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.

    211/236 (page 195)
    AFTERWORD: RECENT DEVELOPMENTS the recovered blind do not see visual illusions is that there is a counter-claim by R. Latta, who reports the study of a patient operated upon by Dr Ramsay of the Glasgow Ophthalmic Insti¬ tute: On April llth, 1904, Dr. Rivers and I tested quantitatively Camith's perception of certain illusions. Many of the tests failed owing to his imperfect development of the power of grasping [sic] lines and figures as a whole and to his difficulty in interpreting figures representing three dimensions. But in the case of the Müller-Lyer illusion and that of the comparison of horizontal and vertical lines, the results were essen¬ tially similar to those which appear in persons with normal vision.^® This finding is of particular interest, for in other respects Car- ruth show^ed very much less evidence of normal vision than S. В., and seems to have resembled the patient described by Ackroyd, Humphrey and Warrington in continuing to live the life of a blind person. We may conclude that studies of visual and hap tic illusions, although of great interest, have done little to answ^er Molyneux's question. Until the mechanism of the illusions is understood, the significance of their occurrence in the blind must remain problematical. Studies of cross-modal transfer in general, with the possible exception of those by Bryant on young babies, have done little either to support or disprove the theory of 'general ideas'. Section 6: Sensory substitution One of the most direct vvrays to investigate what the senses have in common is to stimulate one of the senses with the information normally supplied to another, and to find out w^hat is perceived through that sense. For example, what would happen if a visual image could be made to stimulate the skin? Attempts to stimu¬ late the senses artificially go back to the earliest days of electri¬ city, when it was realized that the nerves could be activated by an electric current. Helmholtz describes one such early attempt as follows: Le Roy passed the discharge through a young man who was blind from a R. Latta, 'Notes on a case of successful operation for congenital cataract in an adult', British Journal of Psychology, i (1904) 135-50. 197