Breaking the Rules

In chapter seven of Levitin, I found it interesting that he talks about expert musicians who never learned how to play music in the traditional way.  For example, Joni Mitchell never took guitar lessons, but she is considered an expert at what she does.  Not only that, but she has approached music making from a very unique perspective and has done innovative things with chords.  Her lack of training is what gave her such an unconventional way of playing.  If she had taken guitar lessons and learned all the rules, she would have never thought to break them.  But it's not as if she way trying to "break the rules" of music; she didn't know them to begin with.

It has been stated in class that you have to know the rules in order to break them.  You have to be an expert at what you're doing before you start experimenting.  I'm not sure if I agree with that.  Joni Mitchell was breaking the rules without even knowing what they were.  Having rules for music, or any other art form, limits people's creativity.  In a way, Joni Mitchell was lucky to have never been taught the rules.  It made it easier for her to do be innovative.  That being said, there are benefits to having rules in music.  It makes it easier to organize and teach others.  My question is  is it better to be taught how to play an instrument by an expert, or to learn on your own?