He started by talking about his childhood—his parents’ approach to life (they had opposing philosophies about child-rearing) and his love for the game of cricket. Nadella then moved on to what he calls the “watershed moment” in his life: The birth of his son, Zain, who was born with cerebral palsy. The tech CEO was 29 at the time; both he and his wife were only children in their families.

“For multiple years, I struggled with what had happened,” Nadella told the audience. His preconceived ideas of what the birth of his first child would be like were “all out the window.” As time went by, though, Nadella says the experience taught him to have greater empathy—something that, surprisingly, he says is key to innovating in tech.

“Empathy make you a better innovator,” said Nadella. “If I look at the most successful products we [at Microsoft] have created, it comes with that ability to meet the unmet, unarticulated needs of customers.”

Many of the topics Nadella addressed in his on-stage interview are also subjects he explored in his recent book, Hit Refresh, a part-memoir, part-business story published last month.

Naturally, Nadella also spoke about Microsoft. But even when discussing the tech giant he runs, he got philosophical. “The question is, ‘what is Microsoft?'” said the CEO, who joined the company in 1992. After Microsoft succeeded in making its PCs ubiquitous, it had to answer the “existential” question of why it exists, said Nadella. And here is his answer: “We build technology so that others can build technology.”

Toward the end of the conversation, Nadella did get a little geeky—and, um, used an agricultural analogy. Asked what quantum computing really is, he answered: “One fascinating way to think about quantum is that if you had a corn maze and you were trying to trace your path. a classical computer would trace, retrace again and again and on and on. Quantum is the ultimate parallel machine. It would trace all of the paths simultaneously.”