For that, in two words, is precisely what this protracted one-act concert piece strives to be, and precisely what Christoph Eschenbach and the London Philharmonic strove so valiantly to make it last week. That they, too, failed where others have failed is no reflection on their endeavours. An extra rehearsal or two might well have tightened the ensemble; a more "giving" acoustic than the Royal Festival Hall might well have made more sense of the clotted counterpoint. But Schoenberg's Pelleas is what it is; and what it is is long and dense and obsessive. At any one time, you could be at any one place in the narrative. Of course, even Schoenberg cannot resist visualising Melisande's golden tresses cascading from the tower (four harps mark the spot); likewise our descent into the castle dungeons (cue dank and sinister trombone glissandi).
But, essentially, this is a musical vortex, a web of emotional intrigue. It's expectation without fulfilment, desire without consummation. It seems to shun resolution. There is no good reason for it to end at all.
But it does, and when it does, you wonder why. Perhaps that was the intention. Elusiveness is beautifully conveyed in the crepuscular opening pages: a confluence of bass sonorities so dark that even the cor anglais seems to shed light.
Desire is omnipresent in themes that crave but never find true release. It's all foreplay, this score; you can identify the development, but never feel it.
How strangely cathartic, then, to return after the interval and to discover Schoenberg's enormous orchestra pruned to a quarter of its size. Emanuel Ax played Beethoven's Emperor Concerto with bravura and modesty - big but not ostentatious. He did not stint on the grandiose gestures - his first movement development was steered majestically towards the traditional volley of octaves - nor did he eschew the fantasy inherent in the first movement's crystalline, music-box-like second subject (played with great atmosphere) or the modified rapture of the slow movement which, for once, wasn't made to sound like early Chopin.
Eschenbach (who has sat where Ax was now sitting on so many occasions) was a marvellously alert and purposeful collaborator, leading our ears onwards and upwards towards key modulations, key climaxes, highlighting but not labouring a leading note here, a rising bass line there. He and Ax made the finale's dancing variations anything but flat-footed.
Not yet "the apotheosis of the dance", as Wagner described the Seventh Symphony, but the best of the preliminary rounds.