(Similarly, "brain" and "mind" are not the same.)
Otherwise, the intended general idea is that found e.g. at the beginning of Arthur Schopenhauer's Welt als Wille und Vorstellung:
> "The world is my representation": this holds true for every living, cognitive being, although only a human being can bring it to abstract, reflective consciousness: and if he actually does so he has become philosophically sound
What do you mean? (Outside the detail that "hues" are electromagnetic frequencies, while colours are compositions - there I just simplified.) Which colour is not such?
They aren't. For example, put a card of color A in front of a background of color B; now move it in front of a different background of color C. You will experience color A as being a different color (especially if colors A, B, and C are chosen to maximze the effect).
The electromagnetic spectrum returned by card A isn't different, but the color perceived is. Thus, electromagnetic spectrum is "out there", but color is "in here".
Oh, nobody said they overlap.
The original post claimed that «Colors don't exist outside of your brain»: such statement, while true, is false, as its negation is true (we have mentioned paraconsistency in this very page): "colours" do exist outside your brain, as their nature also is, in a way, being electromagnetic phenomena, function of frequencies.
While such ontological property is pretty common, it is just summoned with some force when someone claims "[fuzzy] is [strict]".
> Thus, electromagnetic spectrum is "out there", but color is "in here"
Of course. That just depends on what you want colour to be. If you put it conceptually near "electromagnetic spectrum", then the distinction emerges.
For that matter, not even "pinkish grey" is defined by simply a frequency (the hue is, the colour is not): the definition for this purpose was meant to be concise, not literal.
That was not the point, and said counterexample is not such (also magenta is, in a way, "electromagnetic frequenc[ies]"). Impossible colours - virtual colours - do go more towards the counterexample, though up to a certain point as they refer to the mental phenomenon of colour and leave the physical nature of colour untouched.
But finally I get what you meant when you stated: «not all colors are electromagnetic frequencies». True ("not all perception is produced by a direct influx of"). But also false, apparently (to the best of my), as objectivized hybrid colours are compositions of electromagnetic ranges; objectivized virtual colours are as well etc.
> Color is a complex phenomenon that cannot be reduced to electromagnetic frequencies and their composition
Yes, and nobody ever stated the opposite - no reduction was never implied, no «overlapping» (as written in the other post): the point was expressed, nearby, at https://news.ycombinator.com/item?id=31217999