Polke died yesterday and, as the old vaudeville line went, how could they tell? How could they tell that an artist so consumed in the transparency of spirit and the lightness of being didn't in fact die, but simply moved to another creative (and created) plane. For this was the essence of Polke, a cosmic joker with a feathery touch, always climbing higher, as on the giant ladder he installed in the Brooklyn show two decades ago.

I remember the day I went, that I was all alone in the gallery and that Polke's work surrounded me like a twilight full of ghosts. Polke was a bit of magpie who saw himself as a visual commentator on the American pop scene. How he loved to poke fun at the severe application of Roy Lichtenstein's Ben-Day dots or optically dense experiments that Robert Rauschenberg conjured up with Billy Klüver.

In turn, Polke influenced other great painters, particularly the glittering optics of Peter Doig and the Maine landscapes which Alex Katz began to produce around the time of Polke's Brooklyn show. There was always something self-abnegating about Polke's wispiest efforts, as if his art and existence was about to go up in smoke. Now it has.