If you live in a village, the people you meet are your friends and neighbors. If you live in a city, the people you meet are in your way.

In a nutshell, that's what's wrong with us as the century changes. The angst, the ennui that philosophers have discussed over the last hundred years comes, not from our new machines, not from our science or technology, but from our anonymity.

In a small town you interact over and over with the same people. You get to know them. You need to get along with them. And you build friendly relations with them. In the city you walk or drive past thousands of people each day, most of whom you've never seen before. Everyone's a stranger. You become guarded, suspicious. And why not cut in front of that guy in the blue sedan? You'll never see him again anyway. It's a wonder we're not forever at each other's throats. But we are an intelligent race, and we adapt and get along. It's not exactly friendly, but it'll do.

Our ancestors lived in villages. They grew up with and married and worked with the other people in the hamlet. These folks, with their similar beliefs and language and traditions, were all our forbears ever knew. Life was simple. Your neighbors were your friends. Visitors - strangers - were few.

But the city beckoned with its promise of plenty. And people flocked there, worked hard, achieved many things. We now live longer, enjoy greater wealth, and pursue more opportunities than ever before, in large part because of the benefits cities bring. But a price has been paid, the price of neighborliness.

One day Crocodile Dundee appeared in the city. He came from the Australian Outback, where people lived in tiny villages and knew each other by name and a friendly "G'day!" Dundee brought that friendliness with him to the city. He walked down the boulevard, greeting everyone he passed. "G'day! G'day! G'day! ... g'day..." Then he got the picture. There are millions of us living on these streets! There's no way to greet all of us.

But Crocodile Dundee did something extraordinary. He made friends with just about everyone he did meet. And with those who tried to take advantage of him - those grasping strangers we so carefully guard against - Dundee amused himself by fighting back - as if it were some amiable barroom brawl - saying, "Aw, they're just havin' fun." He found it hard to dislike anyone in the big city. That was his nature.

Dundee is a movie fiction, of course, but his story holds a clue to how we can steer through our urban world. There is another clue, from real life. Recently a contest was held among several computer programs. The goal was to garner, either by trade or guile, the most points. If, say, program A made a trade with program B, both would earn 3 points. But if program A cheated, it could get 5 points while program B got none. (There were risks, of course, and deceit could backfire.) One program, called Tit-for-Tat, always mirrored its opponent's play. If the other program cheated, Tit-for-Tat would respond by cheating. If the other program then played fair, Tit-for-Tat would play fair as well, and so on. If Tit-for-Tat was assigned the opening move, it would always start with a fair play - a sort of good-faith gesture. No other program could defeat Tit-for-Tat. It won the contest going away.

What is it about the Aussie Outbacker and the computer program that points the way out of our estrangement? Each of them, man and machine, began any encounter with a friendly approach. They'd give others the benefit of the doubt. Yet neither fell prey to the schemes of strangers. They were both "friendly" and "alert."

"Friendly alertness" - perhaps this is a way to approach the thousands of strangers we meet each day in the city. It offers the protection of our big-city smarts and the neighborliness of our ancestors. It combines the values of small towns with the strengths of the megalopolis. If you are cynical, remember: stranger things have happened. Crime in the late 1990s has plummeted. Traffic accidents are down. "Family values" have re-emerged. Why can't neighborliness arise anew?

"Stranger" things have happened.