The theories of composition are a foundation to be built upon by the individual. The talented individual can learn them in the beginning and build upon them. The less talented will never move beyond them.
You can give a person the tools needed to succeed, or you can let them figure it out for themselves. Which way will take far longer?
In the future, every time you tell some one to put the books away, I will simply respond with "that is the slowest way to learn, speed up the process by reading the books."
To "color outside the lines" you must first know the lines exist.
Wow...there's one person in this *cough,cough* discussion, who's making some sense. Bitter Jeweler.
Just "looking at pictures" will not teach one the elements and principles of design. One could go to every museum in American and not learn the elements and principles of design. A one-term, college-level course in art history would be a faster path to learning about composition than five years spent looking at pictures. Especially the crap that is being churned out these days and posted by unstudied, talentless hacks on Flickr and Photobucket.
Good Lord...learning about composition and design, well, it's like humankind's understanding of the universe prior to the telescope...we were pretty sure the Earth was flat, and if one went to far out in to the oceans, There Be Dragons Here...
Speaking of giving people the tools to understand things via education as opposed to people learning through the process of osmosis, let's look at a shocking example of how incredibly inefficient untutored, unguided observation is as far as learning about art: It took HUNDREDS of YEARS (millenia, actually) for 'artists' of all abilities to learn how to draw three-dimensional shapes without resorting to a black OUTLINE around all the objects! Europe's finest painters and artists were stuck,hopelessly, with black-outline drawing, for centuries, until art education was invented. Seriously. No exaggeration; the world's foremost, best painters did not even have a clue as to how to paint without using a black border around figures! They also had no clue as to how to draw a vanishing point. So...if one things one will learn composition by just "looking", well, one is desperately wrong. You'll be dead before you learn as much as a second-year art student.