There are many, many art worlds. Art contains multitudes.

'Untitled' is a time machine that can transport you to 1992, an edgy moment when the art world was crumbling, money was scarce, and artists like Tiravanija were in the nascent stages of combining Happenings, performance art, John Cage, Joseph Beuys, and the do-it-yourself ethos of punk. Meanwhile, a new art world was coming into being.

Billions of photos are shot every year, and about the toughest thing a photographer can do is invent an original, deeply personal, instantly recognizable visual style. In the early nineties, Wolfgang Tillmans did just that, transforming himself into a new kind of artist-photographer of modern life.

I think that a lot of artists have succeeded in making what I might call "curator's art." Everybody's being accepted, and I always want to say, "Really? That's what you've come for? To make art that looks a lot like somebody else's art?" If I am thinking of somebody else's art in front of your art, that's a problem.

First let me report that the art in the Barnes Collection has never looked better. My trips to the old Barnes were always amazing, but except on the sunniest days, you could barely see the art. The building always felt pushed beyond its capacity.

The art world is molting - some would say melting. Galleries are closing; museums are scaling back.

I just want to say one thing about the '70s. Enough with this purer, "It was a better time," business. Every time is about as polluted and needy and beautiful as most other times. I was around in the '70s, and people were just as ambitious and envious and filled with need and desire as they are today.