a rainbow requires an observer

light is tricky because it can either be particles or waves (apparently).
if light is considered solely as waves then yes.
the "tree in the woods" analogy is the same thing.
the tree produces the waves but the sound will be absent without the observer.

a similar analogy would be the transmission of radio and TV programs.
without the proper observer, a radio or TV, the programs will never be seen or heard.

 

Log in or Sign up to hide all adverts.

Yes, good point, I actually had in mind the animals, such as certain insects and birds, that have ultraviolet perception. It's conceivable that all the colors we see would fit into that animal's perception in the way we see shades of red. (Assuming it sees them at all). That's sheer speculation, but one that considers what we might see if we looked through a system that compressed our visible range into the red band in order to reserve space for the shades of ultraviolet, which the system might remap into the bands that we perceive as orange through violet.

It remains an intriguing mystery as to how the continuum of wavelengths "appear" in the mind as hues. It does seem that in general each sighted species is endowed with a perception of spectral differentiation that has a benefit of distinguishing specific markers for essential needs such as food, mate, and camouflage. This, and perceptions like shape and patterns, are part of the larger question of what it means to assemble the pulses from the optic nerve into the phenomenon of sight, through many functional layers, resolving into the visual experience itself.

Now that PET scanning gives some clue about how brainwave patterns correlate to particular images (presumably a person looking at a rainbow might exhibit a particular pattern) we are practically left on the doorstep to continue to ponder what it really means to perceive anything at all.

 

Log in or Sign up to hide all adverts.

Yes, I understand now you are addressing perception. I thought Epictetus was asking whether refracted light would propagate at all without observation. I thought maybe he was inviting discussion of what observation means. At first I thought you were requiring perception in order to have observation in that sense. I asked about sky light since it would necessarily be the result of atmospheric refraction.

I was prepared to offer a chloroplast as an observer. It then occurred to me that refraction within the lens and vitreous humor of the eye, and then again at the nerve net in the retina where at last the photon sets up the electrochemical propagation of a colored pixel down the optic nerve, would present the argument that all visual perception is of refracted light.

I see now that you were simply addressing perception.

 

Log in or Sign up to hide all adverts.

I don't understand how you not seeing it makes it not there. The wavelengths are still scattered if your there or not.

 

If the waves are there, the sound is there plain and simple. If I put a microphone there to record the waves and play it back I hear the sound. There same information is present whether or not someone is there to hear it.

 

In my opinion there are two distinct plans.
One is the reality and another is our perception and reflection of this reality in our mind.
It would be interesting to analyze the interdependence of these two plans.
Especially if our perception and reflection in our mind, change the reality.

 

How is saying this any different then saying if no one oberserves the sun it is not there? Both are physical phenomena that don't need you.

 

I wondered often, how we would perceive the reality if we would have more sensors.

Electroreception , Magnetic-field perception , Non-human senses

 

It would look cool for a while I'm sure, but would the information be useful or just confusing?

 

At best that is only partially true, but mostly false. Yes if a "white" sheet of paper is illuminated by one narrow band of visible wavelengths, it will produce some neural activity in all of the three retinal detectors. The relative intensity of these three channels is what make you call it for example yellow.

However there does not need to be any of that wavelength band entering into your eye for you to see "yellow." By careful adjustment of the intensity of three different wavelengths (say each one at the wavelength of the peak sensitivity of the three different color receptors), you can again make the identical relative neural activity in the three channels. That is all your brain has to work with, so of course you will again perceive the light as yellow.

Edward Land, inventor of the polaroid film process developed a theory of color called Retinex Theory of color. Details at: http://www.trincoll.edu/depts/ecopsyc/courses/retinex.html

Which exploited this fact (closely related to "color constancy" - fact that a leaf still looks green even if the illumination has no "green" light say when only illuminated by the very reddish orange setting sun). Here is an image with only red wavelengths + uniform white light, but parts of image definitely are not just different intensities of pink.

Please Register or Log in to view the hidden image!

"This idea was first demonstrated by Edwin Land, the founder of Polaroid, in 1959 by using two slide projectors. Each projector had a black and white slide in it, and one projector had a red filter in front of it. Oddly enough, recent updates of psychology textbooks seem to omit any mention of this experiment." image and this quote from: http://people.msoe.edu/~taylor/eisl/land.htm

Land gave this demonstration (and many others) while speaking at JHU. I was an amazed graduate student in the audience, as prior to his visit I believed falsely what most believe: I.e. that wave lengths present determine the perceived colors.

By the way you already know the simple theory you believe (wave lengths present determine color) is false. Just take piece of green paper, cut it into two small pieces. Place one on large blue sheet and the other on a yellow sheet - the two greens will be very different in perceived colors.

Summary: color perception is far more complex than most believe. Part of the reason you see leaves as green in the setting sun light, is you know the leaf is green. To remove this "knowledge effect" experimenters use different size adjacent rectangles each with different spectral reflectivity (but some pairs identical), called Mondrian patterns. More on them, "color constancy" & Retinex theory here: http://www.neuronresearch.net/vision/files/retinex.htm

 

I personally would want. About others I can not pronounce.
(How about an electrician with electroreception, or a sailor (explorer) with magnetic-field perception !?

Please Register or Log in to view the hidden image!

)

 

and that's the point.
the sensation of sound is not a physical phenomenon.

 

I wouldn't say what I said was false, just that it's not the complete story and the color can be influenced in other ways, but these thing of which you speak have to do with your PERCEPTION of the color, if the wavelength is there, the color is still there. If you take a spectrometer and measure the spectrum coming off of the green paper in your experiment, its still green. The overwheleming blue simply confuses your visual processing. The wavelengths are still determining the color either way. If you put another color of paper that was also capable of changing your perception of the green paper, would it not be a different color percieved then if it was on the blue paper? The wavelengths are not changed, only your perception of them and I would bet that this perception change is related to the other wavelength present, which still means that the wavelength determines the color.

 

Sound is the movement of air molecules, how is that not physical????

 

uh, the transverse waves are the physical phenomenon.

 

No you are so convinced of the false idea that you confuse wavelength with color.

For example a "color blind" person (or non human) does experience the same wavelengths but not the experience the same color. Even just your memory can change the color you perceive. You can perceive blue color when there is only uniform white light present. (Just stare at a bright yellow spot for a minute, then look at the white wall.) Of course if you had stared at bright blue spot for a minute then exactly the same light from the white wall will cause you to see yellow spot. Ergo- wavelengths need to be present but do NOT determine the perceived color. Thus the only truth in your statement I numbered (1) is:.

(1) If no wavelengths are present then you see no color.

Point I was trying to get you to understand was that no matter what set of wavelengths is present, if their intensities are adjusted to make the same relative neural activity ratios in the three different color receptor cells as when only single wavelength we call yellow is present, you perceive yellow EVEN IF NO WAVELENGTHS EVEN CLOSE TO YELLOW LIGHT ARE PRESENT.

(2) Yes the wavelengths (and their relative intensities, plus 6 or more other factors) do determine the color perceived but their is no simple connection between wavelengths present and color perceived.

 

Your confusion is most clear here. There is no color with, in, or at the spectrograph - only EM energy of some wavelength. Color is NOT same as wavelength. Color is sensation, a qualia, created in a brain.

You do not have any "perception of the color." Color IS a perception, just like fear, pain, etc. and other qualias

 

No, you are still confused. Sound is a brain created qualia, sensation. What is physical is the compressive density wave traveling it the air, usually.

 

Can't win um all I guess

Please Register or Log in to view the hidden image!