>>11774067From an individual perspective, the separation of colors is objective: it is not your opinion that red and green are distinct entities; that's just the way it is. You can still argue that this is subjective in the same sense that reading the measurement of a ruler is subjective, but this is as close to objective as we are going to get.
Problems arise when you need to communicate what you see to other people. The problem with expressing color in words is that you need to decide on a definition. This is done by a sort of data feeding. You get another person and you point out objects and say: that's red, that's not red, that's red, that's not red...and hopefully after enough examples you chisel out in the mind of the other person mind what you mean by red. This approximation, this collective understanding, your personal understanding of the word red is subjective.
Now, just because it is subjective, that doesn't mean it is arbitrary. It is systematic; it is based on how a 'typical' human being perceives color. The scientific question is what are we really perceiving (the underlying physical reality to the extent that there is one) when we talk about color. Answering this question bridges the gap of language and our personal observations. We can use tautology: Light with x characteristics is perceived as red; therefore, red is light with x characteristics. This isn't undeniably objective; it is just strong correlation, but you can say that to the extent that we can know anything, we can know red has those characteristics.
We see a lot more than we actually communicate to other people. Our color vocabulary is limited by utilitarian purposes of what we want to communicate to other people. You can call this arbitrary and insist we change it, but if you try to make me memorize a 100 different color names I'm through!
