The United States had its ego shattered, for better and for worse. When my clock radio woke me to the news of the terrorist attacks in New York and Washington, I felt the world had changed forever. Surely, as Americans and Canadians, we could no longer lull ourselves into a false sense of safety, order and peace. In all the years I can remember, we have, like children, assumed that nothing could hurt us, that within our borders we were not only invulnerable but also immortal.

Yes, there had been a few acts of terrorism; the FLQ in Quebec, the previous attack on the World Trade Center and the Oklahoma bombing, but these attacks seem relatively minor when compared with this week's violence. Then, we were able to clean up the debris, shed our tears, erect monuments to the victims, and punish the perpetrators. Things could revert to the way they were and we could go about our days believing we had a firm grip on peace.

As North Americans, we have languished far too long in a naïve, childish belief in our security. Like spoiled children, we have basked in the delusion that we were better than others, that we had all of the answers. We've felt entitled to tell other countries how to handle their problems. With our vision of a new world order, we've sought to spread a "culture of peace" around the globe, offering up our plans, ignoring the failures.

The terrorist attacks this week ended our childhood. They cracked the façade of security and jolted us out of any illusion of superiority and invincibility. We have joined the rest of the world, one that already knows the effects of terrorism and how to live in a less than peaceful world.

While the events were shocking -- and the mounting death toll will be, in the words of New York Mayor Rudolph Giuliani, "more than any of us can bear" -- what happened is not that different from what is experienced in other parts of the world; the IRA threat in England, the Basque violence in Spain, the Israeli and Palestinian conflict in the Middle East, and so on. In Peru, it's the Sandero Luminosa. I was in Lima once on New Year's when, at midnight, just to remind everyone of their destructive power, these anarchists blew up the power lines and blackened the capitol.

In Britain, I have a physician friend who tries to deny the threat of the IRA. He doesn't talk about it, but everyone knows he avoids using the Underground for fear of a bombing. I keep in touch with a psychiatric colleague in Israel. When I first met him, he was arrogantly confident; when his neighbour was killed by an Iraqi Scud missile, I saw him become a broken and humbled man.

People who live with the constant threat of danger are forced to let go of the notions that make us less than human. In most parts of the world, people learn to live with the on-going threat of danger. Children see people die. They lose their innocence. They know that life isn't fair, that good people die, bad people can survive and that war and peace are two sides of the same coin.

People who live with terror are more wary and less secure and, at the same time, they're often more human. While they may be permanently scarred, they exhibit strength and resilience. And they value life differently.

Today, as rescuers sort through the debris, it is difficult to imagine that anything good can come out of such tragedy. It is hard to ponder anything beyond revenge. But none of us can go back to life as usual. The time has come to let go of the hopes and dreams of our lost adolescence. We must come to terms with the fact that life is not always about healing.

Life leaves scars. When, as nations and as individuals, we accept them, we will have grown up -- like it or not.