Ray Dalio, the billionaire founder of the Bridgewater Associates—the world’s largest hedge fund—has written a new book about where the American Empire lies in the arc of history, and what the economic future holds. He discussed the book, The Changing World Order, in an interview with The New York Times’ Dealbook column.

Dalio examines 4 empires in the book: the Dutch, British, American, and Chinese, and writes that we could be seeing the rise of another Chinese Empire. Any attempt by the U.S. to regulate China won’t work, Dalio says, concluding that if China continues to rise while the U.S. declines, “what matters most is whether or not each can do so gracefully.”

In researching the book, Dalio said he was surprised most by how much natural disasters impact economies, and that he came away with a greater understanding of the connections between internal and external conflicts, the cost of war—both financial and non—and the affect of nature. But Dalio doesn’t see himself as a pessimist; “the worst case doesn’t affect most people as badly as it sounds when you read it,” he told The Times.

Dalio remains unconvinced that the economy’s current challenges can be solved by central bankers, and has recently delved more into cryptocurrencies. He added that if more people understood the connection between monetary policy and the value of their money, and the resulting cycles of the economy, outcomes would be more positive. The Times quoted him in conclusion: “I have a principle: If you worry, you don’t have to worry. And if you don’t worry, you have to worry.”