ART21 is an award-winning series of 24 programmes in which 100 contemporary artists talk about their creations, the way they work and their individual view of art. Might a work of art move us to temper our more destructive impulses? In what ways do artists’ feelings of empathy contribute to works that tackle problematic subjects and address the human condition? The “Art in the Twenty-First Century” documentary “Compassion” explores these questions in the work of the artists William Kentridge, Doris Salcedo, and Carrie Mae Weems.