What Colour is an Orange in the Dark:

They don't "trick the brain." An orange has wave length varying reflections coefficients, but no color. Color is ONLY created in the brain.

Further more what that color sensation is, depends on the brain. It is not the same for a honey bee, as for a gold fish or a human with only 2 or the three wave length sensitive retinal cells types and even "normal humans" have slightly different color experiences as there are two slightly different green sensitive retinal cells - Different peak sensitivity wave lengths, etc. (If I recall correctly, the gold fish is basically sensitive to the same visible band of EMR, as humans, but they have four, not just three, differently wave length sensitive retinal cells. - I.e. from the gold fish's POV, all humans are "color blind" - missing one of the four different sensor cells.) We call a human with only two: "color blind" and they do experience color differently than normal humans do.

Yes you do. You think objects have colors but they only have different reflection coefficients. What color sensation white light reflected by them creates depends upon what creature is viewing them. As I have noted white flowers have reasonable constant reflection coefficients in the visible (to humans) wave length band, so appear "white" in color to non-color blind humans, but have very different colors to most insects that are UV sensitive.

COLOR IN NOT A PROBERTY OF OBJECTS. (Only reflection coefficients are.) Like beauty color is in the brain of the viewer, for humans in the V4 region.

 

Log in or Sign up to hide all adverts.

That is 100% correct. There is no way to compare any of the sensations caused by the same stimulus in two different humans; we only ASSUME that they are similar based on the known similarities of the processing systems. We do not make that assumption when the processing systems differ - for example a person with only 2 of the 3 wave length sensitive cells. Further more we know their sensation are at times different from a normal humans as they can not tell any difference between two EMR stimulations that the normal can.

In the philosophical literature there are many papers discussing conceptually what the color experiences one would have if while they sleep, a mad neuro-surgeon exchanged the neural fibers in the optic nerve that send signals about red and green. Most agree that upon waking, the victim see grass as red and setting sun as greenish. And also for the reason you mentions, what causes red color sensation in one person may be a very different sensation than taking place in a different person, but both have learned to call these color sensation "red."

So after living with his swapped neural connections the victim re-learns to call the sensation that initially he call red (when look at grass) green. Then that crazy neuro-surgeon get to operate on him again, undoing the reversed connections he made earlier. Thus his visual neuro system is as all other humans, so presumably so are his visual sensations, but he now calls the color of grass red.

The main point of this hypothetical experiment is exactly the same as your point. Just because we tell others is the color we are experiencing is red, even if we have basically the identical neuro-anatomy, does not mean our experiences are the same.

 

Log in or Sign up to hide all adverts.

I believe you are wrong, totally. Please explain the white Opera house shells at night under laser lights of different colours.......Please explain

How and why the Moon appears so much bigger on the horizon than directly overhead if the brain is not tricked......Please explain that while all frames of references are valid as each other, the light frequency/colour of anything within a gravity well, will appear different to two different observers, if as you say the colour was the sole property of object.

No I don't, and you have already confirmed that colour in the first instant depends on the EMR present. People that are colour blind, or have some other physiological disorder may be limited in the way that their brain perceives light but if their is no light, there is no colour.
Heard of Newton? The composition of white light? VIBGYOR....Every other colour can be gauged by whatever receptive properties of an Orange or anything else reflects.....If there is no light, there is no photons to be reflected, ignoring infrared, ultra violet and microwave emisions/wavelengths.

 

Log in or Sign up to hide all adverts.

Let's do another experiment.
I put an object in a totally darkened room.
I invite you to walk into that room and tell me what the colour of the object is.
The obvious answer is you are unable to discertain the colour of the object.
All you see is black. Black is the absence of colour. Colour is what we perceive from white light and whatever reflective properties the object has.

All we can say in the case in question with an Orange, is that very probably the Orange was Orange before the lights went out, and will be Orange again when the lights go on, but while it is dark/no light, it is black, although it could be said that it has the "potential" of being Orange. But as per my experiment above, if the object is unknown, than one cannot discertain its colour in the dark.

 

But whatever colour the brain decides to create, depends on the type of EMR falling upon that body, then the part of the spectrum the property of the object decided to reflect to your eye ball, that is than transferred to the brain.

 

Sometime true, but at least you no longer claim the EMR is the color. I.e. you now admit color is a creation of the brain, not part of the object seen.

I have given several (four color after effect cases) where the identical EMR entering the eye can result in the very different color sensations we call, red, green, yellow or blue, depending on what recently EMR has been stared at under intense illumination.

I have also noted that the reflectivity of surfaces adjacent to the fixated area, partially controls the color experienced, also even when exactly the same EMR is entering the eye.

I have also noted that no EMR needs to exist to enjoy color sensations - I.e. even with eyes closed in a dark room most people can experience all color sensations by memory recall, like remembering the color of your first car, which no longer even exists or in the dreams.

Thus color sensation does not depend upon the EMR currently entering your eye, but it may.

BTW, your phrase "that is then transferred to the brain" is not correct - neural signals from the retina cells are transferred to different parts of the brain via the optic nerve, the optic track, the LGN and from there most go to V1 but small fraction go to the superior colliculus, which allows "blind sight," especially well developed in monkey, even if V1 is destroyed - I.e. the human or monkey is "cortically blind."

 

Please Register or Log in to view the hidden image!

I have never said the EMR is the colour.
All I have ever said, is that in the first instant, the colour of any object depends on the type of EMR that falls on a body.....then secondly, the reflective properties of that body, then thirdly your baby, of our the brain interprets that reflection...nothing more, nothing less.

What people imagine, what they think are essentially variables within their brain. That does not change the fact that colour of any object in that first instant, depends on EMR.

You seem to want 2 bob each way. And you still have not answered or referenced any of my examples as to why the EMR is the first and primary concern.

I stand humbly corrected on using the word "transferred" but it certainly does not change the fact that no light, no reflection, no colour.
You have yet to answer my experimental question.

 

Do people who have been blind from birth ever dream in colour?

 

Good question.

 

I have said the EMR entering the eye is normally strong correlated with the color experience created but does not exclusively determing what that color experience will be - other factor and strongly influence what color is experienced.

.The brain is not "tricked" however your perceptions are not necessarily accurate. There is the well known three bucket demonstration of this. One bucket is full of very hot water, and another with ice water. The third is at room temperature. The left hand remains in the hot water for several minutes while the right remains in the 0 C water, then both are placed in the room temperature water. The left hand is telling you that water is cold and the right hand that it I warm. This is why we use instruments to do science - human experience is easily mislead about the actual facts. The "moon illusion" is interesting as no truly satisfactory reason for it exist - I have read an entire book on only the moon illusion, and yet have my own theory about why it happens.

The part now bold is perhaps the most fundamental postulate of physics,* and very well confirmed. I think you have a reading or typing problem as I have repeated said color is not even a property of any object, much less not the "sole property of an object." AGAIN: COLOR IS A CREATION OF THE BRAIN

* Relativity both general and special, follow from it and without that postulate, physic handbooks could not exist as the earth is constantly changing from one frame to another, as it goes around the sun.

 

AFAIK no.
Their dreams are largely tactile and olfactory, but may have music / sounds also. Possibly even tastes too but I never have any taste experiences in my dreams so doubt that but they would, but they could, especially if cooking is an important part of their life.

Quite often a large part of the posterior cortex normally taken for visually processing is utilized in the congenitally blind for other processing. The young brain is very "plastic." -The term used.
There was a two or three year old girl at JHU hospital with "status epilepticus" ( many seizure each hour) that evolved one side of her brain only, so that entire side was removed. As far as simple observation tests and behavior tests were concerned - she developed normally!

In cat there is an amazingly short period in which they must actively see - 6 weeks as I recall. Two baskets were hung from opposite ends of a central pivot horizontal beam. Both basket bottoms just cleared the floor and one only had holes in it so that cat could walk and make the beam rotate. There was a circular wall surrounding the path of baskets. If there were random oriented short lines on the inside of that wall, the "walking cat" acquired normal vision but the passively riding cat does not even though it eyes are exposed to exactly the same visual stimulation as the "walking" cat. If there are only vertical contrast stripes on the wall, even the walking cat's acquired vision is seriously damaged - Does not form the horizontal "line detectors" Hubel and Wiesel got a Noble Prize for discovering* is part of the normal processing in V1.
If you suture closed the eye lids of a cat at birth, and do not remove them until the cat is two months old, that cat will be blind for the rest of its life.

* BTW, those detectors are not really line detectors although everyone, me included, still calls them that. What they are is part of quasi-Fourier analysis system. Every object you see is quickly resolved into to quasi- Foruier components in V1. That makes location unimportant for object identification and rotation of very little importance. I.e. the brain although "retinotopic" does not work in the 2D space, but in its Fourier transform space.

As they had no way to control what the monkey was going to look at, they surrounded it with uniflormly spaced parallel lines, so it made no difference where he looked. They found some cells that responded strongly to one orientation of the lines and very weakly to one 90 degree from that orientations and others cells that did just the opposite. Naturally they called these cells "line orientation cells," but a set of regularly spaced parallel lines has a very sharply spiked spatial Fourier transform too. More complex test show that they actually found 2D Fourier orientation analysis processors but few know this or how it is proven.

 

Let's here it. Start a thread if you like. My reasoning was that it occurred due to comparison in sizes to other objects on or near the horizon :shrug:

Not at all, but perhaps we are reading past each other. While I agree that colour is an interpretation/creation of the brain, it still depends on the visible part of the spectrum....and the answer you gave Daecon seems to back that view up imho.

 

It is short so here is slightly condensed version:
Humans naturally and automatically imagine there is a dome of the sky, as their ancestors did, despite their education which tells them that stars, etc. are not points on that dome.

They see high flying birds, clouds etc. rapidly moving with angular rate of change when their flight is over head, but much slower angular rate of change when nearer the horizon, so they naturally, automatically, conclude that the dome over head is closer to them than near where the dome comes down to the horizon. I.e. they automatically have a model of the dome of the sky, despite their education, that is like a "squashed down" sphere.

The moon and the stars are falsely assumed automatically to slide on this "dome of the sky" as was actually believed by ancient man. Thus the overhead moon is automatically thought to be closer to the viewer than when the moon is nearer to the horizon. Education can not undo automatic perceptual processes.

There is an automatic process, called "size constancy" that adjusts the perceived size of the physical size of retina images - to correct for their distance. E.g. when a man stands three times farther from you than his half grown son does, his retinal image is smaller than that of his son, but you correctly perceive that he is bigger despite his smaller retinal image size. Law of "size constancy" in operation. These automatic adjustments are not subject to conscious control - you can not, even if you try, perceive the man is smaller than his half grown son, as his retinal image is.

The retinal image of the moon is a constant size independent of where it is (over head vs. near horizon) but unconsciously all believe automatically (despite their modern education) just as their ancient ancestors did - that the moon is sliding on the surface of the dome of the heavens. As the near horizon moon on that "squashed down" surface is farther away, the law of size constancy automatically increases the perceived size of the near horizon moon, just as it automatically increased the perceived size of the man to be taller than his son, despite his smaller retinal image. That is why the moon near the horizon is perceived to be bigger than the over head moon.

PS your explanation would work, but not when you are on a ship at sea - no objects near the moon just above the horizon to compare with. (But you take your automatic "squashed down" sphere model of the dome of the sky, to sea with you.)

 

Often that is true, but not always as perception of color is a very complex process.

I have several times given examples of when not. Perceiving red, green, yellow or blue with exactly the same EMR is entering the eye. AND perceiving colors when there is NO light present (dreams, hallucinations, and even just memory recall with eyes closed of some colored object recreates "color activity" in V4.) AND, less dramatically due to different reflection coefficient of nearby surfaces, different shades & intensities of colors are perceived even though the EMR coming into the eyes is exactly the same from the two spots perceived to be different in color shade/ intensity due to different reflection coefficients of near by surfaces. - Artists knew and used this more than 100 years ago, but AFAIK Land was first to explain why scientifically.

 

Perhaps, but these quotes from your prior posts, certainly can be understood as a claim that the EMR is the sole cause of color sensations:

 

That appears to be BillyT's claim. He seems to be opting for a phenomenalistic theory, defining 'color' as a subjective experience, which 'only exists in brains' (whatever that means). 'Color' isn't a property of physical objects but rather is a property of human percepts (whatever they are). For BillyT, color appears to be purely subjective.

You (and I along with you) would apparently opt for a more realistic theory. When we ascribe color to an object, we are talking about objective facts about the physical world and not just talking about ourselves and our own personal psychologies.

The next question seems to be the question in the original post, the question of whether or not color is a relational property. Is color an inherent quality of the thing seen, or is it a function of how that object interacts with its environment?

You seem to be insisting that color is a relational property that's dependent on things like the color of incident light and the medium through which the light moves. Your white Sydney opera house appears brightly colored when illuminated by colored light at night. It would appear to be blue if observed through blue glass. We start to get into danger when we introduce words like 'appear', but this is still objective appearance, visible to spectrographic instruments as well as 'inside brains'.

It's a reasonable position to take, since we often do want to associate color with the wavelengths of light that objects actually are reflecting, and that depends on more than the physical qualities of the object doing the reflecting. The downside of looking at things in this relational way is that it makes a physical object's color dependent on circumstance.

Usually, when we ascribe color to something, we are ascribing an inherent physical quality to whatever we are talking about. We aren't talking about the whole situation, the incident light and the intervening medium. So in your Sydney opera house example, I'd be inclined to say that the building's color refers to the wavelengths it reflects in white light in a colorless medium. That way, any spectral bias in the wavelengths it reflects is a function of its own reflective properties. This is the answer that I'd opt for, since it preserves the constancy of the color property.

Because it's a philosophical question that exposes ambiguities in what the word 'color' is taken to mean. The best way to address it is by conceptual analysis, not by physical experiment.

 

You can only experience in your dreams what is already in your head - i.e. what you have already perceived.

I would make a distinction between imagining and experiencing. I can imagine leprechauns frolicking on the lawn but I wouldn't call that an experience.

You can remember it if you've seen it. If you have no EMR experience of "red", how would you know what it was to imagine it?

 

No what you can experience in dreams is much wider range of experiences, I and many people have experienced flying by arm flapping - physically impossible, or walking thru fire with no damage etc.

In fact no one knows why we and many primates at least dream (or at least have periods of REM - rapid eye movements). I have a hunch the reason why dreams exist is that then your actions are NOT physically constrained and you can more easily "think outside the box." I have often gone to sleep thinking about some problem I was having difficulty with - unconsciously constrained by my assumed assumptions as to what was possible. In the dream those constraints do not exist. Not rarely within the first hour of awaking the next day, I have a new approach to solving the problem - It just "pops" into my conscious mind. I think this may be why evolution has selected for dreaming. It should have some "survival value" to be so common.

I agree, but I was not speaking of tangible objects but of "experiences." leprechauns, unicorns etc. are NOT experiences but imagined objects / items.

In the case of remembered experiences of sensations, there is strong scientific evidence that the memory recreates activity in the same brain regions that the original external stimulus did - just not with the intensity or resolution that the external stimulus made. Do you recall what I said about the mental image of an imagined tiger?

 

You have experienced in your dreams what you have perceived in reality - flapping, walking, fire - but in combinations that are not possible.

 

Yes that was exactly my point when I said in post 78: " what you can experience in dreams is much wider range of experiences {in dreams that is physically possible.}"

I tend to think that one can imagine experiences not possible on earth - like leaping several times greater distances on the moon - which you have never had.