(FORTUNE Magazine) – The commuter trains are running on schedule, and after two full days of looking at the carnage and at the courage of the people who live and work in this city, I am once again doing my extremely unimportant part of returning life to normal. But of course there is no normal. Not yet. Maybe not ever. At 8:46 we will arrive at Grand Central Station, one of the most beautiful public structures in the world, and suddenly infinitely more precious than it was a few days ago.

On Tuesday, Sept. 11, just as I do every day, I reached street level at 8:48, the exact time that the first jet full of innocent people was slamming into the World Trade Center. It was quiet where I was, four miles uptown from the fire, the smoke, the screaming. A crowd of people stood at the monitors that fill the window of the Chase Bank on the corner of 48th. Nobody was talking. On the multiple screens, one of the two towers was burning. A plume of black smoke was billowing upward into a beautifully blue late-summer sky. A light breeze was blowing, and a hint of autumn crispness was in the air.

I walked into the middle of the avenue and stood in the street, looking south. From uptown and down, east and west, in the distance and nearer by, sirens faded in and out. An ambulance whizzed by. I turned north and started my short walk to the office. I'm supposed to be at my desk by a little after nine, and I owed the chairman a call at that time whose subject seems so unimportant now that I wonder why we generally care about what we do at all. I didn't want to be late, at any rate. I fished out my cell phone and speed-dialed my secretary. "Dialing," said my StarTAC, then nothing. My BlackBerry, too, was dead. It occurred to me that there were quite a few transponders on top of the World Trade Center.

About halfway to my building, which is about 40 stories high, I noticed people crying in the street. At 9:05 a woman screamed, and I turned and saw a second mushroom of red and yellow flame belch from the side of the other tower. I watched it for a while and then kept walking. Walking seemed the thing to do.

A few years ago, after my dad died, I found myself seeing him in crowds, in shadows. I wanted him to be there, but he was not. And still I saw him in those random places. Until, one day, I didn't anymore, and then I knew he was well and truly gone.

Now I found myself wondering, as I walked through crowds of people standing inert on the sidewalks, if this World Trade Center thing was going to change the agenda for the day. We have a lot going on in our business right now. This is the start of our new season, and you don't want a lot of extraneous stuff to distract the public in the middle of that, you know.

I got to my office and noticed folks congregated in the hallway. They were crying and appeared to feel that they themselves might be in danger. I found that this idea surprised me, and a little worm of fright poked its head out of my consciousness. Danger? Here? I went to my office and called home.

I couldn't get a dial tone. It's one thing for cells to be down, but land lines? I turned on the television set in my office. On one side of the split screen, the left tower of the World Trade Center was collapsing into itself with thousands of people still inside. Could that be possible? On the other side of the screen the Pentagon was burning.

People began coming into my office uninvited. This is not an unusual thing--my door is always open--but it was not...normal. They didn't knock. A few young women were weeping. The guys were trying to look tough, but failing. I was aware that I suddenly didn't feel very managerial. I called my home again. "I'm sorry," said a recording, and I hung up.

People were jumping off the World Trade Center. A tiny body was falling, headfirst, from an unimaginable height. Then the right tower coughed up a puff of noxious smoke and ash and with a great groan disintegrated, live on TV. There were shots of terrified people running from the blast. "On any given day," the television said, "some 200,000 people work in or visit the World Trade Center complex."

We watched with that creepy sense of both observing and living in a part of history. "What's going to happen to Morgan Stanley?" said a friend of mine. "They have 25 floors in one of those towers."

I had to get out of the city. There is a car service that operates out of the space in front of our building. Five of us were going north, and although we heard that the bridges were closing, we got the last car out. On the way home we drove through the working-class neighborhood where my grandfather had a candy store and my mother grew up. Everything was still standing. In fact, the area looked a bit better than it had in the '70s and '80s, when a lot of it was gutted and burning and given up for lost.

It is now the day after the morning after. I am sitting in a train absolutely full of people headed back to work. They are reading, talking. The smoke and exploded sheetrock is still swirling above the common grave that was once the World Trade Center. New York has requested 6,000 body bags from the federal government.

The chairman of Morgan Stanley was shown on the news last night, addressing his employees over a teleconference. He did well, and spoke of going on, of how things aren't as bad as they first thought they might be. He seemed to be crying, but you can't really tell these things on video sometimes. Today they are reporting that that firm lost perhaps 40 of its 3,700 people who worked in the building.

The newspaper is full of obituaries. On the radio three children were talking about their father, who was on the 102nd floor of one of the towers. They talked in high-pitched, wounded little voices until, choked with grief and the injustice of their loss, they could not go on. More than our skyline is changed forever.

Buildings can be rebuilt. Grief, as incredible as it may seem to those who have been hit hardest, will pass, even if it never entirely goes away. As time works its inevitable magic, life will poke its sturdy head up through the rubble.

But some things will not return to the way they were before. They say the ultimate goal of terror is to create not just fear in the enemy, but the same kind of atavistic hatred in the adversary that produced the act itself, the desire to abandon all pretense of humanity, to move forward blindly to destroy the object of one's animosity. If that is true, our assailants, who believe they act with the approval of their God, have succeeded far beyond their dreams.

This nation has an astonishing ability to transcend the unthinkable and move on. Whether that is good or bad I leave to you. But some things, I think, should never be transcended.

By day, STANLEY BING is a real executive at a real FORTUNE 500 company he'd rather not name. He can be reached at stanleybing@aol.com.