On the anniversary of the September 11 attacks, tributes and remembrances abound, as they should. We learn by remembering.

As a long-time lower Manhattan resident, I spent years surrounded by the spirits of those who gave their lives on that defining day of September 11, 2001.

Like all New Yorkers, the awful sights, sounds and smells of that morning and the days that followed are seared into my mind. I flew back to New York from London on September 10th, 2001, casually admiring the majestic towers on the drive into Manhattan. The fact that those twin icons would vanish 24 hours later was unthinkable.

On that crisp and beautiful morning, I was preparing to meet a colleague at 7 World Trade Center, when I was told to turn on the television. I did. And everything changed. Forever. For everyone.

Among my friends and acquaintances who lost their lives in the towers, my reflections keep returning to Paul Skrzypek. In the days before the attacks, Paul was excited about his new job at Cantor Fitzgerald. When I think of him, I can’t help but believe we really each do have our proverbial date with eternity.

How we face death is how we live life. We’re born to fear it, programmed to survive. The wonder of existence is that we can override our programming and confront death fearlessly.

The real story of September 11th, the enduring lesson, is the way different individuals confronted their own death, from the evil, murderous, barbaric bravado of the hijackers, willingly slamming themselves into buildings, to the awe-inspiring bravery of first responders climbing up to oblivion to save others. Or those graceful souls who swan-dived off the towers, the courageous passengers on Flight 93 and the countless unspoken heroes who gave their lives without hesitation to preserve the lives of friends, co-workers and strangers.

Most of all, we see ourselves in the victims of that terrible tragedy – we wonder what we have done faced with the same mortal threat. We wonder what the moment of our demise will be like. How we’ll respond. What we’ll feel. What we won’t feel. Will we muster the same bravery as so many did on 9/11? Will we rise to that final moment?

Death is the engine of life; the awareness of our limits is what drives us to exceed those limits. Much as we crave immortality, the unspoken truth is that immortality in the form of endless earthly life is the definition of hell. All meaning would disappear, all pleasure would fade, all relationships would devolve, all bonds of love would lose their immediacy. Life would become an interminable shade of gray.

And yet we’re conditioned to fear oblivion, to fight it. What we really want is to shake the bonds of time, to be timeless. To exist, but to exist in an eternal present.

We are not fully alive until we have pondered the mystery of death, until we try to face life and death with courage and dignity. The powerful lesson from September 11, 2001 is that it is possible to do so.

Many years ago, in a brief but unforgettably mysterious conversation, my 7-year-old nephew recited a short rhyme that I thought encapsulated mortality better than anything I’d ever read or heard. Though I’ve long since lost the context, I’ve never forgotten the poem:

Soon it comes to every person,

See it happen in one black curtain.

There’s really no more concise way to describe where we’re all headed. What happens when we get there is an obsession for some, barely an afterthought for others. Having grown up in a war zone, I identify more with the former group. In my view, we can’t fully live if we don’t try to understand and accept the limits (and limitations) of life.

To most who contemplate it, the concept of eternal unconsciousness, of personal extinction, of a life book-ended by oblivion, is unfathomable and bone-chilling. We are programmed to “rage against the dying of the light.” There’s a reason so much of religion centers on eschatology.

Death is life’s greatest motivator, for good and evil, fueling our futile quest to ‘matter’ – futile, because the people we seek to matter to are themselves reaching out to us to give them meaning. Picture two jumpers hurtling to earth, each reaching for the other, but neither with a foothold and both doomed to the same end. Some try to matter by helping others, some by hurting others, all with the desire to be remembered, to bridge an unbridgeable gap, to leave some kind of a mark, to prove that they existed.

Humans are impossibly lonely creatures, staring forlornly into time and space, without an anchor or a reference point, probing the depths of physics, philosophy, psychology, poetry, but forever bumping up against the unknowable.

My father, who slipped the bonds of his earthly existence more than 15 years ago, adored Edward Fitzgerald’s translation of the Rubaiyat — this quatrain in particular:

And that inverted Bowl we call The Sky,
Whereunder crawling coop’t we live and die,
Lift not thy hands to It for help–for it
Rolls impotently on as Thou or I.

With death ever-present and life ever-shrinking, we search for the light behind the black curtain. We turn to religion, to faith, to love, to poetry, to music. We get a glimmer of hope with near-death and other paranormal experiences. Some seek truth by experimenting with substances that induce altered perceptions of reality. We meditate and pray. We look to nature and art and beauty. We dream.

And on rare occasions, we get glimpses of the light behind the curtain. In the twilight before sleep (known as hypnagogic states); in moments of transcendence when our thinking brain is suspended; in vague remembrances of a home, a place of origin whose location is timeless and dimensionless; in the sudden opening — and closing — of a portal during moments of intense fear and love and pain and pleasure; in the stillness of night and nature; in strange confluences and synchronicities; in the inexplicable faith that somehow, somewhere, there is an answer.

It’s amusing that science, in its quest to deconstruct and debunk, has reaffirmed the ephemerality of the physical world, painting a wonderful and mysterious picture of a universe that is merely thought and potential. Just imagine that when you look out across the horizon, everything in your sight is energy, nothing solid, and that it’s all a thought in your mind. And that you are a thought in someone else’s mind.

We see the black curtain looming and it gives us pause, as it should. Still, we have reason to believe that behind the curtain is something even more real, more awe-inspiring, more just and fair and beautiful than the world we know.

The timeless lesson of September 11 is that we can face that looming curtain with courage and dignity.

[NOTE: This is adapted from an essay I published on a previous anniversary of the September 11 attacks.]