Molyneux's question : vision, touch, and the philosophy of perception / Michael J. Morgan.

  • Morgan, Michael J.
Date:
1977
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Molyneux's question : vision, touch, and the philosophy of perception / Michael J. Morgan. Source: Wellcome Collection.

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    DIDEROT'S 'LETTER ON THE BLIND' never seen it, is not always to the advantage of the latter. Do you think, Madame, that if you were shown a certain piece of trimming for the first time, you could deduce that it belonged to a hat? And if it is the more difficult for a blind person seeing for the first time to distinguish objects under their diverse appegirances, what would prevent him from taking the motionless figure in front of him in the armchair for a piece of furniture, or for a machine; and a tree with its branches and leaves moving in the wind for a sentient living thing? Madame, how many things are suggested to us through our senses; and what difficulty we would have, if it were not for our eyes, in attributing thought and sensation to a block of marble!^® It has thus been demonstrated that Saunderson's judgement in the instance of the circle and square would have been justified; and that there are cases where the reasoning and experience of other people can clarify the relations between sight and touch, and inform us that what is true for the one is true for the other. However, this would not make it any less necessary to exclude the senses when demonstrating what is called an 'eternal truth'. For if someone tried to prove to you that the projection of parallel lines upon a surface consists of congruent lines, on the grounds that it appears thus to vision, he would be forgetting that the fact must also be demonstrable to a blind man. Our consideration of the congenitally blind person suggests two other cases, namely, that of a man who has had vision since his birth, but never touch, and another man in whom the senses are perpetually in contradiction. One could ask if the first was able to recognize objects by touch with his eyes bandaged. It is clear that geometry, supposing him to be versed in it, would provide him with an infallible means of finding out whether the two senses agreed with each other or not. He would have only to take the cube or sphere between his hands and use it to demonstrate theorems, and if he were understood, he could then say which object it was. If on the other hand he was ignorant of geometry, I think it would be no easier for him to distinguish the cube and sphere than it was for Molyneux's blind man to distinguish them by sight. As for the person in whom the sensations of sight and touch are perpetually in contradiction, I do not know what he would make of form, order, symmetry, beauty, ugliness, etc. He would in all respects be placed with regard to these things as we are to the real extension and duration of phenomena. He would say, in general, that a body has a shape: but he would tend to think that it is neither what he sees nor what he feels. Such a man would have good reason to be discontented with his senses: but with regard to objects his senses would be neutral. If he were inclined to blame one of them as a deceiver, I think that he would pick upon touch. A hundred considerations would incline him to think For the relevance of this to Condillac's statue, see Vernière (ed.] 144 note 1. 57