[FOM] colour or colours

Paul Hollander paul at paulhollander.com
Sun Nov 6 12:28:54 EST 2005

Richard Heck, 9:17 PM -0500 10/31/05:
>Suppose Bob says, "That ink is blue". Suppose context shifts and he 
>now says "That ink is not blue". Has Bob contradicted himself? Have 
>his beliefs changed? Not necessarily, and certainly that's not how 
>Searle wants us to take the example. It's the context that's 
>shifted, not Bob's beliefs.

A.R.D.Mathias, 5:10 AM +0400 11/2/05:
>I haven't checked recently but there was a time when under certain 
>conditions (usually when I was fatigued and had been lying on one 
>side for some time) my two eyes perceived hues, if not colours, 
>differently. One would see an object as a rich red, the other as a 
>watery red. Which eye was correct?  I always assumed it was 
>something to do with differences in the blood supply to the
>two eyes, as if I changed position to lie on my other side, the eyes 
>would, given a little time,  exchange perceptions.

Anyone who uses color thought experiments in philosophy should be 
aware of the work of David Williams at U. of Rochester.  Williams 
provides evidence that color perception, as measured by having 
subjects calibrate a light source to pure yellow, has both greater 
regularity and greater plasticity than can be explained by eye 
physiology alone.

A recent press release from U. of Rochester 
(http://www.rochester.edu/news/show.php?id=2299) describes William's 
two most recent findings:

"Williams and a postdoctoral fellow Yasuki Yamauchi, working with 
other collaborators from the Medical College of Wisconsin, gave 
several people colored contacts to wear for four hours a day. While 
wearing the contacts, people tended to eventually feel as if they 
were not wearing the contacts, just as people who wear colored 
sunglasses tend to see colors "correctly" after a few minutes with 
the sunglasses. The volunteers' normal color vision, however, began 
to shift after several weeks of contact use. Even when not wearing 
the contacts, they all began to select a pure yellow that was a 
different wavelength than they had before wearing the contacts."

'"We were able to precisely image and count the color-receptive cones 
in a living human eye for the first time, and we were astonished at 
the results," says David Williams, Allyn Professor of Medical Optics 
and director of the Center for Visual Science. "We've shown that 
color perception goes far beyond the hardware of the eye, and that 
leads to a lot of interesting questions about how and why we perceive 


Paul J. Hollander
Visiting Lecturer
Corning Community College
Corning, NY

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