This year marks the 80th birthday of American artist Bruce Nauman. Following on from a recent Tate retrospective is Presence/Absence at White Cube, the first exhibition in Hong Kong for the pioneering video artist, featuring five works: two single-channel pieces, from 1999 and 2001; and three dual-screen projections made in 2013. The artist is present in all but one of them. Many of Nauman’s earlier works are about time and endurance: his own as an artist, as he pushes himself to physical limits; and the audience’s, as they try to sit through videos of maniacal clowns (Clown Torture, 1987), and of the artist performing mundane tasks. In one of several early videos from 1968, we see him bouncing off the wall (Bouncing in the Corner I), making the viewer dizzy in the process. In another, Walk with Contrapposto (1968), he walks back and forth in a narrow corridor, exaggeratedly swinging his hips side to side. Similarly, in Walking in an Exaggerated Manner Around the Perimeter of a Square (1968), he places one foot in front …