“To me, to write a symphony is to build a world using all the means of available technique,” wrote Gustav Mahler. Nowhere does he implement this credo more overwhelming than in his “Symphony of a Thousand.” With eight soloists, three choirs, and a colossal orchestra, he pushes beyond all that came before. Yet, Mahler not only unleashes an immense torrent of sound; he also distils fundamental thoughts from the history of philosophy – from the medieval hymn to the conclusion of Goethe’s Faust. After 15 years, the Berliner Philharmoniker brings this spectacular work back to the stage. Kirill Petrenko conducts.