All colors exist. Color is not the same as wavelength, color is the human perception of a collection of one or more wavelengths of light. They are all real.

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Waterluvian 6 hours ago | parent [-]

I think this very quickly gets into semantics and then philosophy to the point that it’s not really a useful thing to disagree on.

We can objectively measure the properties of the radiation reaching eyeballs and we can detect sensor differences in some eyeballs in various ways. But we can’t ever know that “red” is the same sensation for both of us.

The concept of “red” is real, made concrete by there being a word for it.

But most colours can be associated with a primary wavelength… except purple. So by that definition, they don’t really exist.

	▲	LegionMammal978 2 hours ago \| parent [-]
		> But most colours can be associated with a primary wavelength… except purple. So by that definition, they don’t really exist. And white, and black. Physically, you'll always have a measurable spectrum of intensities, and some such spectra are typically perceived as "purple". There's no need to pretend that light can only exist in "primary wavelengths". Even if there's no empirical way to extract some 'absolute' mental notion of perceived color, we can get a pretty solid notion of perceived differences in color, from which we can map out models of consensus color perception.