Bam. The catalyst - someone in a crowded room and noisemakers in the corner sporting fashionable bracelets emblazening the emblem, "DO YOU KNOW WHO I AM?"
It's a funny thing, actually, modern popular philosophy. The era of thought i am formally familiar with concerned itself completely with the nature of reality. The question was "DO I EXIST?" Today, no one cares about existence. Reality is taken for granted. "Sure, i exist, but WHO AM I?"
It's self-centered, i'm nearly positive, to care nothing for the nature of the envelope of universe surrounding your being - to focus on the identity of the being itself. It's definitely apathetic never to question the reality of reality, and follow Descartes' lonely trail of doubt; instead, the only journey we want to take is the journey to oneself.
Who am I?
We can approach this question is much the same manner as the question of existence. We can ask things like: upon what set of "data" - experience, actions, senses - should we base our identity? But there seems to be an important question which is never really asked, but only assumed by those seeking themselves:
Is identity something that can even be approached rationally and studied under a glass like some rare insect specimen? Is identity tangible? (Does identity exist?)
What proof have we that WHO I AM is something that we can define? (Shouldn't we know before we go to the trouble to define it?) We seem to chase phantoms searching for some elusive person called "SELF" that is supposed to exist separately from the cumulative set of ideas that make us human - Goals, loves, drives, history, mothers, beauty, holding-hands, spirit, good-books and hot-coffee, laughing-children, joy, sorrow, shade-trees on summer-days, prayer, experience, work, family, and all the concepts that are a part of us - but more than that, a part of how we relate with everyone and everything around us. Identity then requires relationship. It requires others.
The more we seek to find our "self," the farther from ourselves we find ourselves. You don't exist in a dark room meditating. You exist in the arms of small children and laughter and astonishment at the color of the shade of the apple trees. You find yourself in the eyes of your best friend.