PROVIDENCE — The most important force behind scientific advancement is not what you think, the 2006 winner of the Nobel Prize in physiology or medicine told graduating seniors at Brown University yesterday.

Brown President Ruth Simmons introduces Craig C. Mello, who graduated from the school in 1982 and won a Nobel Prize last fall. Brown commencement ceremonies will be held today.

The Providence Journal / John Freidah

Inspiration, persistence, hard work, even luck — sure, they’re essential, said Craig Mello, the 45-year-old molecular biologist and 1982 Brown graduate.

But, he said, “There’s another ingredient that’s even more important, and that’s discussion — being open to dialogue.”

Mello’s 1998 discovery, which transformed scientists’ understanding of how cells regulate genes, resulted from hours on the phone with his collaborator, Andrew Fire of Stanford University, with whom he shared the Nobel Prize.

“Take the time to talk to each other,” Mello urged students at a ceremony in the First Baptist Church in America, a prelude to today’s commencement at Brown. “New ideas will be born in those conversations. That’s the key to progress.”

And progress, Mello said, should encompass all of mankind. “Let’s learn to build technology that not only works here but also in Third World countries,” he said. “Western civilization is failing 85 percent of humanity.”

Mello and Fire won the Nobel Prize in October for describing the phenomenon known as RNA interference, an unexpected system by which cells switch off genes. Scientists now have a tool to turn genes on and off, learning the functions of individual genes and potentially developing drugs to stop certain disease processes. This new knowledge transformed the way biologists around the world do research, leading to science’s top honor a mere eight years after its discovery.

Mello, a Howard Hughes investigator at the University of Massachusetts Medical School, said his fascination with science was fueled in his conversations with his parents, who met as students at Brown, and his four siblings, two of whom also attended Brown.

Good conversations, like good science, challenge one’s beliefs, Mello said.

He called science a “humbling profession”: “You’re either completely wrong most of the time or only partly right at best.”

“I’m a biologist. I’m fascinated by the inner secrets of living things … but I don’t have the secrets of life. I don’t know the meaning of life.”

As a child Mello went on fossil-hunting expeditions with his paleontologist father and always knew he would pursue a career in science. But he told the students yesterday that his focus on biology began in 1978, when he read an article in the Washington Post about a process to manufacture insulin by cloning human insulin inside bacterial cells. He was awestruck that a bacterial cell could produce a human substance.

“It was really bringing home to me the relatedness of all living things,” he said.

Every student’s cells, he said, contain atoms that were once part of exploding stars. And the DNA in those cells is similar to that of every other living thing. “You are formed from stardust but you are also related to a worm,” he said.

“The systems inside our cells can go on and on for billions of years,” he said. “Our future is virtually boundless if we choose to make it so.”

The manmade insulin whose discovery so fascinated the teenaged Mello would later keep his own daughter healthy; Victoria, 6, relies on insulin injections to control her Type 1 diabetes.

“You don’t appreciate molecular biology till you have a loved one who lives because of it,” he told the graduates.

Yet in much of the world people don’t have access to those fruits of scientific progress. It’s up to scientific and academic institutions to address such problems, he said, and to think of progress in global terms. The world’s population will reach 10 billion in the lifetimes of today’s graduates, he said. “As much as we prefer organic farming, that is not going to feed that many people.

“Work together,” he urged. “Talk to each other.”

Mello is not Brown’s commencement speaker, but the closest thing. According to tradition, two students chosen by their classmates address the campus-wide commencement ceremonies, which will be held today.

Mello, instead, was addressing some of the 1,529 who will earn bachelor’s degrees. He was part of the traditional baccalaureate ceremony, involving readings, songs and prayers from several religions.

Mello told the gathering that he was “quite nervous” about giving a sermon-like speech in a historic church, something he’d never done before. But then he thought back to his own baccalaureate ceremony 25 years ago. “It turns out I couldn’t remember a single thing that was said. Or who said it, even. It was kind of liberating for me.”

But such joking aside, Mello said in an interview last week that he had an urgent message to impart. He sees the Nobel Prize as “a tremendous opportunity to make a difference that I didn’t have before.”

“It is a critical time in the history of humanity,” he said. “We are on uncharted territory.” Never before has the earth been dominated by a fast-growing technological society.

“We have to start thinking more long-term, and put a value on the things that are necessary to sustain a civilization,” Mello said in the interview. “It’s clear you cannot take the Western civilization we’re all enjoying to make it work in China and India.

“We need to embrace science as a way of solving problems,” he said.

In using the Nobel Prize as a bully pulpit, Mello has chosen an unusual course among scientists, who tend to prefer hunkering down in their labs and doing the work they love, said Kenneth Miller, a professor of biology at Brown who had taught Mello. “The scientific community in general has been too hesitant to speak out on issues of importance to the scientific community and too reluctant to take our case — the case for science — to the public,” Miller said.

Miller remembers Mello as a student in the first class he taught, but the future Nobel winner didn’t stand out among his many excellent science students. Mello’s elementary school teachers probably also would not have pegged him as a budding genius: he couldn’t read till after second grade, and not till sixth grade did he catch up academically.

Miller sees a lesson in this: “You cannot predict where scientific talent, where a genius for discovery, where great invention and great ideas are going to come from. Because of that, you have to give the best possible education to as many people as possible, and to allow talent in any field to rise as far as the talent will take itself.”

ffreyer@projo.com