Another nice thing about 12 notes is that 12 has lots of factors. It leads to a lot of cool symmetries which I think have to do with how we understand music. F

Another nice thing about 12 notes is that 12 has lots of factors. It leads to a lot of cool symmetries which I think have to do with how we understand music. For example, since 12 is divisible by 3 and 4, diminished chords (4 notes separated by intervals of 3) and augmented chords (3 by 4) don’t have a definitive centre to our ear. As a result they both create different flavours of uncertainty and suspense. But if you break the symmetry, e.g. by moving any note in an augmented chord one to the left on a piano, the chord takes on a colour (in this case becomes a major chord). Other equal temperament scales would end up having similar patterns, but at the cost of complexity. having closer to 20 or 30 notes in an octave would increase the number of patterns to recognize, and probably make them less distinct to us without practice. It’s also interesting to me that we put 12 numbers on clocks as well.