Documentarian Roger Nygard is best known for his amusing, sympathetic portrait of “Star Trek “ fans in “Trekkies” (1999), but he’s cast his net far wider in his new film, “The Nature of Existence.” It’s a record of his travels throughout the world querying all sorts of people, from religious leaders and scientists to ordinary folk, about their beliefs about the biggest questions of life. In a recent Dallas interview, Nygard called it “a ‘what’s the point of everything?’ documentary.

“How it started out, making the film—it was just me, all by myself, traveling around and interviewing people,” Nygard said. “And then I took on a partner a year and a half into the process who suggested that to tell the story, maybe you should put yourself into the film. And so I brought a second camera and he came along just filming me doing the filming. But I’m very much the reluctant participant.” In all he conducted 170 interviews over four years.

Of course, the process took preparation. Nygard sent e-mails to a great many people inviting them to sit for interviews. How many of them agreed? “A very high percentage,” he said. “Most of the scientists responded, but they love to talk about what they do. The people that don’t respond are the celebrities—they’ve got a lot of people wanting their time.”

Sometimes serendipity intervened. “But like Richard Dawkins, he’s a celebrity,” Nygard added. “There was no response to e-mails, and my travel date to England was coming up, and I was getting kind of desperate, so I put a call in to the main switchboard at Oxford, and said ‘Richard Dawkins’ office, please,’ and they said, ‘One moment, sir,’ and the phone rings and someone answers, ‘Hello.’ And I said, ‘Richard Dawkins, please,’ and the voice said, ‘This is he.’ Wow! Why didn’t I think of this before? So then he set an appointment when I got him on the phone.

“I started a journey without any particular roadmap,” Nygard explained. “I went wherever the opportunities arose. In hindsight I realized I had a process which I now call the three Rs—research, where I read a lot of books and interview authors. Then during interviews, people would say, ‘Oh, you should interview so-and-so. So, referrals. And then there’s random chance.

“Same questions for everybody,” Nygard continued. “‘Is there a soul, is there an afterlife, is there a God?’ Which drove Richard Dawkins crazy. He said, ‘Must you ask me if there’s a soul? You know what I think.’ Eighty-five questions.”

Among the people who get the most screen time are two very different religious figures, one the female pastor of the Cathedral of Hope, a gay-friendly church in Dallas, and a traveling evangelist who preaches fire-and-brimstone sermons on college campuses. In the case of the former, Nygard includes footage of her giving a very personal homily to her congregation. “Not a lot of [the subjects] tell such an interesting story,” he said. “ I happened to be there the day when she told her most deep, painful story—how she got kicked out of the seminary for being gay. That’s so filmic—that’s cinematic, when somebody’s spilling their guts like that.”

As for the evangelist, Nygard said, “He’s very entertaining, he knows how to get attention. He’s been doing it for thirty-five years, he’s an expert at holding a circus together. I had seen him when I was in college. They would turn up in the spring and preach at the University of Minnesota. I shot a mini-documentary about him at the time. I tracked him down, couldn’t believe he was doing it thirty years later. Found him, and spent a week with him.

“The whole point of the film was to go and meet people who I didn’t understand why they think that way,” Nygard said, “because once you get to know people, you’re no longer as angry or afraid of them. If you go somewhere and ask people what they think, paying attention to someone is a definition of love. If you love someone you give them your full attention. And so I traveled the world and gave people my attention. I didn’t go there to try to tell them they’re wrong, I went to listen and understand their ideas.

“The whole film is the Socratic method—it’s me asking people questions, as opposed to me telling you or them how it is.”

Nygard compared this film to his previous one. “I had a cliched pre-conception of what a ‘Star Trek’ fan was,” he said of “Trekkies.” “But by going and getting to know them it was completely changed. The same with ‘The Nature of Existence.’ I started out very angry at people—like how could people fly planes into buildings, as one example, or blow up abortion clinics, because they believe in something so strongly? Whereas I believe the opposite. We can’t both be right, so who’s right? How do we find truth?

“If your litmus test for who’s right is the one who believes it the strongest, they win. So going from anger to getting to know people and becoming much less afraid of who they are and what they believe, and arriving at a place of peace and acceptance of other people. Because we’re fearful of the things we don’t understand—the other, whover is different. And Mark Twain said the way to overcome bigotry is through travel. It’s that simple, really—travel and meet people, and overcome your cliched beliefs about them.

“Americans don’t take the time to understand other cultures. We’re very insular in this country. I went on this journey and asked people, so hopefully the film will do that for other people who maybe can’t get away or don’t travel—give them a little broader multi-cultural scope.”