Art: A Sense of Exuberance

It has been a year for gimmicks and theory-clogged trivia in many fashionable art galleries, so one can only rejoice at a show that demonstrates anew the richness and ethical seriousness of painting. Such an exhibition—modest in scale, exceptional in quality—is now on view at the Walker Art Center in Minneapolis: a group of 16 new pictures by Robert Motherwell.

To speak of a "comeback" by an artist as conspicuous as Motherwell may seem odd, but it has a certain point. At 57, he is one of the last charter members of the New...