How to Make Guitar Sound Like Music

The score had to be procedural, generate from little bits and pieces that you could assemble on the fly in lots of different ways. But it had to sound natural to it, had to sound organic. He wanted it based on finger style guitar. Some other instruments, some other colors could be brought in. There were like six or seven key objectives that we had. And as I went home from that, those days of brainstorming, I thought, all of this is easy except for one thing. How do you actually make it sound like music?