Wednesday, October 29, 2003

Anthropic principle in Cosmology Conference Story in NYT


Saw this interesting item in the NYT. Hat tip to Hugh Hewitt.

As molecular biologist, I love science and try to be at least aware of some of the latest rumbling in some other fields. Cosmology has got to be one of the most interesting things going on scientifically.

Excerpts:
CLEVELAND — Cosmology used to be a heartless science, all about dark matter lost in mind-bending abysses and exploding stars. But whenever physicists and astronomers gather, the subject that roils lunch, coffee breaks or renegade cigarette breaks tends to be not dark matter or the fate of the universe. Rather it is about the role and meaning of life in the cosmos.

Cosmologists held an unusual debate on the question during a recent conference, "The Future of Cosmology," at Case Western Reserve University here.

According to a controversial notion known as the anthropic principle, certain otherwise baffling features of the universe can only be understood by including ourselves in the equation. The universe must be suitable for life, otherwise we would not be here to wonder about it.
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Scientists agree that the name "anthropic principle," is pretentious, but that's all they agree on. Some of them regard the idea as more philosophy than science. Others regard it as a betrayal of the Einsteinian dream of predicting everything about the universe.
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Dr. Gross, director of the Kavli Institute for Theoretical Physics in Santa Barbara, Calif., had agreed to lead a panel discussion on the notorious principle. Often found puffing on a cigar, he is not known to be shy about expressing his opinion.

"I was chosen because I hate the anthropic principle," he said.

But playing a central role in defending the need for what he called "anthropic reasoning" was Dr. Steven Weinberg, a Nobel laureate from the University of Texas. Like Dr. Gross, Dr. Weinberg is a particle physicist who is known for being a hard-core reductionist in his approach to science, but he evinces a gloomy streak in his writings and his talks. He is still famous for writing in his 1977 book, "The First Three Minutes," "The more the universe seems comprehensible, the more it also seems pointless."
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... the cosmological constant, it is a number that measures the amount of cosmic repulsion caused by the energy in empty space. That empty space should be boiling with such energy is predicted by quantum theory, and astronomers in the last few years have discovered that some cosmic repulsion seems to be accelerating the expansion of the universe. But theoretical attempts to calculate this constant, also known as lambda, result in numbers 10 E+60 times as high as those astronomers have measured.
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Dr. Gross questioned whether the rules of the anthropic game were precise enough. What were the parameters that could vary from universe to universe? How many could vary at once? What was the probability distribution of their values, and what was necessary for "life"?

Anthropic calculations are inherently vague and imprecise, he said. As a result, the principle could not be disproved. But he was only getting warmed up. His real objection, he said, was "totally emotional."

Ascribing the parameters of physics to mere chance or vagaries of cosmic weather is defeatist, discouraging people from undertaking the difficult calculations that would actually explain why things are they way they are. Moreover, it is also dangerous, he declared to ringing applause.

"It smells of religion and intelligent design," he said, referring to a variety of creationism that argues that the universe is too complex to have evolved by chance.
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Dr. Weinberg replied that the anthropic principle was not really a part of science, but rather "a guess about the future shape of science."

"If we didn't have things in our universe that seem peculiar, like the value of the cosmological constant, we wouldn't worry about it," he said.

Dr. Weinberg compared the situation to a person who is dealt a royal flush in a poker tournament. It may be chance, he said, but there is another explanation: "Namely, is the organizer of the tournament our friend?"

"But that leads to the argument about religion," he said to much laughter.

In fact, Dr. Weinberg said, the anthropic principle was "a nice nontheistic explanation of why things are as nice as they are."

By then the audience was squirming to get in on the action. Hands were waving as Dr. Gross called the session to an end. "Clearly there is a diversity of opinion," he intoned. "Some people find the small value of cosmological constant so bizarre that only the anthropic principle will pick it out."

Nobody who adheres to the anthropic principle, he said, would hold on if there were "an honest old-fashioned calculation," that explained the cosmological constant.

Given the floor for the last word, Dr. Weinberg agreed that it was too soon to give up hope for such a breakthrough. "I'm prepared to go on hoping that one will be found," he said. "But after the passage of time one begins to entertain other possibilities, and the anthropic explanation is another possibility."

Applying that mode of reasoning, he said, could help make the cosmological constant less peculiar,

"But we don't know if that's the help that we really deserve to get," he concluded.

And it was time for lunch.

Dr. Gross reported later that younger physicists had thanked him for his stand.

Dr. Weinberg said the panel had generated more fuss than the subject deserved.

"Those who favor taking the anthropic principle seriously don't really like it," he said, "and those who argue against it recognize that it may be unavoidable."

Fascinating discussion. The scientists are looking at the data and are honest about the implications and honest that some of their own discomfort with ideas are emotional more than technical.

In the end, science and religion have the same goal: truth. We want to understand the universe and our place in it. As a Christian, I believe God gaves us minds to explore our universe and we should use it. As a scientist, I recognize that there are limits to our intellectual capability. Use all of what we got but recognize that science isn't the end all and be all at arriving at truth. I want to find the capital T, Truth, and I'll use whatever tools I can get my hands on. And I recognize that there will be variable degrees of certainity in our knowing the truth and reality.

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