Thursday, February 17, 2011

A Braille eye (thought experiment)

Imagine the following scenario. Instead of light rays, the page of text before me throws out a film consisting of a braille version of the page, which somehow reaches my eye (Lucretius has a similar idea, though without the Braille). Unlike light, this film is solid and can be felt. Inside my eye is a miniature finger that moves across the film until it finds the word it was looking for (for example ‘dog’).

Two questions: (1) what is the proximate object of my search? Is it the film itself, which the miniature fingertip is feeling its way across? Or is it the original text which emitted the film? (2) How actually is this different from the way that my fovea searches the retinal image? The image stays constant and fixed while my retina moves around it – rather as though the fingertip were attached to the eye, and I had to move the whole eye in order to move the fingertip.


Brandon said...

The proximate object of your search is the word in question. But I take it you meant the proximate object of the operations of the eye, in which case I think it depends on whether you are talking about the eye muscles or the miniature finger; in each case it is (1) the leftward or rightward direction or something similar and (2) the elevation of that area of film that can be immediately detected by the finger, respectively.

The example reminds me of the blind man in Descartes's Dioptrics (Descartes didn't think the image was a proximate object of the eye, either, or at least can be interpreted as denying it).

Edward Ockham said...

>>The proximate object of your search is the word in question.

Correct (my sloppy). But is the proximate object of my search the word in the film, or the word in the text in the 'outside world'. Both the eye muscles and the miniature finger are instruments, and I am the agent.

I vaguely remember Descartes' example - can you remind me? I did this for a thesis years ago.

David Brightly said...

Not sure where you are heading with this, but systems have been devised to offer blind people some sense of sight by means of touch. See here for example.

>>Unlike light, this film is solid and can be felt.
Light carries energy and momentum. How much solidity do you want? :-)