the parallel is divisibility by 2. re: what determines what sounds good, in some sense you can read up on music theory for this (scales / keys). in a more bas

the parallel is divisibility by 2. re: what determines what sounds good, in some sense you can read up on music theory for this (scales / keys). in a more basic sense ("why is this sad and this happy?") it's actually an open and actively researched question in the physics of music. it's anyone's guess, really, why certain melodies are pleasant. is it a physical/structural/formal feature of the sound itself? is it a feature of our psychology or neurological makeup? who knows.