Believing that music can change the world. It seems almost quaint now, in this age of all but countless festivals, from Bonaroo to Bethel and back again. But 40 years ago, when a few rather idealistic beatniks conceived of a three-day celebration with a soundtrack of the era's finest musicians and songwriters, they were exploring uncharted territory.

Woodstock paved the way for what we now understand to be a de rigueur part of the summer concert season.

But it did so much more. Woodstock presented us with a mythology that has framed rock music ever since.

Making the world safe for long, often muddy, even more often financially exploitative, and invariably pungent (in one way or another) rock festivals might be a dubious achievement. One could argue that a four-hour show in a more intimate environ with a band or two you really care about -- not to mention easier access to cold beer and running water -- beats rolling around in the mud on some air force base allotment or cow pasture, hands down.

Woodstock did create the paradigm for everything from the California Jam fests of the '70s, to Live Aid in the '80s, to traveling road shows like Lollapalooza and Ozzfest, which became don't-miss events in the '90s.

It also signaled an end to the idealistic, community-based essence of '60s rock music. After Woodstock, rock was big business, not an underground convergence of the like-minded. The festival managed to simultaneously encapsulate all that was good about the subculture of the '60s, and sound its death-knell as an underground movement.

What blossomed almost immediately following the event, however, has endured. At its core, this mythology is the belief that the music itself can be transformative; that actively engaging in creating it and listening to it can teach us to live more fully in the moment. By extension, those who have been altered somehow by immersion in the music can then go out and effect change in the world.

It's the willful embracing of that mythology - one that proved to be naive, deeply flawed, hopelessly Utopian - that has been the impetus for most of the great music that has been made since.

So how does believing in something that seems wholly impossible and counter to logic become a brave and artistically empowering act?

Woodstock, as cliche-ridden and posture-bound as has been the scholarship surrounding the event over the past 40 years, still provides the answer. It was a crazy idea that almost made sense, a pipe dream that stumbled into reality like a newborn, basked in the brief glow, and then passed out in the mud.

But it was enough. The window was now open.

The popular spin on Woodstock suggests that it was all flowers, hand-holding, LSD and skinny-dipping. Maybe it was, for a large portion of the crowd. The best reporting on Woodstock, however, isn't really reportorial at all. It takes the form of a poem, penned by a songwriter who wasn't at the concert itself.

Joni Mitchell wrote the song "Woodstock" as the festival was taking place, after being ditched at the airport by her traveling companions, Crosby Stills & Nash. She watched the whole thing unfold on television, but somehow managed to capture the romantic mythology that had midwived the festival's birth.

Remarkably, Mitchell's song - which became a big hit in a radically restructured form for CS&N - came across as both world-weary and jubilant, as if she knew that the very concepts she was conjuring would not survive the grim realities of morning.

"We are stardust/ Billion year old carbon/ We are golden/ Caught in the devil's bargain/And we've got to get ourselves back to the garden," runs the refrain of the prayerlike tune, and though these words have been deemed the nadir of hippie-dippy idealism in the years since, they are the opposite.

Mitchell saw the festival in biblical terms, as indicative of fallen man's yearning to return to the Garden of Eden. It wasn't about a bunch of rock bands playing for a mostly wasted tribe of hippies in a mud pit. It was about a generation attempting to reclaim its birthright, to, in Mitchell's words, "lose the smog" and the feeling of being "a cog in something turning." It was about grabbing the concept of freedom by the scruff of the neck and throwing it around, to see what it was made of.

Far from the naive optimism so often associated with Woodstock reminiscence, Mitchell's song is presented as a dream, but it's a dream that knows it's not likely to make the leap from sleep into reality once the dreamer wakes up. This is what gives the song its power and resonance. It's also the true legacy of Woodstock, this willful belief that the marriage of music and thought and compassion might turn "bombers riding shotgun in the sky" into "butterflies above our nation."

Well, no, it can't. And yes, it can.

It really doesn't matter if you were at Woodstock, or elsewhere, or perhaps not even born yet. The wave crested, and then it rolled back, leaving a generation's hopes washed up on the beach. There they sit, waiting to be picked through, used as raw materials in the construction of new dreams.

Maybe the concept of "hippie" is anathema to you. Maybe you simply see rock festivals as gross capitalism run amok, or a simple excuse for people to gather, party, and forget themselves for a while. Perhaps you feel that glorifying and honoring the past to the degree that Woodstock - and the acts associated with it - has been over the past 40 years means that we overlook the best that the present has to offer in the process.

Regardless, Mitchell's poem applies to you when it hits its emotional peak with these words: "I don't know who I am/But life is for learning."

Those words, and the approach to life that informs them, still glitter and gleam in the sun, 40 years on.