Color theory is a wide subject. The context it was used in this discussion was for design and the influence of colors on the end user for things like UX, branding, etc. Yes, color theory also includes important and technical things like color spaces and human perception but that's not what we were discussing here.

To quote the OP: "How different colors mean different things (Branding-wise or for alerts/errors/warning)"

And, maybe I am wrong about this, but it seems like you've never even heard of color psychology since you seem to think that it's completely unrelated to color theory and that it's a strawman I cooked up out of nowhere. It's even linked in the related section on the wikipage for color theory https://en.wikipedia.org/wiki/Color_psychology

> Color theory makes no subjective judgements on what colors "mean" or should be used for, but instead focuses on the visual properties and perception of color.

The parent was talking about color harmony (color wheels) and color psychology. This are very much the things the Wikipedia article you linked is about.

Both are indeed pseudo-scientific mumbo-jumbo.

I'm also doubtful about color psychology, but color model theory (including color wheels) has some real substance. Most web sites from the late 1990s are today recognized as ugly because the color choices were awful (perhaps because they were trying to be compatible with graphics cards that only allowed 8 bits per pixel.) Web sites with colors that fit a recognized color model appeal to a lot more people.

Color model theory is similar to music theory, in the sense that both theories may just be a codification of familiar patterns. That doesn't mean they're not useful.

> Color model theory is similar to music theory, in the sense that both theories may just be a codification of familiar patterns. That doesn't mean they're not useful.

Color harmony might well be just a codification of familiar patterns. Musical harmony on the other hand is very different. While it certainly has some parts that are rooted in familiarity, especially when it comes to consonance and dissonance of certain intervalls, most of it has a strong physical and physiological basis.

Musical harmony is not purely subjective and this is well studied. Color harmony is not well studied at all and if there is and serious basis - except for historical use - has yet to be been. That’s why I don’t like the word harmony in connection with colors. It just gives the wrong impression.

They said music theory, not music harmony. Music harmony is a subset of music theory and music theory is a codification of familiar patterns. Those patterns likely formed because of their strong physical/physiological effects.

I don't know enough about the visual arts to know whether color harmony is a subset of color theory. Or if color harmony is even a thing.