John Polkinghorne doesn't know anything.

USA TODAY OPINION On Religion

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Sure, he is a world-class physicist and is one of the world's leading voices regarding the relationship between science and faith. And sure, he mathematically explained the existence of quarks and gluons, got his Ph.D. in physics from Cambridge University, was knighted by the Queen for his efforts to develop ethical research standards for England's scientists, is a member of the Royal Society, was president of Queens' College, won the Templeton Prize, and wrote more than 30 books on the relationship between science and faith. But he doesn't really know anything.

For instance, does he know for certain that there is such a thing as a quark? Of course not, because no one has actually seen one. In fact, in a debate with Polkinghorne at the Smithsonian in 1999, Steven Weinberg, a Nobel Prize-winning physicist, said this: "We don't believe in quarks because we've seen them. We believe in quarks because the theories that have quarks in them work."

Likewise, Polkinghorne doesn't know for sure that there is a God. And yet, when he was at the top of his game in physics at Cambridge in 1979, he left the laboratory studying one unseen reality for the seminary to study another unseen reality. He became a priest in the Anglican Church. In addition to believing that quarks exist, he believes in a God who is driven by love to continuously create a world that is beautiful. For him, the theories that have God in them work. But he doesn't really know for sure. And he's OK with that.

Pick a side

Not everyone thinks that beliefs in quarks and God can so easily co-exist, though. Some scientists say that if you are a scientist, then by definition you can't be a person of faith. Some people of faith say that if you are a religious believer, especially one who adheres to the Bible, then you can't be a person of science. Science deals in facts, some say, and religion deals in beliefs. There is too much contradiction between the two.

But even people who don't normally think about these things have a hard time pinning down what they know for sure. Scratch just a little below the surface of most of us, and you'll find very few things on the list of what we really know. What do any of us know for certain? Not much.

Polkinghorne's level of comfort with uncertainty has its roots in reading the Hungarian chemist and philosopher Michael Polanyi, who used the term "motivated belief," and who called into question the idea that scientists deal in objective facts.

"Complete objectivity as usually attributed to the exact sciences is a delusion and is in fact a false ideal," Polanyi wrote in the 1950s. In other words, we're all coming from some kind of vantage point — always. Facts always come with interpretation. People of science are motivated to believe certain things as they proceed with their experiments, and people of faith are motivated to believe certain things as they proceed with their beliefs. Living with doubt leaves one open to additional discovery, both in science and faith.

Polkinghorne points to the example of what scientists once knew about light. For years, scientists proved that light was a series of particles. Later, scientists proved that it was waves. Then scientists proved that light acted like waves some of the time and particles some of the time. "If there is motivating evidence, you have to change your view of rationality," Polkinghorne said.

Evidence matters

Religious belief in the modern age doesn't seem to hold much room for uncertainty or doubt. In November of last year, I took Polkinghorne to the Creation Museum in Santee, Calif., to see how he would react to a hall dedicated to certainty. The museum organizers are certain that there was a six-day, 24-hour creation, that there was a literal Adam and Eve, that Darwin and Hitler belonged on the same wall of genetic engineers, and that evolution is a hoax. Polkinghorne stopped at a display that said the Bible has no record of death until Adam and Eve's sin. (Apparently even animals lived forever before the humans ate the apple.) Polkinghorne gazed at what appeared to be the museum's certainty and said to me, "The Bible may not have a record of it, but there is plenty of evidence in the fossil record." Motivating evidence changes one's beliefs. Or at least it can if we aren't holding on to our certainty too tightly.

Political extremists don't have much room for doubt, either. True believers lock into their belief systems in the same manner as religious fundamentalists, despite new information that could motivate them to alter their views. The recent display of certainty in Washington, D.C., in regard to raising the debt ceiling is a perfect example. Both sides had their own breed of fundamentalists who could not see past their own belief systems to consider that there might be another way of looking at the problem. The result was a demonizing of one group by the other, a rejection of compromise, and behavior by adults that none of us would tolerate in our children. Imagine what that debate might have looked like if someone from either side would have said, as the comedian Dennis Miller used to say at the end of his rants, "Of course that's just my opinion. I might be wrong."

Some atheists like Richard Dawkins and Christopher Hitchens are similarly locked into their certainty about the non-existence of God. If something has a religious whiff to it, their certainty takes over and reasonable discourse is the victim. Religion, politics and science all have their fundamentalists who are blinded by their so-called certainty.

Doubt, the comeback

But doubt — at least in the world of Christianity — might be making a comeback. Mother Teresa's letters, captured in the 2007 book Come Be My Light, show a servant of God and the Church plagued by her doubts. Jason Boyett writes about doubt in his book O Me of Little Faith, and even hosted a blog on Beliefnet by the same title. He says he is "a committed follower of Jesus who occasionally finds himself wondering if maybe, just maybe, we've made this whole thing up."

Rachel Held Evans' book Evolving in Monkey Town, tells her own story of being brought up in a world of certainty, only to find that it simply didn't make sense. "Most of the people I've encountered are looking not for a religion to answer all their questions but for a community of faith in which they can feel safe asking them," she writes.

It may be OK, finally, for people to admit that they don't know things for sure — whether it's about quarks, light, God or the best way forward for the nation's economy.

At 80, Polkinghorne doesn't let his own doubts keep him from believing, any more than he let his doubts about quantum physics keep him from solving problems. He still prays, still celebrates the Eucharist, still believes in some kind of life eternal.

As for belief in God, "It's a reasonable position, but not a knock-down argument," he said. "It's strong enough to bet my life on it. Just as Polanyi bet his life on his belief, knowing that it might not be true, I give my life to it, but I'm not certain. Sometimes I'm wrong."

Dean Nelson directs the journalism program at Point Loma Nazarene University in San Diego. His book, Quantum Leap: How John Polkinghorne Found God in Science and Religion, written with Karl Giberson, will be released in September.