> if a man born blind can feel the differences between shapes such as spheres and cubes, could he, if given the ability to see, distinguish those objects by sight alone, in reference to the tactile schemata he already possessed?
If a sighted person can see an object and distinguish it by touch alone, the opposite must be true.
I teach whitewater kayaking, and part of what I teach is the kayaking roll, which involves being underwater with your eyes closed and executing a series of body and paddle movements. No matter how many times someone has seen a video demonstration of the technique underwater, they still are completely spatially disoriented the first few times they try the move. That's because it's completely new to them, and they've never actually had to map the series of physical sensations they experience onto movement without visual cues. I would bet the same is true of blind people: we recognize squares or circles because being born sighted, we have mapped our visual perception onto touch and onto language from an extremely early age. If you never went through that, there's no way you could recognize a square or a circle, because visual information doesn't fit anywhere into your understanding of how you observe space. We don't give kids physical toys just for their entertainment, they're also for building the link between visual, tactile, and language awareness.
I agree, I find the entire question to be difficult to define. If you magically bestowed sight upon a blind person with a sphere and a cube in front of them, they wouldn't even recognize them as separate objects. They would be bedazzled by a wave of sensory input they could make no sense of. Then over time, they would start mapping it to their understanding of the world and at some point they would be able to recognize the objects. When and how exactly that happens is interesting, but not really a deep philosophical question in my estimation.
>No matter how many times someone has seen a video demonstration of the technique underwater, they still are completely spatially disoriented the first few times they try the move.
How well does practice "on land" or "in the air" map to the same movement under water, with water resistance?
Not especially well. It's kind of helpful to understand conceptually what's going on, but ultimately the physical sense on land is completely different, and the student will still think almost entirely in visual terms unless they're already accustomed to taking coaching and have uncommonly good body awareness. Most of the time it's faster to just start the student off underwater and begin the process of learning that mapping between movement and touch without the visual part.
It turns out that this is true for sighted people only because sighted people have grown up both touching and seeing objects. Someone who was born blind has not yet learnt the skill of comparing the two sensations. (The experiment which demonstrates this is explained in the Wikipedia article.)
Did nobody read the article? There was an experiment done in 2003 that showed that no, newly-sighted individuals cannot distinguish objects based on existing tactile knowledge.
There is a TON of detailed and interesting information in the article I linked to. It is substantive, in contrast to the yes/no study described on the Wiki page.
Yet you felt the need to create a throwaway account in order to complain about any and all discussion in the comments which doesn't hinge on the original link...
If a sighted person can see an object and distinguish it by touch alone, the opposite must be true.