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Neat optical illusion

CFLarsen said:
Hey, Ian! Do you still thing the two grey squares are not the same shade of grey? :)
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Did he deny it even after being shown the truth? Did he try chopping out a bit of square A in a graphics program and dragging it over B? :-D

I find the people who most vehemently defend indefensible positions are usually those least willing to try simple experiments for themselves -- experiments that would quickly demonstrate what's going on.
 
Huntsman said:
Meffy:

IIRC, his actual argument, after getting past the "I'm right because you're all idiots!" stage, was that color is, specifically, what the brain interprets, and not what is actually there.

Thus, to him, it really is a different shade until you move it.
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Or, he couldn't believe it was different, tried it in Photoshop, realised he was wrong, but had gone too far to back down so invented a ridiculous argument to try and support his ailing position?
 
tkingdoll said:
Or, he couldn't believe it was different, tried it in Photoshop, realised he was wrong, but had gone too far to back down so invented a ridiculous argument to try and support his ailing position?
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[heavy sarcasm]That doesn't sound like Ian.[/heavy sarcasm]
 
tkingdoll said:
Or, he couldn't believe it was different, tried it in Photoshop, realised he was wrong, but had gone too far to back down so invented a ridiculous argument to try and support his ailing position?
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Ian's argument was consistent with his position in other threads. Huntsman pretty much got it.

From a materialist perspective, the job of science is to understand the discrepancy between what is observed, which changes, and what is physically there (which we define as "real"). From Ian's idealist perspective, the job of science is to understand the discrepancy between what is observed (which we define as "real") and what is physically measured (which may differ for stimuli which are observed to be the same). It is a perfectly good philosophical position from which to explore the same questions as science does when approached from a materialist view. The job of connecting "out there" with "in here" is the same; the axiomatic assumptions of "what is real" are different.
 
Mercutio said:
From a materialist perspective, the job of science is to understand the discrepancy between what is observed, which changes, and what is physically there (which we define as "real"). From Ian's idealist perspective, the job of science is to understand the discrepancy between what is observed (which we define as "real") and what is physically measured (which may differ for stimuli which are observed to be the same). It is a perfectly good philosophical position from which to explore the same questions as science does when approached from a materialist view. The job of connecting "out there" with "in here" is the same; the axiomatic assumptions of "what is real" are different.
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I basically agree, but things get sticky when "what is observed" changes as we vary the observing apparatus (senses), because it is not clear where the boundary between the observer and the observed lies.

For example, consider the "deepest" part of my visual mechanism, the part that is fooled by the checkerboard illusion. According to Ian, that deep mechanism is part of the observed, not the observer. But would you call it part of the stimuli of the illusion? Tricky, that.

~~ Paul
 
Thanks to all for the clearing-up. Ian's world certainly is... erm... interesting.
 
That dragon illusion is awesome. I printed out the PDF and made one of my own. Thanks for the link!
 
Paul C. Anagnostopoulos said:
I basically agree, but things get sticky when "what is observed" changes as we vary the observing apparatus (senses), because it is not clear where the boundary between the observer and the observed lies.

For example, consider the "deepest" part of my visual mechanism, the part that is fooled by the checkerboard illusion. According to Ian, that deep mechanism is part of the observed, not the observer. But would you call it part of the stimuli of the illusion? Tricky, that.

~~ Paul
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Actually, I think Ian has been quite consistent on that. The explanations for that illusion (as well as the Muller grid illusion) rely in part on the structure of perceptive fields in the retina, which (through a differential center/surround positive and negative feedback mechanism, which I can explain but which is not the point here) mechanically (close enough) makes edges more salient, makes colors dependent on their surrounding colors (where "color" is defined subjectively, not by wavelength), and can be modeled mechanically quite easily (probably already is being used in mechanical vision for robotic uses, but I don't know that--it is a tremendously useful little trick). Likewise, the spectral sensitivities of the alpha, beta, and gamma photopigments can also be modeled mechanically and used to describe how differing combinations of wavelengths can be associated with the exact same experienced color.

In both cases (receptive fields and trichromatic theory), the sensory apparatus mechanisms are part of the illusion (indeed, it would not happen without it); both are part of what Ian's ideal observer must experience. Both, to Ian, are part of the outside-of-observer, seemingly physical (although I think Ian would perhaps argue that we cannot assume they are physical, since the only evidence we have for them is experiential) world. Ian's observer is not dependent on such things, but on the experience itself.

It takes a great deal of effort to understand Ian, but I find it quite worth it. (I do not guarantee that my explanation is the same as his--some may be my interpretation of his view...also I am in a bit of a hurry right now, prepping for class.)
 
Neato supremo, but the dragon one doesn't really seem to have the effect it's going for. I can tell it's concave, and I think that's the problem. Another part of it is I was first exposed to this sort of illusion when I was like... 4 or something, so I think my brain adapted rather well.

The rest work great.
 
alfaniner said:
OK, whenever this subject comes up I always like to bring out this one. Look closely and note which side has the angry face.
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If i look at it without squinting, they both look angry to me. But i have really bad eyesight, and my glasses tend to distort things a little.
 
I recall reading somewhere that some types of schizophrenics are not able to be fooled by some sorts of optical illusions. Something about the way their brain fails to filter then normally; which may be linked to the mechanism responsible for paranoia as well. I can't seen to find the study in my links.
 
Dark Jaguar said:
Neato supremo, but the dragon one doesn't really seem to have the effect it's going for. I can tell it's concave, and I think that's the problem. Another part of it is I was first exposed to this sort of illusion when I was like... 4 or something, so I think my brain adapted rather well.
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Try keeping one eye closed as you look at it.
 
Considering it's a 2D image on my moniter... how exactly would that help? :D I'm merely saying that though I know the illusion is based on depth perception, in looking at it on my moniter the only depth can be provided by my brain's interpretation and not two viewpoints, so I doubt that my being able to see the actual depth perception was what threw it off. I just think it's the nature of how when something moves back and forth like that it immediatly jumps out at me as "concave", because it doesn't look right to my brain.
 
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