Re: The Lunar Paradox

On Fri, 28 Nov 2003 20:54:59 GMT, "Craig Franck"
<[EMAIL PROTECTED]> in comp.ai.philosophy wrote:

>"Lester Zick" wrote
>
>>                                  The Lunar Paradox
>
>[...]
>
>> Now Glen dismisses all this contemptuously as irrelevant. As far as he
>> is concerned the illusory effect is simply not there at all so there
>> is nothing to be explained. But in order for this to be true there has
>> to be some reason I and others see the paradoxical effect if it is not
>> the result of atmospheric lensing or some other comparable effect.
>
>What is happening is the moon is being integrated into the visual
>plane of the horizon. The image of the moon as an object you're
>looking at is literally moved forward.
>
>Take a quarter and hold it at arms length and then move it halfway
>toward you while focusing on some background object (you will
>probably have to close one eye to get both the quarter and back-
>ground in focus). The quarter doubles in size in relation to the
>background. This is what happens in the lunar illusion, only with
>the moon instead of the quarter.

But why wouldn't one expect the size of the quarter to double? That
doesn't strike me as an illusion. It just subtends twice the arc at
half the distance.
>
>The fact that we can do this is related to size constancy; our
>visual apparatus seems more concerned with keeping the size of
>objects constant regardless of the size of the image on the retina
>than it does in rendering a true presentation of the light that enters
>our eyes (trust me, you wouldn't want one). It follows from this
>that it can monkey around with size and other things almost at
>will:
>
>http://www.comp.leeds.ac.uk/ugadmit/cogsci/percept/pages/percon.htm
>
>This also makes the visual volume of space around us non-
>Euclidian, which is a strong argument in favor of representational
>realism (we perceive the world through representations in our
>brains.)
>
>> But what I find really peculiar is
>> the inability and even unwillingness of those who deny the effect to
>> explain the effect and the origin of what it is they are denying.
>
>I believe it's mostly semantical. The exact status of the distinctions
>our perceptual systems make can vary from all of reality to non-
>existent depending on who you talk to, yet we all perceive more
>or less the same things.
>
>I view things such as colors as information processed by our
>brains, but there are obviously no colors in the brain that
>corresponds to them (a neuron doesn't turn red when I view a red
>spot). Also, while neurons do fire in patterns that are somewhat
>similar to what we perceive as shape, how the size is coded isn't
>quite known. A bigger moon might have more neurons firing, but
>it's the subjectiveness of the one doing the perceiving that counts
>as experience, not a neuron-by-neuron description of my brain
>activity.
>
>-- 
>Craig Franck
>[EMAIL PROTECTED]
>Cortland, NY
>
>



Regards - Lester