Ha ha. Get it? He (Laurent Le Bon, director of the Centre Pompidou-Metz) has to avoid tripping over his own concept. You can't have a "definitive definition" that is about diversity and contradictions. If you're into diversity and contradictions, how can you answer any of the questions that are asked?
And... "definitive definition" — isn't that a funny term? It should be a redundancy. If it's a definition at all, it should necessarily be definitive. If he can't give a definitive definition, he's not giving a definition at all, one would think. He's eschewing definition. He wants people to give diverse and contradictory meanings to the term used to name the show at his museum.
So... do you care what works of art get labeled "masterpiece"? If so, why and what would you put the label on?