well into life, it's likely that they at least have the capacity for visual experience. Whether or not they actually experience visual blackness or no visual phenomena at all, and how this unfolds as a function of time spent in blindness, is really an empirical question that would be best answered by asking for the introspective report of a suitable person. Whatever the answer turns out to be, though, a significant part of the story should be the physiological state of the brain regions that normally support visual experience. It's not just a matter of simple cognitive comparisons.

 

[dimensionless]

It would depend on why they are blind.

I would think that blind people are unable to see blackness. My reasoning for this is that sighted people are not able to see blackness. They can only see light. If there is no light hitting your photo-receptors (retina?) then the eye will not send nerve impulses to the brain, so blackness is not something that can be seen.

Maybe this view is applicable to clams, jelly fish, plants, and rocks. I'm not really sure.

 

[Danger]

And what about animals without any eyes, do they see blackness aswell?
Do plants?

There are varying degrees of photosensitivity among animals. On different levels, you can actually trace the evolution of the mammalian eye. Some merely have mildly photosensitive patches of skin cells, more advanced types have crude retinae, others add a lens to the system, etc.. Insect compound eyes seem to be in a class by themselves, but I'm not sure.
Since plants aren't conscious, I doubt that you can apply the term 'see' to them. They're obviously photosensitive, though. Most tend to grow toward the sun, which is fairly logical for organisms that run on photosynthesis.

 

[PIT2]

For people who developed blindness well into life, it's likely that they at least have the capacity for visual experience. Whether or not they actually experience visual blackness or no visual phenomena at all, and how this unfolds as a function of time spent in blindness, is really an empirical question that would be best answered by asking for the introspective report of a suitable person. Whatever the answer turns out to be, though, a significant part of the story should be the physiological state of the brain regions that normally support visual experience. It's not just a matter of simple cognitive comparisons.

But is it (theoretically) possible for us, with our functioning visual cortex, to become visually aware of the blackness behind, below, above and besides our heads?

I imagine this would look like 360 degree (both left/right and up/down) vision with a small section (that what's in front of us) being illuminated.

 

[hypnagogue]

But is it (theoretically) possible for us, with our functioning visual cortex, to become visually aware of the blackness behind, below, above and besides our heads?

Well, there is no blackness behind our heads-- that was the point of my using that example. If you compare the visual experience of complete darkness to the visual experience of seeing out the back of your head, you should find that they are different, because the latter isn't a visual experience at all. You might think of it as analogous to the difference between the written numeral "0" as compared to the complete absence of any written number whatsoever. They may amount to roughly the same thing conceptually, but in one case there is a representational vehicle, a pointer which we interpret to mean "nothing," and in the other case there is literally nothing to begin with.

I don't know whether or not a normally structured visual cortex could support a visual experience as of complete blackness, as if it were located in the experiential space behind one's head. Certainly if we remove the "normally structured" constraint, I imagine it would be quite possible. Some people claim to be able to experience 360 degree vision in lucid dreams, so it may be possible even for more or less normally structured human brains in the proper circumstances.

 

[PIT2]

When our pupils get smaller/larger, or our eyes get tired, our field of vision can also change in size. However we do not experience the removed parts at the edges of our field of vision as blackness - we simply don't experience it, just like at the back of our heads. So i imagine there must be some kind of filter in the brain that selects which 'black patches' we are aware of and which ones we arent (black patches here being an absence of light hitting our retinas).

If i focus on the edges of my field of vision however, i can experience a little bit of blackness there. So it seems to me like this is just a matter of focussing hard enough.

 

[masudr]

I read somewhere (but cannot cite the reference for I cannot remember where I read it) that blind people see black and white dots.

I think it's safe to say that most of the posts on this thread (including mine) are speculation to some extent, and as someone says, until we ask someone who was born blind, but later acquired vision, we wouldn't know.

 

[octelcogopod]

I think the absence of anything on the back of our heads is only possible because we actually see at the front of our heads.

Kind of like you can't have black without white.

 

[Line]

Being that the brian processes visual information a person who had blindness in the eye or optic nerve shoudl see blackness. A person whom is blind do too a malfunctioned brain should see nothing.

 

[Mickey]

Do blind people see blackness?

(and before u say, "no theyre blind", please think about it!)

I've thought about it. Actually, I figured that one should come to the conclusion, "no, they're blind," after thinking about it, and not before.

People who are not thinking would try something that has nothing to do with being blind, like closing their eyelids. Closing your eyelids does not end your sensitivity to light and its absence, it only reduces the amount of light entering your eyes. When you reduce the light level, you are sensing the absence of light as blackness. Without sensitivity to light and its absence, you would not see blackness.

So, before you ask the question again, why don't you please think about it. :shy:

 

[eyobale]

we percieve our universe with our sense organs. an absense of a sense organ cuts and avoids the existence of that universe. you cannot percieve the concept vision, without a sense organ(call it optic nerve) or other stimulator. if you are told the situation of a person who do not have that sense, and you are not that type, then that will be only speculation and requires faith, you can not prove it. People who are not Blind can not tell the situation because they don't have the capability not to have vision.
Even, if you ask a blind person with no vision, it will misled you, because he is going to use the terms that we agree, it is a belief for him, he don't know about it, because he don't have the senses(only faith). for those who do not have the sense of vision, vision and darkness is an imagination or concept that doesn't exist in their universe, but are persuaded to believe that they exist. Faith is natural, the absense of a sense organ force you to believe in something. it is like believe in a spiritual body, because we do not have the sense organ to percieve them, we only accept and imagine.

 

[Dadface]

May I recommend an excellent book
Eye and brain by R L Gregory
I had this book years ago but I think a friend must have taken it on permanent loan.I seem to remember that the author addresses some of the issues being discussed here.

 

[Ian_Brooks]

I imagine it would depend why they are blind. I don't know much about the reasons for blindness but I imagine it can either be caused by the eyes or by the brain.

If the eyes themselves are damaged then it would be the same as you being in a very dark room, that is no photons are hitting your eyes so the eyes don't send any signals to the brain and you "see" darkness.

If it's part of the brain that's damaged then I guess they wouldn't see anything. It would be as if they don't have the sense of sight at all.

i would rather consider it as not seeing at all

its like the mind set we have when we close our eyes, not when we enter a dark room

Are we continuously 'seeing' when we close our eyes? How about when we enter a dark room?

 

[FrazerW]

Well eyes still interpret light regardless if the person is blind or not, what we classify as black is a lack of light so blind people would see 'blackness' but if for say we had no eyes we would not visually interpret light altogether; no 'black'.

 

[TVP45]

If a person is born profoundly blind, she will have little or no visual cortex development and, it can be argued, "sees" nothing at all. It should be noted that many blind people have some vision. All that aside, there is a simple experiment worth doing if you have an interest in this. Enter a mine or cave and move perhaps a half mile underground and turn out the lights. Save for the odd particle that zaps your retina, you will find that the sensation is quite different from seeing. If you're even more serious, add some electrodes about your eyes and record the eye movement signals.

 

[Mgt3]

Do blind people see blackness?

(and before u say, "no theyre blind", please think about it!)

I am qualified to answer this question because I am completely - and permanently - blind in one eye. At one time I was blind in both eyes. Yes, blind people see a blackness, although it's more of a greyish-black. It's difficult to describe unless you experience it yourself, which I hope you never do.

 

[Quantum77]

that's because you have another eye to compare it to, and this compares the light to the black space. blind people don't see black, you are not fully blind therefore you see black portions, whereas if you are completely blind you do not see black, but rather nothing at all. For example, the blind spot in your eye reveals it as a black spot no? but that's because it is comparing it to other colours around it, if you are fully blind you have no other colours to compare too and so therefore do not see black you only see black when you have other colours to compare it to and fully blind people have no other colours to compare it to, so therefore do not see black, but rather nothingness...

 

[OAQfirst]

I would say the best way to see the way the blind see is to look through the eyes on the back of your head.

And this thread is old.

 

[Quantum77]

yeah like you can't see the same way you can't see what's behind you, not because their is something blocking the light (eyelids, Earth blocking the sun = night)

 

[jwlm88]

It is difficult for a person who experiences visual stimulation to imagine being completely cut off from it. I personally feel as was stated earlier in the thread that what is perceived is based on the reason for blindness. My grandfather was legally blind (due to Macular degeneration), however could see out the corners of his eye. He described it himself to the family, while he was alive.

If the problem is the eye, the eye would not absorb light correctly making the persons vision be complete darkness or a degree of darkness based on the extent of the damage or impairment.

If the problem is in the brain, the person, in my opinion would most likely perceive not necessarily a darkness but an inability to interpret the visual stimulus.

 

[eyobale]

it is like do the dead feel the universe, the blind are dead for the light universe, the presense and absense of light, we sense our universe with our senses, and it doesn't require for your brain to die, if you don't have the sense organ, you are dead to that universe. it is like you can not sense heat if your sense for that dies. vision on the other hand is a vague word that can be used in different ways. if your definition for vision is the combination of light, color/object/ and eye(all components functioning), the absense of one will make you blind. it is like if one part of the computer component fails to work the whole system ceased.

 

[334dave]

this thread (at times) is thought provoking..
MHO - if one has never experienced some thing there is no way to relate
using sensors that create images on the back has shown that the blind can adapt to "sight" of some sort, "sight" being a remote sensing
also studys have shown that a blind person with medically corrected
( shall we say "restored" for lack of a better word )
"vision" do not have depth perception..
their vision is more on the order of how norman sigthted people
see a photographic image- flat without depth..
so a ball does not get closer ,,, it only gets larger..
i believe what the one guy mgt says, he lives with it..
but heck what do i know ...

 

[doriusrex]

I have an experience that might shed light on the issue.

Once I had a problem where I began to lose sight in my right eye while I was at home looking at my computer. When this happened, a black spot did not begin to grow where my vision was disappearing, rather-no input was received at all.

It looked as if words were disappearing from the page and it was replaced with nothing. No black, no white, not gray or anything really in between. There was simply a...lack.

I could almost feel it, the lack of seeing something there. It was as if something was obscuring my vision, but whatever was obscuring my vision was unseeable itself. It was similar to the effect that happens when you rub your eyes too hard and can't see anything for a few moments afterward. It's not blackness, but you just can't see. At least that's what happens for me.

 

[russ_watters]

That sounds lik macular degeneration - are you seeing a doctor for that?

People - even healthy ones - have a "blind spot" where objects in their field of view can't be seen due to the lack of sensors in that area of the retina. Yes, that means not seeing anything, not "seeing blackness".

 

[doriusrex]

I called 911 when it happened since I was losing vision and didn't want to risk driving to a hospital. By the time the paramedics got me to the proper hospital (the ambulance was turned away from the first one they tried since they didn't have an optometrist) the "nothing" had become neon glowing flames, which spread and gradually disappeared. The doctor didn't see anything inside my eyes (he ran a multitude of tests) and said that as far as he could tell I was fine. Just one of those things, he said. Hasn't happened since.

 

[334dave]

in the Jest the Last week I experienced a strange vision issue!
things suddenly seem brighter .. then suddenly my vision got
"nothingness " spots!
i could not see a yellow dog in front of a light tan/gray fence!
looking at my blue jeans i only saw blue lines weaving around brown spots..
sun glasses helped for jest a few moments
then i had to go inside as it hurt to "look"
not like were they dilate your eyes and it the light hurts your eyes..
i also had cramps in my arms and legs..

at the ER on Saturday ( yes yesterday) i got the bad news
that the visual effect with the start of cramps in my arms meant
i was suffering heat stroke !
that it happen 3 days in a row more then two times each day
made the doctor tell me i was lucky grand daddy to be alive still

the visual effects were generated in the cerebral cortex and were evidence of damage starting in the 'miniscua sheath" ( sp and may have wrong term)
covering of the nerves in the brain..
cramping of the arms and body evidence that damage in the motor cortex also was occurring

advice to anyone with some thing different happening in visual experience
get to a ER ASAP!

 

[junglebeast]

I wouldn't be surprised if blind people still have a sense of sight that is more of a mental map reconstructed from other sensory inputs. We know that blind people who have had tactile matrix devices attached to their stomach have reported being able to "see" using this device..we know that the brain dynamically rewires itself to not waste neurons...we know that people can learn to use echolocation...

 

[jbomb27]

It depends, I had an eye opening experience last year when I discovered that I was legally blind in my left eye, my right eye had been doing all the work. Being blind in one eye due to partial retina detachment I can still see a little bit out of that eye when I focus on try to use it the image is blurry like it would be if you were looking through like three feet of clear moving water, colourful but rough and no depth perception, in the dark only light stuff is 'visible'(blurred) out of that eye; everything else is black.