BEIJING — In a half-empty subdivision on the outskirts of China’s capital, Yang Weidong is engaged in a quixotic struggle: to document China’s soul through an epic series of video interviews.

Before embarking on his quest, Mr. Yang, a stout 50-year-old with an impish grin and tortoiseshell glasses, had a fairly conventional life. He grew up in Beijing and witnessed the 1989 Tiananmen protests and massacre, but he had accommodated himself to the system. He taught interior design and architecture at the prestigious Tsinghua University, had a lucrative private practice and ran a hip cafe in a trendy part of town.

Then family tragedy struck. His mother, Xue Yinxian, who worked in the General Administration of Sports, came to prominence in the 1990s as a whistle-blower, publicly saying that she refused to dope Chinese athletes. In 2007, on the eve of the Beijing Olympics, officials paid a visit to her home, warning her not to speak out about doping in China, saying it would embarrass the nation. Her husband, who was convalescing from brain surgery, confronted the officials. The family says he was pushed by the officials (although they say he simply fell), and then reinjured his head, dying three months later.

His father’s death unleashed something in Mr. Yang. Suddenly, he was consumed with one burning desire: to understand how China ended up with its authoritarian political and social system.