Art: it's this visual record of who we are, how we imagine ourselves, where we're going, where we've come from. It's the visual record of out psychological states - as a human organism. If you were to take all the varied pieces of art from all the different art movements in some brief span of time, you'd find a wide spectrum of emotions, perspectives, and inspirations. Yet, it all came from the same place - this Earth - and happened at the same time.
The things we consider valuable on this planet - the things which have attained a greater sense of value than, say, food or water - are valued simply because they are perceived to have valuable. For instance, a gold bar is perceived to have a certain value. One gold bar can be melted down and turned into another. Cast it as a sculpture by Dali and it now has a greater perceived value. It has been turned into Art. It is that expression which creates new value.