I heard as good an answer (for me) to this question while listening to an Arts radio program on ABC radio this morning: "The purpose of Art is to enhance our understanding of the world we live in".
Then I found myself thinking: What artworks HAD enhanced my understanding of the world? I'm still thinking about this, but certain works of painting, writing, music, drama & film started popping into my head.
For example, Bob Dylan's music & lyrics, when I first heard them, certainly changed my perceptions, political understanding & attitude to music. No turning back after that!
As a secondary school student my discovery of the paintings of Monet, Degas, Manet, etc. changed my perceptions of what was "good" Art, which was a suitable subject for a painting & taught me to love brush strokes (!)
There are many, many more examples of books, films, poems, paintings & sculptures that come to mind. But I'd love to hear YOUR thoughts on this:
Do you agree with this definition of Art's purpose? If not, what's your definition?
And which particular works did, in fact change your perceptions?