Sitting in a coffee shop I heard a man say, "I saw Black Swan the other night. It was trash. Elevated trash, but trash." "Black Swan was great," you say to yourself and aloud.

When you see a good movie, a very good movie, it's difficult to remember that the film is not objectively extraordinary.

You are certain the world agrees. Summer is hot, winter is cold, and Black Swan is a great film. Now this isn't exactly evidence you are feeling superior. Superiority means knowing there exists another lesser point of view over which yours rises supreme. If you cannot even fathom an opposing view it is beyond arrogance. It is pure solipsism.

So, if you are sitting in a coffee shop and you hear a man say:

"I mean it was just awful. Natalie Portman was sweating beads, and blood and just really straining for an Oscar. I don't like it when actors strain. When you have to strain to do it, when it's not natural, it's just fake to me."

The world will crack in two.

Of course this thinking reveals that I am often deep in my own world with its own rules and definitions for things.

Which brings us neatly to the issue of Nina and her many identities, a split shown most clearly in the bathroom: the Western world's last vestige of privacy in an increasingly transparent society.

For those of us not living or working in solitude, the bathroom offers the sole moments in our day when we may escape the gaze of others.

For Nina, trapped under the eyes of her mother and fellow ballerinas, bathroom moments are essential. She has grown to adulthood without ever having true privacy. It is only when Nina is given a private dressing room, the first room in her life that is truly respected as hers, that her rival identity emerges. This is the darker Nina that then bars her bathroom and bedroom door. This is the Nina that emerges only when given solitude.

When Nina does not have her dressing room, she has the bathroom.

If we aren't in an emotional crisis, these few minutes aren't usually regarded as significant, but any time spent away from other eyes, even seconds, is important. These moments demonstrate to us not only the rapidity with which we can switch modes but the sharp differences between our various public personas and our many private selves.

Think of all the odd things you've done in a bathroom in your lifetime. What child hasn't secretly explored the substance of their waste. What pre-teen hasn't hasn't masturbated nervously. What person hasn't escaped to the bathroom during a business meeting and made a weird face in the mirror to say to the world: "You don't know I'm doing this right now. Oh there's so much you don't know."

No other moment can so clearly reveal that our public life is all, in fact, an act. An act with a purpose, but an act all the same.

Solitude welcomes a self or selves that does not, cannot, appear when in the company of others. Private selves refuse to manifest in public because other personas are at the front lines. Like mother Elephants circling their calves, our public selves form ranks. Each is a layer of armor, tweaking our interactions in the unconscious name of self defense.

When we enter the bathroom, as we are closing the door, there is a moment of transition. Our public selves are silenced, and our private selves have yet to appear. For half an instance all is still.

…until the private selves say hello.

And they can be quite dark.

They may write WHORE across the bathroom mirror, or peel a line of skin up your finger.

For this reason, solitude is not always an escape. And for some of us, most of us I contend, there are enough private selves that solitude is not always solitary at all.

Inner selves are another circle of mother Elephants, protecting the center, with new and more devious defense weaponry. One may make us pick at our skin, cut, burn, or drink till the cows come home. This is all "self-destructive behavior" but the purpose of all self destructive behavior is to protect from pain, to offer a moment of escape. This particular self's destructive actions distress another self, one that can see the unhealthyness of the behavior, and life-long SSRI prescriptions are born.

You aren't a single entity, but a household. One with all the politics, drama, violence, or delicacies of interaction of a family.

Just as there are different public personas there are many private ones. Freud said there are three. I say there are four or five. Loosely speaking these are:

1. The Imp: The self that enjoys causing problems. It sabotages all your efforts towards happiness. Gaining pleasure from the bullshit it heaps upon your other selves.

2. The Baby: The self that is encumbered by and stressed under the problems the Imp has created.

3. The Housekeeper: The one that watches it all. It comforts the baby, scolds the imp, tries its hardest to get the center to come out of its room and take control and drives everyone to gymnastics class. The Housekeeper is who we usually spend most of our alone time with.

4. The Center: The strong and transcendent self that sits behind all the squabbling and smiles because problems aren't problems and nothing matters (in a good way). This is the self all others are protecting. It is deep, deep, way the fuck deep down.

In some form and to varying degrees, these are the folks you are with when you are "alone".

Depending on how powerful and cunning your personas are, things can get dangerous.

Nina's got one devious Imp. A strong persona that only manifests in private. Though shades of it appear here and there (stealing from Beth etc), it avoids revealing itself outside of the bathroom or dressing room. The pointed exception to this is Nina's drug night, when ecstasy lowers all the gates and lets her Imp run free and unchecked (and is the only time outside of a bathroom that her hair is literally down). This persona gradually gains power in public and private moments as the stresses of the ballet force Nina to use and so acknowledge her darker energies. Lily (Mila Kunis) is only painted black. Nina is black through and through and through. By denying her shadow, Nina adds layers to it. When you hold something down that's pushing to come up, it gains momentum. If you hold your dark Imp down, it will gouge a hole in your White Swan's stomach and call the show its own.

There is one particular bathroom moment where Nina's Imp and Housekeeper do battle*, almost literally. Realizing that she's been scratching, Nina's Housekeeper frantically clips her nails. As she does, the camera moves to the right. At the same moment, partially camouflaged by camera movement, Portman's expression changes abruptly: her frantic face is momentarily calm and deeply mischievous. The Imp sabotages and the Housekeeper cleans up the mess.

The origins of Nina's war of identities aren't clear, and this is the movie's greatest strength: it doesn't explain what doesn't need to be. I don't want to know if she's actually schizophrenic or in fact a strange magic being that really does grow feathers. Why does Nina scratch? When did it start? Where is her dad? How old is she? Her relationship with her mother is clearly perverse, but one we can't exactly finger. A sexual element is hinted at, oppression is shown, but nothing is explained. A history of some kind of trauma is established, but the exact cause doesn't matter. The edges are blurry. This is familiar in avant garde film, but in mainstream cinema that usually assumes the audience is dumber than it is, it's a rarity. In Black Swan, scenes aren't spent establishing relationship back story any longer than necessary. Time isn't wasted justifying actions. Any more facts would wrench the film out of the realm of the surreal in which it belongs. When direction is good, a glance from one character to another, or from one character's persona to its rival self, is all it takes to know the deal.

In Nina's case the deal is bloody. Powerful and irreparably broken identities have to destroy each other in order for the center to find peace.

Alas, poor Nina! I knew her.

*This battle is shown throughout the film through the use of Mirrors. Aronofsky creates subtle but effective unease by manipulating Nina's reflection (Nina turns her heard as does her reflection, only half a second after).

Kartina Richardson is a filmmaker and writer. She is a contributing critic for Roger Ebert's new PBS show 'Ebert Presents and the Movies" and runs the film commentary site You can follower her on Twitter @thismoithismoi