Wednesday, August 22, 2007



Does Colour Exist?




This is a question that has bothered me for some time since learning that all colours are merely the different wavelengths of colourless light. It seems that an object's absorption, reflection or scattering of pure light will determine it's colour. An object that scatters light completely will be white, while an object that absorbs all light will be black. Other objects, depending on the way in which they reflect, scatter or absorb light, could be any colour in between. Now to me, this seems like a fundamentally important concept with important repercussions for the everyday manner in which we think about phenomena. Most of us, when the lights go out, are convinced that the colours of the objects that surrounded us in the presence of a light source, are "real". That is to say, we do not doubt that the wall of our bedroom is blue, nor that our bed coverlet is green and the curtains yellow: it just happens that for a spell the light is turned off and we can't see these colours. However, it would be more true to think that without a light source, all objects cease to have any colour at all. In a universe where all the stars suddenly went out, there would be no colour. Colour would not be a property of objects that existed in the dark. Perhaps colour might be compared to the fine clothes we like to display ourselves in. They are pretty, but have no real connection to the man or woman beneath the clothes. The only reason why certain objects seem to have a certain constancy of colour is due to their properties as spatially extant things. For example, a rough, hard surface will often absorb light in a particular way to appear more or less brown to us most of the time (trees, furniture, wood, etc). However, the object is in no way really "brown". "Brownness" is merely a temporary attribute of its appearance for as long as it interacts with a light source. To illustrate this idea still further, certain birds, insects and fish have eyes that are more "colour sensitive" than ours and experts insist that some little dull brown birds, are filled with the most gorgeous colour in the eyes of the other birds! In a similar way, scientists have also suggested that birds are able to follow migratory patterns so exactly because they are able to physically see the colours of the magnetic field surrounding the earth (wavelengths beyond the perception of the human eye).

Presumably "vision" is a quality of a universe that is lit by star power. Without stars, light wouldn't exist and nor would colour. We might further speculate, that living organisms develop the attribute of "sight" (and eyes as physical organs) in a universe that has been created (or has created itself) in order to be seen. If light didn't exist, nor would eyes and no doubt we would all be eyeless and sightless as are some creatures that live deep in the ground or deep in the sea. Of course, without light there would also be no warmth, so only the most barren of universes could be contemplated that didn't have "vision" as one of its attributes. Perhaps current ideas about temperature and what is hot and cold might be totally rearranged in a universe without star power. Nevertheless, this is mere speculation and, to tell the truth, it is really impossible to imagine a universe that doesn't possess the star power to give heat and light.

3 Comments:

Blogger ely said...

A very thoughtful and difficult argument.

10:14 AM  
Blogger options07 said...

Check out |Edwin Land's experiments:
http://www.physicstoday.org/vol-55/iss-7/p43.html
search term :
Land on Colour

7:39 AM  
Blogger Medway said...

colour is very much in the eye of the beholder, John.
I think it quite easy to imagine an alien race with a totally different colour perception...in fact there are plenty of animals right here on Earth with different colour perception to us. Better to worry about numbers... Can we imagine an alien race that has a different number system to us? Would their alternate math work in the same universe?

10:49 PM  

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