In physics, mass is a universal; one unit of mass is the same yesterday as it is today; as it is here or orbiting Betelgeuse; and if we accept the atomistic thesis then this result follows from the invariance of number; as implicitly pointed out in Lucretious On Nature.

Now consider a man holding a red apple; he sees before him a red apple.

Translate him in space; to Mars say; and ask him what he sees before him - it is still a red apple, he remarks (of course the lighting conditions that normatively obtain on Earth have to be set).

Translate him to Alpha Centauri, or to a small comet orbiting Betelgeuse: the same observation obtains; etc, etc.

Consider now translating him in time, to yesterday, or yesteryear or a thousand years ago; and again with the proviso that lighting conditions are made as on earth, he still remarks that the red apple in his apple still looks red, the same colour of red as before.

Thus, redness is a universal; but a universal that is spatial and temporal; and this is in line with Kants thesis that space and time are the conditions of experience.

But is it possible that redness as a universal can be a platonic form/essence (I'm not sure of the correct terminology here)? That is exist outside of space and time?

  • It is possible and it is. Same with sounds and smells. And so much more. – Asphir Dom Jul 31 '15 at 12:57
  • @AsphirDom: I'd say that a sound changes in time, which makes it difficult to conceive it in the same way; but the same argument above applies to pure tones; smells - I'm not so sure... – Mozibur Ullah Jul 31 '15 at 15:07
  • I would quibble with the notion that color is a-spatial. It is somewhere whenever you see it, and it occupies space in your visual field. Perception of it is much more dependent upon space than even the perception of space itself is. – user9166 Jul 31 '15 at 16:41
  • @MoziburUllah dont discard smells, it is well known/widepersonally checked that smell can bring even deepest/oldest memories and dejavues. Something to philosophe about. – Asphir Dom Jul 31 '15 at 19:55
  • @asphir dom: sure - la reverie de Madeleine; and it is. – Mozibur Ullah Aug 1 '15 at 11:42

Redness is traditionally known as a qualia. Your argument would thus be that a qualia is aspatial and atemporal, which has some merit.

I would argue that a qualia is independent of the environment, so in that sense it is aspatial and atemporal. However, it is not independent of the self. If your observer spent 7 years studying the nuanced facets of the color red in paintings, and was then shown the same apple, I would expect his qualia regarding the color to have shifted, growing more subtle in meaning.

Not withstanding the qualia of "redness," the actual photons hitting the eye may change from spatial location to spatial location. For example, if your observer took the apple 60ft under water with SCUBA equipment, they would still observe the qualia of redness. However, take a picture of the apple with a camera, and look at the picture in normal daylight lighting, and the qualia of what we see is more black-ish. If the camera is deemed a good measurement tool of color, and the print is a good reproduction of the colors measured, there must clearly be more than meets the eye.


  • Cort and @MoziburUllah, what grows more subtle? the meaning of qualia of red, or the qualia of red? or the qualia of meaning of the red? can you explain that in a way that makes sense? why the example of 7 years of nuanced studies of the color red in paintings, doesn't it change just as much from second to second as I recall all kind of different reds (traffic light, balloon), while watching a red patch? and what does red have to do with wavelength? I can also see bright amazing reds while dreaming, without any corresponding external light, underwater, or in orbit around a remote planet... – nir Aug 3 '15 at 0:00
  • @nir I mean "the set of qualia which are known as 'red." Our sensations are tuned to our experiences. I agree that the sensations constantly change, but choosing to discuss a multi-year study makes it easier to point out something which might be overlooked if I only considered the second-to-second shifts. An individual for whom red is simply "the color of the stop sign" will have a more narrow palette of qualia than that of one who appreciates the subtlest of mixing colors on a canvas by enough of a margin to make a point. – Cort Ammon Aug 3 '15 at 0:07
  • As for the wavelength, I put "not withstanding the qualia of 'redness'" there intentionally, because I agree with you: it is not directly associated with the qualia of redness. However, some choose to argue that "color" is absolute because the frequency of the photons is absolute (or nearly absolute). The shift to discussing photons was simply to cover that, in case it came up. – Cort Ammon Aug 3 '15 at 0:08
  • you write: "An individual for whom red is simply 'the color of the stop sign' will have a more narrow palette of qualia than that of one who appreciates the subtlest of mixing colors". what do you base that on? what is a palette of qualia? one may have a so called richer experience of something after a lot of experience, but that can be explained in terms of memories and associations and knowledge; do you count all these as qualia of red? can you justify that? note that I did not claim that thinking about traffic lights and balloons while watching red has anything to do with the qualia of red – nir Aug 3 '15 at 7:46
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    @nir I base it on a scientific experiment done with colored tiles where people were asked to divide them up into groups by color, which demonstrated just how much power the native language of an individual has on how they approach color in general. It is also based on less scientific online experiments asking people to sort colors into a smooth gradient, and finding some can do it better than others (they "see" more than others). It is also based on my anecdotal experience with learning to appreciate things more, and finding how much fuller they are after I work at it. – Cort Ammon Aug 3 '15 at 14:40

Reinerpost and Cort's posts both make strong points.

I would say that colour is not a universal with respect to either space or time.

Regarding space, the expansion of the universe results in a so called red-shift. This means that light that has originated at great distance as, say blue, will have shifted towards the red end of the spectrum by the time we sense it. Light that has originated as red may have shifted outside of the optical spectrum. Thus, if we could see an apple it a distant galaxy, its reflected light may start out as red, but by the time we see the apple it may appear grey (since the apple has absorbed the other non-red colour frequencies creating a gap in the frequencies being reflected, and the original red light reflected may have shifted outside of the optical spectrum).

The astronomical effect of gravitational lensing also manipulates optical light resulting in colour change.

Regarding time, consider that there is only one form of life on earth. Most animals on earth today have poor colour vision relative to humans. Most animals' colour sense appears to be restricted to greys with a bit of blue and yellow. Some animals "see" ultraviolet frequencies. With this in mind :

Our minds have evolved to create the sensation of red when certain wavelengths of optical light interact with our eyes. Our minds and our eyes will continue to evolve. If we follow our evolutionary chain back, we will witness changes in our colour perception towards those of more lowly evolved animals on earth today and eventually redness would vanish. Similarly, it seems reasonable to assume that our future evolution will also witness changes in our colour perception. So I would say that colour is not universal with respect to time.


It depends on what you mean by "color". Sure, we can measure radiation emitted by objects under various lighting conditions, but what does this tell us about color, exactly?

It depends on your eyes and your language(s).

Color vision varies from person to person (as shown by e.g. various known forms of color blindness); on top of that, color perception is influenced by language and culture (although scientists are debating the details). Not all languages have color names such as ''green'', ''yellow'', ''white'', or ''black''; classical Latin didn't.

  • That sounds bizarre; not that I'm claiming you're wrong, mind you; but how did Romans in the early Roman Empire describe trees, charcoal and their togas?! – Mozibur Ullah Aug 1 '15 at 11:44
  • The point is that (apparently) they did not have pure color names. They had words that described color together with some other quality. So their word for the blackness of charcoal did not purely describe its hue, but also some other aspect of what it looks like. I must say that I only heard this a few times, and e.g. this page appears to contradict it. – reinierpost Aug 1 '15 at 23:31
  • A more important thing is that proper color names (words that describe certain ranges of hues) don't mean the same to eveyone, not even speakers of the same language, not even family members. What is brown to me can be purple to my mother, or vice versa. Sometimes this is a matter of color vision, sometimes a matter of how naming things differently. – reinierpost Aug 1 '15 at 23:37
  • Ok - like crimson, scarlet, vermillion describe red with some other quality. – Mozibur Ullah Aug 2 '15 at 8:49

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