Are art objects products, events under way, or visions? Everything but an answer comes from the conceptually based artists toying with intangibility—with very different physical results—in Now Here Is Also Nowhere. John Divola set his camera on a timer in the middle of the desert, and then ran as far as he could get in 10 seconds, when the lens grabbed and froze him. Jill Magid is selling her cremains to be transformed into a diamond for a ring; the setting is on display with actual legal contracts. Stefan Brüggemann’s big neon piece just says “THIS WORK SHOULD BE TURNED OFF WHEN I DIE.” (Henry Art Gallery, 4100 15th Ave NE, www.henryart.org, 11 am–4 pm, $10 suggested)