First there is the fact of the Rolling Stones. They’re not just old at this point, they’re really quite old. Like, painful-to-look-at old. You watch them shambling around before the show, greeting dignitaries and dickering about details, creases and canyons in their decrepit faces, and you want to turn away in embarrassment. They don’t just look too old to be playing rock-n-roll, they look too old to leave the house. Then they launch into “Jumping Jack Flash” and, in the space of a guitar riff and a dance move, your embarrassment transmutes into awe. They’re simply flabbergasting to watch. Mick Jagger works harder in any given five minutes on stage than I have in thirty years. And he is propelled forward by Charlie Watts, who works just as hard and receives not half the credit. This band ran out of things to prove about ten thousand shows ago, and yet there they are, still doing it, still blowing away any and all comers. I cannot imagine a performer alive who could watch this band perform and not feel like they had frittered away their life with cautious half-measures. Of performers of their generation still out there, only Bob Dylan has better songs and a comparable list of hits, but he, to my knowledge, has never danced a step in his life and has certainly never succeed in keeping an ensemble of this quality together.

I’m going to come right out and say that the Rolling Stones are, right now, the best they’ve ever been. I don’t know how they pulled that trick off, but that’s what’s happened. Songs that, by all rights, should have been hung out to dry thirty years ago not only sound better than ever, they feel more lived in and more authentic.

“Authenticity”, of course, is the thing that’s haunted the Rolling Stones since the beginning. When they were in their twenties, it was embarrassing to watch them play the blues. They were obviously enthusiasts, but the language of the songs was not theirs — it belonged to another generation. They looked like kids dressing up in their parents’ clothes. Then, as the 60s moved on, they injected more pop and psychedelic elements into their work, and their take on the blues became more ironic, almost a goof. No one believed that Mick Jagger could get no satisfaction, nor could they realistically be expected to believe that he was born in a crossfire hurricane. By augmenting their worship of the blues with a hip, ironic stance (and some pretty damn good songwriting) the Rolling Stones made the blues go pop. In the 70s their sophistication grew to the point where they could meet the blues head-on, fusing pop and the blues into a powerful new form that could include everything from “Brown Sugar” to “Tumbling Dice” to “Angie” to “Beast of Burden.” This era is where the Stones connected with the world and made their mark. As the 80s marched onward, the Stones seemed a little desperate to “keep up,” to remain hip. Maybe it’s just me, but I find it much more embarrassing to watch Mick simper and strut through the 1983 video for “She Was Hot” than to watch any of the moves he pulls in Shine a Light.

(The 80s, it should be noted, beginning as they did with the murder of John Lennon, weren’t good for any 60s act, and the Stones records from that decade hold up better than those of any of their contemporaries, Dirty Work included.)

Anyway, here we are in 2008 and somehow all those layers of irony that the Stones piled on top of the blues have been transformed, through time and experience, into something like authenticity. And in the process of witnessing this, both through decades of listening to the Stones and watching Shine a Light, I find myself questioning the whole idea of authenticity itself.

Take a song like “Far Away Eyes.” This is a goof on country songs, openly disparaging and sarcastic, if lovingly so. I don’t think it would ever become a genuine country hit for anyone, and yet, somehow, over time, its central message, that there is such a thing as a companion whom you can always depend on despite your faults, seems more genuine than it did in 1977. Watching Shine a Light, with a 62-year-old Jagger shouting his way through the song, suddenly the song took on a different meaning for me. Tying together the bleary, worse-for-wear floozy of the chorus with the cynical gospel radio station of the verses, out of nowhere, makes dramatic sense. The narrator prays to the radio station that tells him the Lord is always by his side for a girl who will always be by his side. And perhaps the girl is the Lord, and perhaps the narrator is merely forging the same sex-and-God link that singers (and preachers) have hammered at for a century. Of course, we never find out if the narrator’s prayer is answered — Mick Jagger’s career is, after all, built on unanswered prayers.

Or take “Shine a Light” itself — how could Mick Jagger, ultra cynical, ultra-calculating, jet-set rock star, mean this lyric of humility and redemption? On Exile on Main St., “Shine a Light” feels arch, almost cruel — it’s one thing to make fun of country music, but why pick on gospel? And yet in the context of Shine a Light, “Shine a Light” comes off as, impossibly, genuine and heartfelt. What changed, apart from the singer acquiring the years and wisdom it would take to sing such a lyric?

(Or maybe Scorsese includes the song as a pun — the show, after all, is set at the Beacon Theater.)

So I find myself thinking about the blues and this whole notion of authenticity. Who is to say, at the end of the day, that an ironic goof on the blues form, by a bunch of English guys barely in their thirties, is a less “authentic” presentation of the blues than, say, Robert Johnson?

(Notions of authenticity and authority run throughout Shine a Light, I think intentionally so.  The Stones bring on Jack White, whom I find very authentic if not very authoritative, at least not standing next to Mick Jagger, Buddy Guy, whom I find authoritative but not especially authentic, and Christian Aquilara, who is technically proficient but neither authoritative nor authentic.)

And while we’re on the subject of Robert Johnson, there’s this: I read an article a while back about how Robert Johnson, composer of “Hellhound On My Tail,” did not only sing the blues. There is evidence, the article said, that Johnson preferred to play standards and show tunes in his live sets, but played the blues because, well, that was what was popular at the time.

This takes nothing away from the achievements of Robert Johnson, but the article blew my mind. If Robert Johnson — Robert Johnson — was not sincere, did not “mean it,” was merely performing what the marketplace demanded, was not “authentic,” then who is? And what, then, is the difference between “Stop Breaking Down Blues” and “Honky Tonk Women?” How is one “authentic” and one a cynical goof calculated to exploit the marketplace?

I very much enjoyed seeing the Rolling Stones live a while back, from the other side of a baseball stadium — they didn’t just put on a show, they presented an argument for how life can be lived. But Shine a Light both confirmed my suspicions and shattered (sorry) my preconceptions. The Rolling Stones, somehow, now command the kind of respect and authority they used to confer upon elder bluesmen. The fact that they can accomplish this and remain a stunning, thrilling live act is something indeed.