Ah, I left these long draw-out discussions in my last Art History class so I'll just throw in two simple quotes that SPEAK OF art, because you can't FULLY and ACCURATELY define something so profound, intricate, and complex with one catchy phrase, however meaningful, or with a couple of paragraphs on an internet forum:

What was any art but a mould in which to imprison for a moment the shining elusive element which is life itself - life hurrying past us and running away, too strong to stop, too sweet to lose.
- Willa Cather

The aim of art is to represent not the outward appearance of things, but their inward significance.
- Aristotle