I acknowledge that what we perceive electromagnetic waves of frequency 400 micro meters as green because that's what we decided to call green and not the other way around. But by our experience of colors, qualia, I don't mean physical or biological correlates of color, but the pure "greeness" of green, the pure quale of green you imagine when you hear the word.

On the other hand, our private experience of colors isn't just random and disconnected from this world. So for instance they come in order given by their frequencies, apparently regardless of the characteristics of our experience of those colors. Or is there some kind of order in the color qualia?

Is there any connection between the color frequencies and the qualia we connect to them? What do we know about the characteristics of our color qualia at all?

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    This question is answerable by cognitive science and biology. We've also had variations on this question several times here. Wikipedia can tell you what colors the cones in your eyes see (en.wikipedia.org/wiki/Cone_cell) . – virmaior Dec 20 '16 at 7:55
  • If this is the question I am thinking of, it's a response to a closed ticket on the Physics.SE. On the Physics.SE it was clear that the OP was not looking for a scientific answer. They truly wanted some concept of an order of the qualia of the colors, which could only be a philosophical question. – Cort Ammon Dec 21 '16 at 3:46
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    I do not believe that physics, cognitive science or biology study "qualia". If this question is indeed a duplicate then it should be marked as such, but looking at the list on the right I don't really see a suitable original. What I find interesting is that people often confuse "qualia" with independent relational properties, and most of the qualia talk relies on the latter, color space is a vivid example. Indeed Jackson's "knowledge argument" assumes that relational properties of color are derived from qualia. – Conifold Dec 24 '16 at 2:26
  • @Conifold Yes, that's exactly what I've been thinking about it! – Probably Dec 24 '16 at 8:08

If by "experience" you just mean qualia then the "connection" is purely accidental. We do not need to compare qualia to agree to call the same objects "green", nor do we need it to associate them to certain frequencies or spectra. We can equally well agree on outputs of optical spectrometers without that. By the way, most colors are not associated to a single frequency, they are combinations of monochromatic waves with a spectrum of frequencies, but mostly well approximated by weighted sums of the "primary colors", RGB, to which our retinal cones are specifically attuned (at least on the traditional trichromatic theory, it is contested). There are some more subtle things that we can compare, like whether or not we agree that some shade of blue is "between" the other two, this is how shades are correlated to spectra more specifically and the psychological color space is mapped out, see Bimler's Psychological Color Space and Color Terms. But this is still relational information about arranging the shades relative to each other, it conveys nothing about what the shades "feel like".

In fact, it is unclear if "knowing" someone else's qualia is a meaningful idea, and hence if the question of having the "same" or "different" qualia makes sense at all. You can not see my qualia because for that you'd have to become me and then "you" won't be seeing them, and if they somehow become "yours" they will no longer be "mine". Such are the rules of qualia. We might speculate about some "common nature" of the human race, which ensures that our qualia "truly are" the same. But again, the question is not even whether this is true, but what possible sense it can make.

And we do know that the supposed "common nature" is not that common. Indeed, we can attach some meaning to "seeing colors differently" because different people differ on color even relationally, e.g. color blind people do not distinguish shades that the majority does. Dalton describes his color blindness as follows, see Is it possible that I see color differently?

"That part of the image which others call red appears to me little more than a shade or defect of light. After that the orange, yellow and green seem one color which descends pretty uniformly from an intense to a rare yellow, making what I should call different shades of yellow”.

This should not be surprising. As Poincare observed in The Value of Science, science, being objective (by which he meant intersubjective, communicable), can study nothing about "qualities" of things in themselves, only about relations among them:

"Sensations are therefore intransmissible, or rather all that is pure quality in them is intransmissible and forever impenetrable. But it is not the same with relations between these sensations. From this point of view, all that is objective is devoid of all quality and is only pure relation... we must nevertheless admit that nothing is objective which is not transmissible, and consequently that the relations between the sensations can alone have an objective value."

Eventually this position evolved into structural realism, the most popular kind of realism today, see Brading's Epistemic Structural Realism and Poincare's Philosophy of Science. Many dispute that even relations (or relations among relations) are communicable due to indeterminacy of translation and other reasons. But qualia are the first to go, and at best the frequencies reflect relations among qualia only.

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    "you can not see my qualia because for that you'd have to become me and then "you" won't be seeing them, and if they somehow become "yours" they will no longer be "mine"" That's just counts with the assumption that we will be never able to study qualia. – Probably Dec 20 '16 at 21:39
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    @Probably It is more like the definition of qualia ensures that there is nothing there to study, whatever is studiable will not be qualia. As Wittgenstein pointed out, not only can we not compare our qualia to somebody else's, we can not even compare our own at different points in time. If we say they are the same they are the same, there is no independent way to tell, hence to be right or wrong about it. – Conifold Dec 20 '16 at 22:20

The wavelength of light can, of course, be measured and compared, but the phenomenal qualities of color must be distinguished from its physical properties. In his classic text, Physics, The Elements, Norman Robert Campbell investigates the nature of measurement in some depth, proposing the following criteria for measurable quantities:

"The relation generating order. But order may also arise, not from an arbitrary convention, but from real properties of the things ordered; and it is of course the existence of this real order which has led to the invention of arbitrary orders to denote the things characterised by it. Such real order is possessed by the houses in a street and by Numbers, and by many of the other objects which are usually denoted by numerals. Now this real order, as pure mathematicians inform us, arises from certain relations obtaining between the things which are ordered, namely, such relations as are technically called 'transitive and asymmetrical'." (N. R. Campbell, Physics, The Elements, p.268)

He goes on to specifically assert that color is not a measurable quantity:

"Colour cannot be measured. We cannot apply the same process to colour because we cannot find a similar transitive and asymmetrical relation which expresses differences of colour and covers the whole range of coloured bodies. 'Different in colour' is, as we have noted, symmetrical but not always intransitive; 'redder than', 'darker than' are intransitive and symmetrical relations, but they do not cover the whole field. Some colours are neither redder nor less red than others, two shades of the same blue, for example; and yet they are not 'equal in colour', as the two bodies which would neither scratch nor be scratched by each other were equal in hardness. For they are not similarly related to all other coloured bodies; one may be darker and the other lighter than some third colour. Accordingly we cannot range them in a single series characterised by a definite order, even if we have recourse to the device of allowing the same place in the series to be occupied by several terms. There is no natural order of the colours which enables us to denote them by the series of numerals except by the most arbitrary convention." (N. R. Campbell, Physics, The Elements, p.272)

To specifically answer your question, there is no known direct relation between frequency and qualia. We only know their characteristics by our experience, and since there is no way to directly interact with phenomenal qualities, they remain out of our reach for further analysis.

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