When the literary symposium about Brandeis University’s Rose Art Museum takes place March 16, participants might consider the museum’s modest attendance figures. “We have become so accustomed to using pop-culture yardsticks — profitability, celebrity, fashion — to measure the success or failure of art and art museums that it’s easy to lose sight of what matters. In fact, a degree of obscurity, relatively speaking, is one of the great charms of the Rose’s collection.”