From Edmond Wright
I should like to point out that Kevin O’Regan’s claim that we do not experience colour inside our brain and that, therefore, all our experience is perceptual, has not gone unchallenged (29 January, p 40). As I pointed out in a commentary in Behavioural and Brain Sciences, where he and Alva Noë put forward this view, it makes the error of ignoring the patently empirical fact of internal sensation.
Take this example: a little girl aged five experiences an after-image. She does not know that it is an after-image – indeed she experiences it for a moment or so without actually paying it any attention. However, happening to close her eyes, she does come to notice it, but only as a meaningless splodge among other meaningless splodges.
But after a second or two, she notices that it is in a hexagonal shape. In this same instant she realises that her mother has brought her up her favourite sweet as she usually does, and that it is on the silver hexagonal dish that she usually brings it on, and that she has placed it on the window sill in the bright sunlight. So at last she has perceived with the aid of her sensation. She opens her eyes and goes and gets the sweet, that before she had not realised was there.
Unfortunately for O’Regan’s thesis that there is no such thing as internal sensation without attendant perception, here we have a counter example, for the child first experienced internally a “raw-feel” sensation (for everyone admits that after-images are not in the external world), then noticed it, still as meaningless, then at last used her perceiving mode to project upon that internal experience an “objective” interpretation.
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If this is possible for after-images, there is nothing to prevent us claiming the same structure for ordinary open-eye visual sensation: that it is fundamentally meaningless, internal, and open to experimental changes of perception.
From Ian Jackson
Your article described a blind person “seeing” via a tactile pad on the tongue. It is good to see this development in real life. I first read about this concept in the science fiction story The Persimmon Sequence published 34 years ago by Don J. Fretland, where a compact head camera and tactile pad was used by a blind character to “see” basic shapes at low resolution. The only significant difference in the story is that the tactile matrix pad was strapped to the inside of the upper thigh and provided feedback through skin sensitivity.
Drouin West, Victoria, Australia
Cambridge, UK
