IN A PHOTOGRAPH from Louise Lawler’s recent exhibition at Sprüth Magers, Los Angeles, the sculpted head of a horse appears doubled. The long-exposure shot, captured as the artist made a swiping motion with the camera, depicts a plaster cast of a statue, once part of the east pediment of the Parthenon, splitting into a pair of heads a blurred white form, a still-blurrier ghost. They seem to fly across a black void, conforming to the Iliadic formula of “swift-footed steeds,” but also seeming to refer to nothing except themselves.