Gordon Globus states or supports several notions about perceptions that do not seem correct to me. For instance Globus indicates that
...Introspect as hard as you like, all you'll ever find is colored surfaces, never any visual sensations going on inside...they are all world-related, not in consciousness, not going on inside of us but out there in the world.
If that is correct, then where are optical illusions? Certainly not in the world outside! How do ambiguous figures arise? What happens to a Nekkar's cube when I "flip" my perception from one cube to another? Nothing changes "outside," just "inside".
Globus writes:
...the painful thumb is right there next to the nail...
but what about phantom limbs. There is not painful limb for those who suffer this problem. Again, the pain is "inside."
Globus supports Gibson's view that
The color of things is on their surfaces,...not in our minds.
and goes on to state that:
Electromagnetic frequency and object color nicely correlate...
Actually, they do not. When we see an object as "red" we are not simply seeing red wavelengths of light from the object. Rather our perceptions exhibit color constancy. That means that we will continue to see an object as "red" over a range of input intensities of light of different wavelengths. We do some kind of averaging for the total input of different wavelengths of light across our whole visual space to determine color of an object, as Land, Zeki, and others have demonstrated. It is possible for there to be more green light coming from an object than red light and for us still to experience the object as "red."
David Wilson
dwilson@umiami.ir.miami.edu
jcs-online
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