The Ars Nova season opens with Made Perfect, a one-hour program centered around Giovanni Pierluigi da Palestrina’s otherwordly Missa Brevis, flanked by several of Palestrina’s motets and the late British composer John Tavener’s For the Fallen (drawn from his Exhortation and Kohima). Both Palestrina’s towering, yet deeply intimate, Brevis and Tavener’s Fallen give voice to the kind of shared grief many are feeling these days, and the desire to make order out of chaos.