A Thought Experiment

Suppose that you were blind from birth, and by some absolute miracle you can suddenly see. In front of you there is a spere and a cube. You have previously known both of these objects only to touch. Do you think that now, with this new found gift of sight, you would be able to discern which is which by means of your sight alone, without touching either object?

[Mayhap]

Yes, because you have already seen these in your imagination.

But can somebody who has never seen imagine what it is like to see? I doubt it. A blind person's thoughts and imagination would, I believe, be dependant on instantiations of the other senses they have actually already experienced. How could they know what something looks like if they don't even know what it is like to see?

Yes. Corners.

[benkahuna]

Certainly. Spacial understanding doesn't occur only by sight. Once you could see well enough to understand space, you'd understand the object.

From what I understand about neurobiology, you'd need time to get consistent correspondence between visual input and reality. During neurobiological development the wiring of the nervous system occurs based on trial and error and the correspondence of input with material reality. This dynamic process still occurs in adults and can be shown by wearing glasses that invert images (takes about 1 week or something to adjust and images flip so you see normally and have proper depth perception, balance, etc.), taking the glasses off (reverse process, same time period), or by taping a finger to the palm for only an hour or so. There's a constant remapping based on sensory input which is similar to neuronal migration, synapse strengthening, and other major structural changes of the brain as it becomes shaped and organized in a consistent and accurate response to the environment.

Once you get this sort of consistent and meaningful correspondence of visual input to reality, you'd understand. Initially, you might not see properly at all. This plasticity as its called (learning and associated changes within the nervous system) occurs much more easily in the young and undeveloped and is much harder to achieve as you get older.

Without constant input (say you remove the primary visual cortex in an animal which is the initial target of the optic nerve and all visual input related to conscious appreciation of visual stimuli), entire circuits in the nervous system die. So, the ability to give a blind person sight as an adult or even after a few years of blindness would be absolutely extraordinary, probably resulting in multiple Nobel prizes.

There are three other pathways from the eye to other brain areas that do not involve conscious appreciation of light. Some are involved in eye movement and pupilar reflexes, others in hormonal output related to light intensity and diurnal cycles.

If you're confused, you might try reading a bit about the development of the nervous system. I recommend the chapters in Kandel's Principles of Neural Science.

[benkahuna]

Interestingly, you're pretty much on the ball here. It's even worse than you think. When someone goes blind, they gradually lose the ability to conceptualize sight as the neurons involved in conscious appreciation of site die. If you're intially blind, you have no concept of sight. You can imagine something, but not necessarily what it's like. The seeing and the concept of sight are pretty much a package, so far as cognitive studies have shown.

In order to see, you need fully functioning pathways in the brain, from the photoreceptor cells, to bipolar cells, to retinoganglion cells, to the primary visual cortex, to secondary visual processing areas specialized in either color and form or motion and orientation, etc.

Very interesting response Bekahuna, but I'm not so interested in the biological side of things, more the philosophical implications. I understand that in reality the thought experiment is extremely unlikely, and if such a thing did occur, the subject's gaining sight would be a gradual process and not immediate as in the thought experiment.

What I am interested in really however, and what I would have asked to a crowd better versed in philosophical jargon, is whether or not our modes of thinking (how we think, for example is it internal images, words, sounds etc)are innate or learned through experience.

How somebody answers the question I posed at the beginning of this post should have a direct correlation with the answer they would give to this broader more fundamental question. I thought I might get a few interesting responses from people with no education in this kind of stuff; sometimes you can learn more from a layman than from other philosophy students and lecturers who tend to talk a lot of crap to put it plainly!

[benkahuna]

Here's the problem. Much of the biology is known, so the answer no longer is philosophical. Philosophy and thought experiments are used in areas where science is currently incapable of treading. It's like asking if something heavier than air is capable of flight. If you live in a developed urban area, the constant proof makes the answer obvious, not philosophical.

The question you're asking has been answered to a large extent by cognitive scientists. The understanding of an object is not done through a single sensory modality (sight, sound, the many varieties of touch, olfaction, gustation). Connections between different brain regions specialized in a particular sensory modality suggest extrapolation of understanding of an object can occur from one sensory modality to another. There are a few levels at which this understanding may exist in the brain.

Here's a little experiment you could do without having a blind person. Have someone close their eyes and put two different unfamiliar objects in their hands, something novel. When they open their eyes, are they capable of correctly identifying which object was which? For a difference in form as rudimentary and unambiguous as that between a circle and a square, I'd say definitely.

It sounds like the question you're asking is what ways can we conceptualize an object. The answer is that we can conceptualize it via any sensory modality. Can the concept in one sensory modality of an object allow us to recognize it in sensory modality in which we have previously not experienced the object? Absolutely. Even a language description of an object can allow us to identify it correctly for the first time.

I can't imagine a real world object that didn't have some basis of understanding in a sensory modality of some sort. And I think this attachment to a sensory modality makes understanding concepts about other physical phenomenon (such as electromagnetic radation) so foreign and, at times, tricky to understand. It's simply outside our typical, material world experience. Maybe this idea is more something that you're looking for? Hope so.

The construction and existence of meaning and understanding is perhaps the most profound aspect of human consciousness. At the same time, meaning and understanding are the simplest foundations for everything else we do. Much like there is a semantic basis for language separate from the words themselves, I think there is a common, deeper understanding of an object, an anchor of sorts, upon which other concepts piggyback. Or you could just say the object concept is the intersection point for discrete ideas about the object. Considering the free-flowing, real-time, dynamic categorizing abilities of the brain, I'm not sure it matters whether there's a single concept or an intersection of discrete ideas or whether there really is a difference between the two possibilities. There's nothing that says our thinking should be so static or comprehensibly structured. Such structure might even be a hindrance to what our brains need to do for us in an evolutionary sense.

If you check the cognitive research out there, in many cases studies have been done that either attempted to, or successfully figured out this very idea to your satisfaction.

I'm sorry if I'm bursting the bubble on what you thought was a mystery of sorts and a real philosophical question, but my studies suggest that the answer to your original question (but not what you might really want to know about) is known.

Say you're blind I tell you to put both arms at 90 deg. angle and position them for ya......now you know what a corner is. I tell you a square has four corners where a sphere doesn't have a perfect corner...

Can you tell which is which?

[xniNja]

I'm nearly positive I watched a 70's video series in High School where similar experiments were actually done. As I remember, the significant note was that the blind people could tell the difference between perceived standards, once they had defined them.

In other words, once they were told that potatos were round, lumpy, and warm.. they would be able to distinguish them from bananas, being long cylindrical and cold.

Relevance? I don't know.

[Siegmund]

As long as you are receiving SOME kind of input to your brain, telling a sphere from a non-sphere is extremely easy: if it looks different when viewed (or touched, or anything-elsed) from different angles, it is a non-sphere.

If you asked someone to tell a cube from a pyramid, they might be fooled since they'd have to pay attention to what side they were looking at and how sharp the points were. Asked them to tell a regular octahedron from two square pyramids of a different b/h ratio glued base to base, or even an octahedron from a cube standing on its point, and you might well challenge them.

Incidentally, as far as identifying symmetry elements of somewhat obscure shapes goes - sighted people find this task much easier if they can handle a model, and easier still if they can mark the outside of the model with chalk, than if they have to do it by sight alone. (Abstract algebra teachers take note! I learned more about space groups from my mineralogy course in the geology department than I did in the math department! We actually had such models... a set of wooden blocks, between 50 and 100 of them, for all the common crystal shapes. I borrowed them as props for a seminar in the math department once and had a very warm reception.)