Sometime in the early 1960s, a significant thing happened in Sydney, Australia. The city discovered its harbor. Then, one after another, Sydney discovered tots of things that were just sort of there-broad parks, superb beaches, and a culturally diverse population. But it is the harbor that makes the city.

Andrew Reynolds, a cheerful fellow in his early 30s, pilots Sydney ferryboats for a living. I spent the whole morning shuttling back and forth across the harbor. After our third run Andrew shut down the engine, and we went our separate ways-he for a lunch break, I to explore the city.

"I'll miss these old boats," he said as we parted.

"How do you mean?" I asked.

"Oh, they're replacing them with catamarans. Catamarans are faster, but they're not so elegant, and they're not fun to pilot. Hut that's progress, I guess."

Everywhere in Sydney these days, change and progress are the watchwords（口号）, and traditions are increasingly rare. Shirley Fitzgerald, the city's official historian, told me that in its rush to modernity in the 1970s, Sydney swept aside much of its past, including many of its finest buildings. "Sydney is confused about itself," she said. "We can't seem to make up our minds whether we want a modern city or a traditional one. It's a conflict that we aren't getting any better at resolving（解决）.”

On the other hand, being young and old at the same time has its attractions. I considered this when I met a thoughtful young businessman named Anthony. "Many people say that we lack culture in this country," he told me. "What people forget is that the Italians, when they came to Australia, brought 2000 years of their culture, the Greeks some 3000 years, and the Chinese more still. We've got a foundation built on ancient cultures but with a drive and dynamism of a young country. It's a pretty hard combination to beat."

He is right, but I can't help wishing they would keep those old ferries.

In 1916, two girls of wealthy families, best friends from Auburn, N. Y.—Dorothy Woodruff and Rosamond Underwood—traveled to a settlement in the Rocky Mountains to teach in a one-room schoolhouse. The girls had gone to Smith College. They wore expensive clothes. So for them to move to Elkhead, Colo. to instruct the children whose shoes were held together with string was a surprise. Their stay in Elkhead is the subject of Nothing Daunted: The Unexpected Education of Two Society Girls in the West by Dorothy Wickenden, who is a magazine editor and Dorothy Woodruff's granddaughter.

Why did they go then? Well, they wanted to do something useful. Soon, however, they realized what they had undertaken.

They moved in with a local family, the Harrisons, and, like them, had little privacy, rare baths, and a blanket of snow on their quilt when they woke up in the morning. Some mornings, Rosamond and Dorothy would arrive at the schoolhouse to find the children weeping from the cold. In spring, the snow was replaced by mud over ice.

In Wickenden's book, she expanded on the history of the West and also on feminism, which of course influenced the girls' decision to go to Elkhead. A hair-raising section concerns the building of the railroads, which entailed（牵涉）drilling through the Rockies, often in blinding snowstorms. The book ends with Rosamond and Dorothy's return to Auburn.

Wickenden is a very good storyteller. The sweep of the land and the stoicism（坚忍）of the people move her to some beautiful writing. Here is a picture of Dorothy Woodruff, on her horse, looking down from a hill top: "When the sun slipped behind the mountains, it shed a rosy glow all around them. Then a full moon rose. The snow was marked only by small animals: foxes, coyotes, mice, and varying hares, which turned white in the winter."

A machine can now not only beat you at chess, it can also outperform you in debate. Last week, in a public debate in San Francisco, a software program called Project Debater beat its human opponents, including Noa Ovadia, Israel's former national debating champion.

Brilliant though it is, Project Debater has some weaknesses. It takes sentences from its library of documents and prebuilt arguments and strings them together. This can lead to the kinds of errors no human would make. Such wrinkles will no doubt be ironed out, yet they also point to a fundamental problem. As Kristian Hammond, professor of electrical engineering and computer science at Northwestern University, put it: "There's never a stage at which the system knows what it's talking about."

What Hammond is referring to is the question of meaning, and meaning is central to what distinguishes the least intelligent of humans from the most intelligent of machines. A computer works with symbols. Its program specifies a set of rules to transform one string of symbols into another. But it does not specify what those symbols mean. Indeed, to a computer, meaning is irrelevant. Humans, in thinking, talking, reading and writing, also work with symbols. But for humans, meaning is everything. When we communicate, we communicate meaning. What matters is not just the outside of a string of symbols, but the inside too, not just how they are arranged but what they mean.

Meaning emerges through a process of social interaction, not of computation, interaction that shapes the content of the symbols in our heads. The rules that assign meaning lie not just inside our heads, but also outside, in society, in social memory, social conventions and social relations. It is this that distinguishes humans from machines. And that's why, however astonishing Project Debater may seem, the tradition that began with Socrates and Confucius will not end with artificial intelligence.