After nearly a quarter-century as one of its generation’s most daring and defining bands, Animal Collective remains committed to the beginner’s mind. The bands structure has long been that of a playground, an open space for exercising and indulging new notions and influences, for saying “Why not?” from way up on the high beams. Maybe that means allowing Panda Bear to focus on his drumming more or encouraging Deakin to dig more deeply into his piano playing. Or perhaps it is giving Avey Tare and Geologist’s burgeoning interest in Renaissance music—plainchant, the hurdy-gurdy, gilded polyphony—space to bloom. Those impulses are at the very core of Isn’t It Now?, the second Animal Collective album in as many years and a striking landmark on their joyously circuitous journey.