Do the Blind See?

Are the visual parts of the brain brought into play when a blind person feels their way around the world?

Folksonomies: philosophy experience sensation

Molyneux's problem

I shall here insert a problem of that very ingenious and studious promoter of real knowledge, the learned and worthy Mr. Molyneux, which he was pleased to send me in a letter some months since; and it is this:- "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 the sphere. Suppose then the cube and sphere placed on a table, and the blind man be made to see: quaere, 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, how a cube affects his touch, yet he has not yet obtained the experience, that what affects his touch so or so, must affect his sight so or so; or that a protuberant angle in the cube, that pressed his hand unequally, shall appear to his eye as it does in the cube."- I agree with this thinking gentleman, whom I am proud to call my friend, in his answer to this problem; and am of opinion that the blind man, at first sight, would not be able with certainty to say which was the globe, which the cube, whilst he only saw them; though he could unerringly name them by his touch, and certainly distinguish them by the difference of their figures felt. This I have set down, and leave with my reader, as an occasion for him to consider how much he may be beholden to experience, improvement, and acquired notions, where he thinks he had not the least use of, or help from them. And the rather, because this observing gentleman further adds, that "having, upon the occasion of my book, proposed this to divers very ingenious men, he hardly ever met with one that at first gave the answer to it which he thinks true, till by hearing his reasons they were convinced.


A blind person, familiar with a cube and sphere by touch, is made to see. Without touching the objects, would they be able to distinguish them by sight?

Folksonomies: empiricism senses experience thought experiment


Sensations are Related in the Brain

Production of speech is seen as a pure motor act, involving muscles and the neurons controlling them, while perception of speech is seen as purely sensory, involving the ear and the auditory pathway. This parcellation of the systems appear intuitive and clear, but recent studies [beginning with Taine 1870!] ... suggest that such divisions may be fundamentally wrong. Rather than separate processes for motor outputs and individual sensory modalities, adaptive action seems to use all the available context-specific information. That is, neural representations across the brain may be centered on specific actions. This view on neural representations puts 'Molyneux's Problem' in a new light. Unisensory signals are fused into multisensory motor representations unified by an action, but since Molyneux does not suggest any action, his 'problem' may be better viewed as an ill-posed question -- at least from a neuroscientific perspective".


Speaking involves not just motor functions in the brain, but auditory, suggesting sensory inputs for the brain are not segregated.

Folksonomies: neurology sensation