Visual reality: a new insight.

[Dymanic]

Originally posted by Interesting Ian

If one has been blind throughout their lives due to some defect in their eyes, then this is cured, and then they have perfect vision (although they can't see very well) then clearly thier brain is "wired to process visual information in the first place".

No, it ISN'T.

It's not the brain, it's rather a psychological thing. They haven't had any opportuinity to build up a model/theory about the world to make sense of it.

...NO NO NO. You just don't understand. It is ABSOLUTELY a "thought thing".

NO, NO, NO! You are quite spectacularly wrong about this, Ian. It is absolutely a difference at the level of structure in the brain. It is very much the same as with language aquisition. Infants have tremendous neural plasticity in the structures designed to recieve a particular type of input, but at some point, the plasticity is 'all used up'. The flexibility is a one-time special offer (which is why adults learn second languages so much more slowly than infants do their first language). If deprived of input, those structures will not develop fully. The structure of the brain of a person blind from birth is different from that of a sighted person.

 

[epepke]

I can see that the eye/brain could fathom that some objects were closer than others, and some further than others. But how does it get an accurate picture of events? None of the replies here have answered that question.

It doesn't generate an accurate picture! Have you never heard of optical illusions? Have you never been exposed to the fact that generations of people thought that all the stars were at the same distance?

 

[Interesting Ian]

Ian
If one has been blind throughout their lives due to some defect in their eyes, then this is cured, and then they have perfect vision (although they can't see very well) then clearly thier brain is "wired to process visual information in the first place".

Dymanic
No, it ISN'T.


Ian
It's not the brain, it's rather a psychological thing. They haven't had any opportuinity to build up a model/theory about the world to make sense of it.

...NO NO NO. You just don't understand. It is ABSOLUTELY a "thought thing".

Dymanic
NO, NO, NO! You are quite spectacularly wrong about this, Ian. It is absolutely a difference at the level of structure in the brain. It is very much the same as with language aquisition. Infants have tremendous neural plasticity in the structures designed to recieve a particular type of input, but at some point, the plasticity is 'all used up'. The flexibility is a one-time special offer (which is why adults learn second languages so much more slowly than infants do their first language). If deprived of input, those structures will not develop fully. The structure of the brain of a person blind from birth is different from that of a sighted person.

They have the visual information coming in. They have perfect vision. Therefore it's a mental thing. They haven't developed an appropriate low level theory about the world. I'm not of course denying there is neural correlates associated with this development of a low level theory and that the lack of such plasticity within the brain makes the acquisition of seeing that more difficult. But you're saying that a person, blind from birth, then being made to have vision for the very first time, could therefore never be made to see without some operation on the brain. Or maybe even never be able to see at all. I find this extremely implausible.

 

[Upchurch]

Re: Re: Re: Re: Re: Re: Re: Visual reality: a new insight.

Lifegazer explained in his opening post. We learn to see at a distance by perceptual cues like Russdill mentioned. The point being is that when we see something at a certain distance, this is a learned ability rather than an innate one.

Yes, we have to learn to use our eyes. How does that imply that (1) we do not literally see at a distance and (2) there is no external reality?

It seems to me that what you're saying is analogous to saying that because we have to learn to drive a car, we can not literally drive a car from point A to point B. Because we have to learn how to use our own eyes means that we cannot litterally see objects at a distance? Are we metaphorically or symbolically seeing objects at a distance? I still don't understand what you're trying to get at.

 

[Upchurch]

It seems to me that the argument you were making is that we are not a priori cognisant of distance from our visual sensations alone. Seeing is therefore a learnt ability, ultimately derived from the correlations between what we see and our sense of touch. Using visual sensations alone, visual cues thereafter give us the idea of how far away an object is.

Are you sure about this or are you guessing? Have there been any studies or experiments about how we begin to corolate our visual inputs with distance? It's true that infants' sense of touch develops before their sense of sight, but its also a much simpler mechanism and, in early life, is much more essential to survival than sight is. I'm not aware of anything that says that touch is essential to learning how sight works.

Hence one cannot justify the existence of a material world or "external reality" by saying one is immediately acquainted with such a reality.

I'm not convinced by your argument that we don't litterally see objects therefore, I don't buy your conclusion, but I'm still not sure I understand the premise.

On the other hand, only a philosophically naive person would maintain this, and if such a person were so disposed, they are unlikely to understand the argument that we do not literally see at a distance either!

Is it naive to admit what one does not understand or is it just honest? Regardless, it is fortunate that my sense of self-esteem is not dependant on Ian's rather biased analysis.

 

[Dancing David]

Ian:

Glad to have you back!

But NO, NO NO is the rant of a toddler and not worty of you.

When you say 'perfect vision': there is a hole in your definition:
I will digress briefly but I think we can add clarity.
The precess of perception
1. Reaction of the sense organ to some thing that creates the sensation.
2. Transfer of that information to the processing area of the brain.
3. Processing of the material into coherent form and presentation/interaction with the frontal cortex.

In step two there is a learning process that most infants and children go through, in that the brain has to learn to sort the information presented by the sense organ into a 'meaningful' or 'coherent' perception. So a baby need to have interaction with the various colors and shapes to be able to percieve them later. Which is where YHVH was headed in talking about tortured kitties.

This process would be lacking in the person who was blind from birth, so from the materialist POV, they are not going to have pefect sight even if you give them perfect vision, because thier brain has not learned to interpret the data presented by the sense organ of the yes.

1. When you say 'perfect vision', most materialist would assume that you mean, that the sense organs were functioning and that they could transmit a clear signal to the visual cortex.

2. When you say 'perfect vision', I think that what you are trying to say is , something like, 'they have been granted the ability to see which in this case would include : the sense organs, and whatever visula 'wet-ware' that a normal brain would have to be able to process the information in the visual cortex'. Am I right, because from the materialist POV, this is important, because that 'wet-ware' is a learned maturation process, no exposure no process.

3. Which gets to the higher level of perception, it would seem that you are saying that if a person who was blind recieved the ability to see , and for thier visual cortex to be able to make a coherent 'perception' of the visual data, then they would be unable to recognise a 'sphere' or a 'cube' if it was presented to them for the first time.

That seems like a no brainer Ian, and one that a materialist would agree to, language is labeling and the lables that they have would not have had the cross reference yet.

So if theyw were presented with a dog, they might recognise that it was a 'dog' because they can smell 'a dog smell' but they are not going to regocnise it a dog from purely visual cues alone.

I am not sure that they need a theory to recognise the cube, I think that a 'person of low cognitive functioning' could learn to recognise the cuce, by exposure.

I think I understand where you are going, but I would say that most learning and labeling occurs through exposure and not the higher cognitive functions.
Have you ever taught a child to tie thier shoes?

 

[Interesting Ian]

Re: Re: Re: Re: Re: Re: Re: Re: Visual reality: a new insight.

Originally posted by Interesting Ian

Lifegazer explained in his opening post. We learn to see at a distance by perceptual cues like Russdill mentioned. The point being is that when we see something at a certain distance, this is a learned ability rather than an innate one.

Yes, we have to learn to use our eyes. How does that imply that (1) we do not literally see at a distance and (2) there is no external reality?

It seems to me that what you're saying is analogous to saying that because we have to learn to drive a car, we can not literally drive a car from point A to point B. Because we have to learn how to use our own eyes means that we cannot litterally see objects at a distance? Are we metaphorically or symbolically seeing objects at a distance? I still don't understand what you're trying to get at.

Well, your analogy is hopelessly off.

Yesterday I provided a particular argument for what distance is. I said normally all distance means is that if I make certain bodily movements (eg walk towards object in question), I will receive a certain tactile sensation. Most crucially though distance doesn't mean anything more than this.

Now obviously, from the visual sensation of an object alone, we can learn approximately how much walking needs to be done before we are able to touch the said object. But the crucially important thing here is that this is all that it means to say that an object resides at a distance from you. It does not literally reside at a distance from you if this means anything more than certain bodily motions are required before having a tactile sensation of the seen object.

Thus a person who argues that we directly see a material world, or "external world" is simply at error. All we have are certain qualia, and experiences of the movements of our bodies. Visual and tactile sensations are strictly speaking heterogenous i.e there is no innate relationship between, say, a seen apple, and the sense of touch of an apple on reaching out our hands. Rather we have families of qualia, meaning that certain qualia, a particular visual sensation, and tactile sensation etc, are regularly found together. Thus, for example, we might have the visual appearance of an apple, what it feels like, what it tastes like, and we group together these qualia and refer to this family of qualia as an apple.

 

[Upchurch]

Re: Re: Re: Re: Re: Re: Re: Re: Re: Visual reality: a new insight.

Yesterday I provided a particular argument for what distance is. I said normally all distance means is that if I make certain bodily movements (eg walk towards object in question), I will receive a certain tactile sensation. Most crucially though distance doesn't mean anything more than this.

I disagree, but you are taking your usual immaterialist assumption and I am not. So, once again, it comes down to our assumptions, doesn't it.

But the crucially important thing here is that this is all that it means to say that an object resides at a distance from you. It does not literally reside at a distance from you if this means anything more than certain bodily motions are required before having a tactile sensation of the seen object.

In other words, it doesn't exist independantly of the observer? Again, assumptions, assumptions, assumptions....

Thus a person who argues that we directly see a material world, or "external world" is simply at error. {blah, blah, blah}

I thought you actually had some point, but you just feel back into your old rhetoric. Nevermind.

edited to add: oh, and if you were just going to assume an immaterialist position anyway, what did it matter if the sense of sight was learned or not. If our understanding of distance was innate to humanity, wouldn't that be more condusive to believing that the "external world" is merely a constuct of the mind? Doesn't the fact that we have to learn what distance is from the external world suggest that it is a property of the external world and not ourselves?

 

[Paul C. Anagnostopoulos]

Ian! IAN! For Ed's sake, man. If you're just going to assume an immaterialist position and then try to shoehorn all our neuropsychological knowledge into it, you first need to come up with a coherent model for your immaterial world. Otherwise you're just flailing around.

Here, read this and then work it all out:

Gary Marcus, The Birth of the Mind: How a Tiny Number of Genes Creates the Complexities of Human Thought, Basic Books, 2004.

Also, of course, The Man Who Mistook His Wife for a Hat.

~~ Paul

 

[Paul C. Anagnostopoulos]

Ian said:
Yesterday I provided a particular argument for what distance is. I said normally all distance means is that if I make certain bodily movements (eg walk towards object in question), I will receive a certain tactile sensation. Most crucially though distance doesn't mean anything more than this.

Or throw a ball and time how long it takes to get there. Or launch a rocket after calculating how long it will take, then find out you were right. Or watch an object (with which you don't interact) move between two points at a known speed. Or a thousand other ways of determining distance. (Notice that your "bodily movements" are also based on an internal sense, so you have one sense producing another.)

Given that, we have two possibilities:

• There is an external world that obeys certain physical laws.
• There is only an internal world, but it obeys laws that are just as exquisitely predictable as those physical laws.

Yet, somehow, you think that the first possibility is foolish, while the second is reasonable. And also, somehow, you think the second possibility affords you free will.

They are equivalent.

~~ Paul

 

[Interesting Ian]

This is hopeless!

I am not giving an argument for immaterialism! I thought we all agreed that we only learn about distance ultimately from the correlations beteen particular visual sensations and tactile sensations?? Are you all now disputing this??

I'm simply saying we cannot justify the existence of a material world by claiming that we directly are aware of objects residing outward of us. I thought people basically agreed with me. But now people seem to think I have some sort of cunning plan to logically show idealism/immaterialism must be true!

Look, there is one very important thing that people MUST try to understand.

The issues I am talking about are epistemological not ontological!

I am not saying that there absolutely cannot be objects lying literally at a distance away from us; just that we cannot infer it. Our understanding of distance is derived from the patterns of primarily our visual and tactile sensations. To say that objects literally reside at a distance outward from us, is to go beyond what we can possibly infer ie it goes beyond epistemology and becomes an ontological issue.

Likewise, I am not saying there are no apples, understood as a reality amounting to more than the sum of a family of qualia. There might be, but this is an ontological issue rather than an epistemological one. Indeed I myself believe in the existence of such apples, even if they are not material. I might, for eg, think of apples as conceptions in the infinite mind which our theories about apples (i.e our idea about apples derived from particular qualia), are reflections of.

But all this is getting a bit complex. None of you even understand the simple stuff!

 

[Interesting Ian]

Or throw a ball and time how long it takes to get there. Or launch a rocket after calculating how long it will take, then find out you were right. Or watch an object (with which you don't interact) move between two points at a known speed. Or a thousand other ways of determining distance.

That's all fine. They all amount to particular visual sensations though. What is it all supposed to show? It certainly doesn't show that distance is anything more than particular patterns represented by our qualia.

(Notice that your "bodily movements" are also based on an internal sense, so you have one sense producing another.)

One sense doesn't produce another! Our senses are heterogenous!

 

[Upchurch]

Re: This is hopeless!

I am not giving an argument for immaterialism! I thought we all agreed that we only learn about distance ultimately from the correlations beteen particular visual sensations and tactile sensations?? Are you all now disputing this??

No one is arguing about how we learn to use our senses, Ian. We're arguing about gaps in logic you've used to reach your conclusions.

I'm simply saying we cannot justify the existence of a material world by claiming that we directly are aware of objects residing outward of us.

Now you're using different language. I don't think any of our senses can be divided into "direct" or "indirect" classifications. And, anyway, that isn't what you said. You said that we do not literally see objects at a distance because objects don't have a distance independant of the observer. This is an immaterialist assumption and one I don't agree with.

I thought people basically agreed with me. But now people seem to think I have some sort of cunning plan to logically show idealism/immaterialism must be true!

Then explain how you can conclude that a distance between two objects has no meaning unless there is an abserver present, without resorting to immaterialism.

I am not saying that there absolutely cannot be objects lying literally at a distance away from us; just that we cannot infer it.

But, by saying that distance has no more significance than its relation to an observer, you are infering that there absolutely cannot be objects lying literally at a distance. Otherwise you would have said something to the effect that "distance might not mean anything more than this" rather than "distance doesn't mean anything more than this."

Do you understand the difference?

Our understanding of distance is derived from the patterns of primarily our visual and tactile sensations. To say that objects literally reside at a distance outward from us, is to go beyond what we can possibly infer ie it goes beyond epistemology and becomes an ontological issue.

That's fine, but it isn't what you said. I can only read what you say, not what you think.

 

[Upchurch]

One sense doesn't produce another! Our senses are heterogenous!

Tell that to lifegazer.

 

[Dymanic]

Originally posted by Interesting Ian

They have the visual information coming in. They have perfect vision. Therefore it's a mental thing

Let's call the visual information the 'signal' end of the system, and the brain the 'reciever' end. (This is a bit of an oversimplification, as human eyes are essentially extensions of the brain). What you are saying is that the signal alone constitutes perfect vision, regardless of the ability of the reciever to properly interpret it.

But you're saying that a person, blind from birth, then being made to have vision for the very first time, could therefore never be made to see without some operation on the brain. Or maybe even never be able to see at all.

I'm saying that the degree to which such a person could develop the ability to process visual information would depend a lot on the age at which sight was restored. In addition to the problem with decreasing plasticity, there is evidence that what is called 'complex form processing' continues to develop well into adulthood -- so a person who got a late start would likely never catch up.

Study on newly sighted blind people

Normal visual experience necessary for proper brain development

 

[Paul C. Anagnostopoulos]

Ian said:
I am not giving an argument for immaterialism! I thought we all agreed that we only learn about distance ultimately from the correlations beteen particular visual sensations and tactile sensations?? Are you all now disputing this??

Indeed, everything we know we learn about through our senses. It is possible that the things we sense are external to us. It is also possible that our senses are really "virtual senses" being fed inputs from some uber-being.

As you say, what we can learn through our senses is an epistemological question. Whether there is an external world or virtual senses is an ontological one. However, the severe constraints placed on the situation by the epistemological reality we all agree on renders the ontological question moot, I think. The two ontological positions are equivalent.

~~ Paul

 

[Interesting Ian]

Let's call the visual information the 'signal' end of the system, and the brain the 'reciever' end. (This is a bit of an oversimplification, as human eyes are essentially extensions of the brain). What you are saying is that the signal alone constitutes perfect vision, regardless of the ability of the reciever to properly interpret it.

I'm saying that the degree to which such a person could develop the ability to process visual information would depend a lot on the age at which sight was restored. In addition to the problem with decreasing plasticity, there is evidence that what is called 'complex form processing' continues to develop well into adulthood -- so a person who got a late start would likely never catch up.

Study on newly sighted blind people

Normal visual experience necessary for proper brain development

None of this is relevant. I'm not arguing against materialism. To have perfect vision we need a brain, but to have perfect sight involves understanding the world in a certain way (when I refer to "seeing" I mean interpretation of a visual perception. The terminology used in the article you linked to differs from mine). And yes this might be compared to acquiring a language, and it might well be more difficult later in life than as a baby due to the "plasticity" of the brain. OK that's fine. What are you disputing? Are you somehow trying to argue that this vindicates materialism?

The article states:

"Fine, MacLeod and their co-authors suggest that some visual mechanisms such as motion processing are more hard-wired than others"

This is just simply not relevant! A person obtaining vision for the first time ever can see motion because motion involves no theory! 3D objects do! It is very VERY obvious why such a person can detect motion and not 3D objects. It's a psychological thing. Yeah there are neural correlates to this mental activity. So what??

PS Could I please request that rather than you simply posting links, you quote what you believe to be the relevant stuff?? I really can't be bothered to read through a whole web page, especially as invariably they never have anything relevant to say.

 

[Paul C. Anagnostopoulos]

Ian said:
This is just simply not relevant! A person obtaining vision for the first time ever can see motion because motion involves no theory! 3D objects do! It is very VERY obvious why such a person can detect motion and not 3D objects. It's a psychological thing. Yeah there are neural correlates to this mental activity. So what??

You're talking out of your arse, inventing ad hoc it-is-very-obviousnesses as you need them.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=33196

The fundamental problem in motion perception is the inevitable ambiguity of any sequence of images projected from a source onto a plane, such as the central retina: the observer must respond appropriately to the stimulus, but the sequence of retinal images does not allow a definite determination of its source. There is no analytical way to resolve this dilemma, because the requisite information is not present in the sequence of retinal images. This problem could be solved, however, if the perceived motion were determined by accumulated experience, such that the percept elicited would always be isomorphic with the probability distribution of the source of the stimulus. In this conception of motion perception (and vision more generally), the neuronal activity elicited by any particular stimulus would, over the course of both phylogeny and ontogeny, come to match ever more closely the probability distribution of the same or similar stimulus sequences (12). The aim of the experiments reported here was to test this hypothesis by establishing the probability distributions of the physical displacements underlying simple linear motion stimuli and then comparing the percepts predicted on this basis to the percepts reported by subjects.

~~ Paul

 

[Interesting Ian]

Ian said:
This is just simply not relevant! A person obtaining vision for the first time ever can see motion because motion involves no theory! 3D objects do! It is very VERY obvious why such a person can detect motion and not 3D objects. It's a psychological thing. Yeah there are neural correlates to this mental activity. So what??

Anag
You're talking out of your arse, inventing ad hoc it-is-very-obviousnesses as you need them.

Oh for Chr*st's sake. If we had all lived 10,000 years ago, and therefore we all knew nothing about the brain whatsoever, I could have told you that a person who acquires vision for the first time ever would be able to see motion but not 3D objects.

It's a philosophical question, not a scientific one.

Understand yet??

I'm not prepared to argue about this anymore. I have informed people what is the case.

Goodbye.

 

[Paul C. Anagnostopoulos]

And, you know, what in holy hell is the point of the uber-being projecting virtual images of a virtual 3D world onto our 2D retina? Why not just give us an accurate mental picture of this virtual world? If there is an uber-being, he's obviously an amateur or a joker.

Sorry, I had a bit of an ontological moment there.

~~ Paul