It's such a magnificent tool for self education:
the Khan Academy!
It's such a great idea: making knowledge and information available,
with videos, made without much extra ado, with simple matter-of-fact explanations, for persons of all ages: a project which is constantly under construction. It's such a helpful tool for everyone, kid or adult, who wants to really learn something that is important to her or him, so that he or she can go on thinking and creating by himself or herself.
It does not answer EVERY question, but many many. And there is always more to come.
Here is a video on the question:
Why Look At Art?
http://www.khanacademy.org/humanities/art-history/introduction-to-art-history/v/why-look-at-art
