During the beer-and-pizza philosophical discussions of a college dorm many moons ago, I had presented the position that the devil was a figment of our imagination, a fig newton I had remarked since we were physics nerds struggling with angstroms, coulombs, newtons, and such.

Moreover, evil was another fig newton, the same as shadows and cold, a convenient term for the lack of light or heat, but not entities of their own. We cannot measure cold except by the absence of the calories of heat.

So evil was just the absence of good. This found traction in those days of flower children, and sent me into the world with a bit of a Pollyanna attitude, often underestimating the ability of folks to be under-good.

One would think this left me unprepared for New Yorkers, rumored to be snobbish and grumpy. But to the contrary, I discovered they are warm and kind hearted. From the subway cop who walked me over to my train so I wouldn't get lost, to the Armenian fruit vendor who was happy to show me how to sniff out the ripe peaches, the city was packed with friendly human beings.

So it was that I descended to a museum of terror and evil dedicated to thousands of New Yorkers extinguished on 9/11. Far below honking traffic and chattering kids, hundreds of us moved like silent waves around the North Tower's foundation. The pictures, stories, voices, and videos introduced us to the innocents, each so much like people we knew.

No one looked up. We silently drifted in our own space, sometimes reaching out to touch the resting place of the blameless, whether in vain attempts to comfort the departed, to steady our own hearts, or to emphasize the understanding that we all wander in fragile packages.

Looking at a crushed fire truck, I found most moving the radio recordings of cops and firemen who may have been surprised by their own courage -- all snuffed out by brutal men wicked beyond measure.

This cross-country voyage has been marked by such welcoming fellowship that I was unprepared to stare evil in the face, to imagine that so much pointless death and suffering could be unleashed from the heart of another human being.

My turmoil was not the common question of how God could permit this, but how a happy child playing tag in the streets of Saudi Arabia, filled with stories of Allah the Merciful, could grow so twisted that he would dance at the sight of a young office secretary, someone's daughter, flinging herself out a skyscraper window because she was on fire.

Between wiping my eyes, I took pictures because that is what I do, but the realization that such beasts were among us shook me with an anguish unlike anything before. I throbbed with mindless hatred, fists clenched, ready for vengeance, ready to do great evil myself.

Only hours later did a subway musician calm me with a melody that wafted between happy and sad, showing me that contradictions will exist, but that his gift of song will remain.