Elliott Carter's ''Symphonia: Sum fluxae pretium spei" (the Latin means ''I am the prize of flowing hope") is the toughest nut that James Levine is giving the Boston Symphony Orchestra and its public to crack this season. But his belief in the piece is absolute. In his note to the audience in the program book, Levine writes of an ''imagination, physical energy, and reflection" that Carter shares with Beethoven.
Symphony Hall wasn't quite full, but the audience listened attentively and gave the 95-year-old composer a standing ovation when he appeared onstage. Touchingly, Carter, looking animated, hung his cane on Levine's music stand so he could join conductor and audience in applauding the orchestra.
''Symphonia" is a long work, 45 minutes, and Levine preceded it with the little fantasy, ''Micomicon," that Carter composed for the BSO as kind of introduction to the piece last season. The three movements are of strongly contrasting character, and each is more immediately accessible than the last. One way in to listening is through the poem ''Bulla" (''Bubble") by the English poet Richard Crashaw, in which the speaker invokes a bubble and what it sees, what it reflects; toward the end the bubble speaks, and Carter invites the listener to reflect on those particular lines in each of the movements.
The first movement is about the contradictory complexity of human experience. The second is a kind of funeral march (like the second movement of Beethoven's ''Eroica" on the second half of the program); it is full of tragic grief and personal pain, and the sound of muted trumpets suggests a bloodstained battlefield. The third movement is quicksilver enchantment, even bubblicious.
The piece as a whole is a symphony of solos -- of individual instruments, of sections of the orchestra, of combinations of instruments. One way to listen is to follow some of those solos, then hear how none stands alone; other solos are going on at the same time, almost always of contrasting character.
There is a good recording of the piece, but what it cannot convey is the spatiality of the music, how it plays out across the orchestra and into the hall. And the recording cannot convey the intensity with which the BSO played, or the sheer physical beauty of most of the sounds in the piece, from the opening flourish, with a bit of boogie in the bass, to the final, high, poised G-sharp from the piccolo, beautifully intoned by Linda Toote. Last night's was only the third complete public performance of the ''Symphonia," and it will be a long time before conductors, players, and audiences fully assimilate the work, but what we heard was already astonishing, and it fulfilled its first duty, to make you want to hear it again.
Levine led a noble ''Funeral March" in the ''Eroica," the shift from minor to major like a shaft of light. Much of the rest of it combined attention to detail with an almost reckless abandon, sometimes at the cost of tonal luster; Levine made this symphony sound new and urgent again.