Is Roy G. Biv a Real Person?

In school we learned in both science and art classes that light filtered through a prism is divided into 7 colors, namely: red, orange, yellow, green, blue, indigo and violet. We memorized the Roy G. Biv mantra in order to remember it for the test. And, still, I ask: isn't indigo a shade of blue? I am now realizing how subjective seeing really is. We really do understand that the list of possible colors in infinite. Designers invent and reinvent new colors all the time to keep us buying; i.e. sage, eggplant and butterscotch. Naming and naming. Dividing and further dividing. Yet, in college sociology class, I learned of a primitive tribe that had only two naming words for color. Of course, I cannot recall the exact words, but I would guess that they might have meant warm-ish and cool-ish. Red, orange and yellow are warmish. Blue, indigo and violet are coolish. Green is a swing middle-initial. Even though all hues can be altered to a warm end or a cool end, each has its innate temperature property. I love simplification. And often, I think that the color temperature notion is a better way to approach a painting....that way we don't get caught up in all of those divisions. I think that we should be able to declare either warm-dominance or cool-dominance before we begin....that depending on the subject matter. Dominance is important for harmony and is a key design principle. Using like amounts of warms and cools results in a static feeling...not near as visually interesting! (a clear case for assymmetry of all kinds).