Theory is really much more than learning scales and things...... First of all, I'm not really interested in guitarists.....I'm interested in musicians. My favorite people that play guitar write excellent music, they don't just play guitar. I have come to think that theory is important in writing music. First of all as a means to communicate, since it's one of the main systems of writing and understanding music. Secondly, because it expands what you can do. Maybe some bands that don't know theory just don't go to the point where they won't be able to just "screw around and figure out what sounds good." Things like what Jason Becker does on 'Perspective,' with multi-voice writing and the writing for orchestra. You just can't fake that. That's why, end the end, I like 'BE' better than 'The Human Equation,' to use two recent examples. The Human Equation has some great stuff, but it just doesn't stand out as a whole musical work.....there's not really a general musical idea, it's just songs. And the work is very minimalistic: because Arjen doesn't know any theory, so there are lots of layered synthesizers and sound that is basically the same stuff. On the other hand, 'BE' has more musical continuity, it sticks together. Also, I think the classical instruments are used more to their full potential.....due to knowing really how to use them. So basically this seems to be a major difference between a "guitarist" and a "musician."