Art: Honest Prophet

At 69, Mark Tobey is the oldest living prophet of abstract expressionism, but Tobey opposes isms in general, and remains chronically unsure of what he himself is doing. Yet last year he took the Grand Prize at the Venice biennial, the first American painter so honored since James McNeill Whistler. And last week a major Tobey retrospective show, mounted by the Seattle Art Museum, was delighting Portland, Ore. on the second lap of a tour that will include Colorado Springs, Pasadena and San Francisco. Leaning on the piano in his drab Seattle...