Recovery from blindness

Recovery from blindness is the phenomenon of a blind person gaining the ability to see, usually as a result of medical treatment. As a thought experiment, the phenomenon is usually referred to as Molyneux's problem. The first published human case was reported in 1728 by the surgeon William Cheselden. Patients who experience dramatic recovery from blindness experience significant to total agnosia, having serious confusion with their visual perception.Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal, and nighly of the same bigness, so as to tell, when he felt one and the other, which is the cube, which is the sphere. Suppose then the cube and the sphere placed on a table, and the blind man made to see: query, Whether by his sight, before he touched them, he could now distinguish and tell which is the globe, which the cube? To which the acute and judicious proposer answers: 'Not. For though he has obtained the experience of how a globe, and how a cube, affects his touch; yet he has not yet attained the experience, that what affects his touch so or so, must affect his sight so or so...'the objects to which he had hitherto used to apply the terms up and down, high and low, were such as only affected or were in some way perceived by touch; but the proper objects of vision make a new set of ideas, perfectly distinct and different from the former, and which can in no sort make themselves perceived by touch (sect. 95).When he first saw, he was so far from making any judgment of distances, that he thought all object whatever touched his eyes (as he expressed it) as what he felt did his skin, and thought no object so agreeable as those which were smooth and regular, though he could form no judgment of their shape, or guess what it was in any object that was pleasing to him: he knew not the shape of anything, nor any one thing from another, however different in shape or magnitude; but upon being told what things were, whose form he knew before from feeling, he would carefully observe, that he might know them again; Recovery from blindness is the phenomenon of a blind person gaining the ability to see, usually as a result of medical treatment. As a thought experiment, the phenomenon is usually referred to as Molyneux's problem. The first published human case was reported in 1728 by the surgeon William Cheselden. Patients who experience dramatic recovery from blindness experience significant to total agnosia, having serious confusion with their visual perception. The phenomenon has often been presented in empiricism as a thought experiment, in order to describe the knowledge gained from senses, andquestion the correlation between different senses. John Locke, an 18th-century philosopher, speculated that if a blind person developed vision, he would not at first connect his idea of a shape with the sight of a shape. That is, if asked which was the cube and which was the sphere, he would not be able to do so, or even guess. The question was originally posed to him by philosopher William Molyneux, whose wife was blind: In 1709, in A New Theory of Vision, George Berkeley also concluded that there was no necessary connection between a tactile world and a sight world—that a connection between them could be established only on the basis of experience.He speculated: This thought experiment (it was a thought experiment at the time) outlines the debate between rationalism and empiricism; to what degree our knowledge of the world comes from reason or experience. There are many stories or anecdotes of the phenomenon, preceding the first documented case, including one from the year 1020, of a man of thirty operated upon in Arabia. Before the first known human cases, some tests were done rearing animals in darkness, to deny them vision for months or years, then discover what they see when given light. A. H. Reisen found severe behavioural losses in such experiments; but they might have been due to degeneration of the retina. The first known case of published recovery from blindness is in 1728, of a blind 13-year-old boy by William Cheselden. Cheselden presented the celebrated case of the boy of thirteen who gained his sight after removal of the lenses rendered opaque by cataract from birth.Despite his youth, the boy encountered profound difficulties with the simplest visual perceptions.Described by Cheselden: