When giving this type of explanation, we want to emphasize that the rules are arbitrary and made up because the dominant way of teaching music theory from the 1920s through to the last decade or two has been to claim it as scientifically or mathematically "optimal" in some way. It isn't.
Starting off an explanation of music theory by talking about whole number frequency ratios is like starting off English class with a diagram of the glottis.
Do you feel like the article isn't doing a good enough job getting that lesson across?
> Western music has twelve distinct pitches. This is somewhat arbitrary — twelve has a few nice mathematical properties, but it’s not absolutely necessary. You could create your own set of notes with eleven pitches, or seventeen, or a hundred, or five. There are forms of music elsewhere in the world that do just that.
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> I get the feeling that treating the whole chord/key ecosystem as a set of rules is like studying Renaissance paintings and deciding that’s how art is. It’s not. Do what you want, if it sounds good. I’m gonna go try that. Consensus seems to be that the real heart of music is managing contrast — like every other form of art.
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> Starting off an explanation of music theory by talking about whole number frequency ratios is like starting off English class with a diagram of the glottis.
I would say it's more like starting out an explanation of color theory by talking about wavelengths, even though you don't really need to know any of that to understand composition, and even though most of the rules of image composition are contextual to specific cultures and aren't hard requirements that artists have to obey.
The math behind color is definitely not a requirement that artists should be forced to learn, but some people find it helpful to know what mathematical formulas were used to create a given color wheel.
Starting off an explanation of music theory by talking about whole number frequency ratios is like starting off English class with a diagram of the glottis.