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.

Leslie Nielsen's childhood was a difficult one, but he had one particular shining star in his life — his uncle, who was a well-known actor. The admiration and respect his uncle earned inspired Nielsen to make a career（职业）in acting. Even though he often felt he would be discovered to be a no-talent, he moved forward, gaining a scholarship to the Neighborhood Playhouse and making his first television appearance a few years later in 1948. However, becoming a full-time, successful actor would still be an uphill battle for another eight years until he landed a number of film roles that finally got him noticed.

But even then, what he had wasn't quite what he wanted. Nielsen always felt he should be doing comedy but his good looks and distinguished voice kept him busy in dramatic roles. It wasn't until 1980—32 years into his career — that he landed the role it would seem he was made for in Airplane! That movie led him into the second half of his career where his comedic presence alone could make a movie a financial success even when movie reviewers would not rate it highly.

Did Nielsen then feel content in his career? Yes and no. He was thrilled to be doing the comedy that he always felt he should do, but even during his last few years, he always had a sense of curiosity, wondering what new role or challenge might be just around the corner. He never stopped working, never retired.

Leslie Nielsen's devotion to acting is wonderfully inspiring. He built a hugely successful career with little more than plain old hard work and determination. He showed us that even a single desire, never given up on, can make for a remarkable life.

"What would the world be if there were no hunger?" It's a question that Professor Crystal would ask her students. They found it hard to answer, she wrote later, because imagining something that isn't part of real life—and learning how to make it real—is a rare skill. It is taught to artists and engineers, but much less often to scientists. Crystal set out to change that, and helped to create a global movement. The result一an approach known as systems thinking—is now seen as essential in meeting global challenges.

Systems thinking is crucial to achieving targets such as zero hunger and better nutrition because it requires considering the way in which food is produced, processed, delivered and consumed, and looking at how those things intersect (交叉) with human health, the environment, economics and society. According to systems thinking, changing the food system—or any other network- requires three things to happen. First, researchers need to identify all the players in that system, second, they must work out how they relate to each other, and third, they need to understand and quantify the impact of those relationships on each other and on those outside the system.

Take nutrition. In the latest UN report on global food security, the number of undernourished (营养不良) people in the world has been rising, despite great advances in nutrition science. Tracking of 150 biochemicals in food has been important in revealing the relationships between calories, sugar, fat and the occurrence of common diseases. But using machine learning and artificial intelligence, some scientists propose that human diets consist of at least 26,000 biochemicals—and that the vast majority are not known. This shows that we have some way to travel before achieving the first objective of systems t hinking - which,in this example, is to identify more constituent parts of the nutrition system.

A systems approach to creating change is also built on the assumption that everyone in the system has equal power. But as some researchers find, the food system is not an equal one. A good way to redress (修正) such power imbalance is for more universities to do what Crystal did and teach students how to think using a systems approach.

More researchers, policymakers and representatives from the food industry must learn to look beyond their direct lines of responsibility and adopt a systems approach. Crystal knew that visions alone don't produce results, but concluded that "we'll never produce results that we can't envision".