Cortana, Microsoft's answer to Apple's Siri, is already become more intelligent every day, Nadella said, echoing his recent comments in Slate, where he argued that humans and machines will work together, not against each other.
"With all the abundance we have of computers and computing, what is scarce is human attention and time," Nadella said. "So having the personal digital assistant really helps me regain my time — empowers me to get more out of every moment of my life."
Nadella spoke alongside Walter Isaacson, CEO of the Aspen Institute and author of "Steve Jobs," at the Aspen Ideas Festival in Colorado, where speakers covered broad topics like the role of machines in policy and the future of Mars. The interview coincided with the announcement of Nadella's new book, "Hit Refresh," that will focus on the future of intelligent machines.
The meeting came amid a changing landscape for technology companies. Britain's vote to leave the European Union pressured stocks in the industry, just after Microsoft closed a monster acquisition of social network LinkedIn.
Microsoft's 30-year history in the U.K. means the company will continue to invest in its sizable business there, Nadella said. But Nadella said that technology companies need to make a better case for global trade creating local wealth.
"What happens in Britain, what happens in the world, matters a lot to us in our core business," Nadella said. "The real thing is, 'How do we bring back certainty that global companies and a global economy can thrive in a connected world?'"
Nadella said that Microsoft remains focused on organic innovation and what Microsoft can uniquely contribute to the world as a company. But the LinkedIn deal was "game-changing" because the two firms aligned so closely, he said.
"LinkedIn was an amazing deal for us to do because of their mission," Nadella said.