Dwan Gallery donated “Double Negative” to the Museum of Contemporary Art, in Los Angeles, in the eighties, and Heizer hasn’t visited it for years. The degradation there depresses him: its clean, deep cuts have filled with boulders calved from the sides. Though he originally intended the piece to respond to time and ultimately be reclaimed by geologic processes, at some point he changed his mind, and now hopes to find the money to restore it. Govan thinks that this reversal came partly because Smithson championed the principle of entropy, and Heizer wanted nothing to do…