The difference between rules in programming and rules in music is that in the first case they're normative, in the second case they're descriptive.
Music theory can tell you why a specific combination of notes and a chord progression in a musical piece are pleasant to the ear, but does not guarantee that using similar combinations and progressions will result in pleasant sounds.
Part of the reason is subjectivity, in the sense of music is intended to be heard by subjects. And these subjects have their own experiences of music, which in turn conditions their expectations and their reactions to sounds. What sounds good is different from person to person, let alone from culture to culture. Coming from a classical background, when I heard jazz at a young age, I considered it chaotic and awful. Today, it's the most pleasant style of music for my ears. I've seen people who had never, ever heard opera music listen to an aria and laugh to tears because for them it was comically awful.
Another is reason, I think, is that music is embodied by who plays it. I can play Blackbird in the exact same way Paul McCartney does, but when I do it the best I can expect is people saying "that's nice!". When McCartney plays it, the entire stadium hold their breath and get chills, some are in tears. I don't see how that level of emotion can be explained in a scientific way.
Music theory can tell you why a specific combination of notes and a chord progression in a musical piece are pleasant to the ear, but does not guarantee that using similar combinations and progressions will result in pleasant sounds.
Part of the reason is subjectivity, in the sense of music is intended to be heard by subjects. And these subjects have their own experiences of music, which in turn conditions their expectations and their reactions to sounds. What sounds good is different from person to person, let alone from culture to culture. Coming from a classical background, when I heard jazz at a young age, I considered it chaotic and awful. Today, it's the most pleasant style of music for my ears. I've seen people who had never, ever heard opera music listen to an aria and laugh to tears because for them it was comically awful.
Another is reason, I think, is that music is embodied by who plays it. I can play Blackbird in the exact same way Paul McCartney does, but when I do it the best I can expect is people saying "that's nice!". When McCartney plays it, the entire stadium hold their breath and get chills, some are in tears. I don't see how that level of emotion can be explained in a scientific way.