What is a work of art?

What constitutes a work of art?
I don't know. The Whitworth Art Gallery in Manchester England doesn't either - but they try to ask the question better, instead of simply answering it. What interests them is the question of authenticity (and originality) and its place in modern/contemporary art.

Aura and Authenticity is a collection of works that explore the concept of the originality and authorship of art.

The exhibition held at the Whitworth Art Gallery, Manchester until February 2006, raises the issue of the legitimacy of an artwork and the very definition of the genre.

It asks whether a reproduction can maintain the aura of the originals, and whether it is that aura or the perceived value from the fame of the artist which gives the work its value.

Through print, painting, drawing and artefacts, Aura and Authenticity explores the different types of value within a gallery environment, attempting to dispel the myths about what constitutes a work of art.
...

The exhibition is based on the work of the philosopher Walter Benjamin, whose essay The Work of Art in the Age of Mechanical Reproduction, questioned the value system of works of art in the light of new technology. Writing in 1936, he debated whether mechanically reproduced art can have aura even if the artist has never touched it.

(more about the exhibition : at the 24hourmuseum)

I get the impression that when art advances, some concentrate on the questions it left behind. What is the value of this? Maybe it is scarce, but then again, something quite new and surprizing could come out of analyzing Benjamin's interesting, but clearly historical and not contemporary, text and issues.