The Barnes Collection outside Philadelphia is a great museum yes. But it’s also an extraordinary art school. “There probably isn’t another art school, anywhere, in which students are immersed week after week in one of the world’s great collections. They sit on folding metal chairs in the foundation’s galleries as the instructors teach from celebrated paintings by Renoir, Matisse, Cézanne, Picasso, and dozens of other modern masters. It’s hard to overstate the value of such exposure.”