Mark Morris’s “The Look of Love” begins with praise. Dancers stand in a circle facing inward with clasped hands and chests lifted as Burt Bacharach’s “What the World Needs Now” resonates in the theatre. Morris’s dance, which was first performed in 2022 and had its New York premiere at the Brooklyn Academy of Music on March 20th, is a celebration of Bacharach’s music and his idea of love, which, in spite of minor ups and downs, remains, as the opening song suggests, overwhelmingly “sweet.”