May 13, 2010
We go our ways and live our lives. All seems ordinary, normal. Yet all is extraordinary, astonishing. We human beings sit roughly midway between atoms and galaxies, between the infinitesimally small and the immensely large. And both—atoms and galaxies—must be so perfectly structured for them—for us—to exist.
It’s called “fine-tuning,” and it’s all so breathtakingly precise that it cries out for explanation. To some, it may seem obvious that “God designed it,” that fine-tuning leads to God. But “obvious” can mislead, and there are other explanations.
“Fine-tuning” is perhaps modern theology’s strongest “design” argument for the existence of God. That’s why I start with a leading proponent, Robin Collins, a young Christian philosopher trained in physics.
“Scientists have discovered that the basic structure of the universe has to be just right in order for life to occur,” Collins says, “particularly intelligent, conscious observers like ourselves.” He highlights three basic sources of fine-tuning: 1) the fine-tuning of the laws of nature, 2) the fine-tuning of the constants of physics (those numbers, or “free parameters,” needed to make equations fit the physical world), and 3) the fine-tuning of the initial conditions of the universe.
According to Collins, “the laws of nature have to be just right in order for life to occur. For example, without gravity, or a universal attractive force, then matter in the universe would never clump together into stars and planets. Without the strong nuclear force (the force that holds neutrons and protons together), then all protons would repel each other and atoms with atomic numbers greater than hydrogen could not exist. Without the electromagnetic force, complex chemistry would be impossible.”
Regarding the second source of fine-tuning, the constants of physics, Collins uses Newton’s law of gravity, where its force equals g times the first mass, times the second mass, divided by the distance between the masses squared. That “g” is a critical number. If it were one half of what it is, we would weigh one half of what we do.
The most extraordinary case of fine-tuning of the constants of physics, Collins asserts, is the cosmological constant, which seems to be a pressure-like force of empty space that opposes gravity. Though extraordinarily weak, it is not zero, and it seems to be fine-tuned to about one part in 10120. (Collins explains this astounding fine-tuning by drawing an analogy: “If you had a ruler stretched across the entire universe and thought of it as a radio dial, it would have to be fine-tuned to much, much less than 1 trillionth of an inch.”)
As for the third source of fine-tuning, the initial conditions of the universe, Collins claims that they had to have been just right in order for life to occur—specifically, very low entropy to have usable energy.
He comes to the conclusion that fine-tuning provides “strong evidence of a Designer, a being who set the universe up, structured it in just the right way, in order for conscious, intelligent beings to come to exist.”
The laws of nature. The constants of physics. The initial conditions of the universe. Collins makes a threefold “fine-tuning case” for God.
Sure, I’d like God to exist. But I shy from defending God with “design.” I’d feel ever vulnerable to scientific discovery.
Ernan McMullin, a philosopher of science trained in physics and a Catholic priest, envisions fine-tuning as a radically new kind of argument for God. “In order to get a life-bearing universe,” he says, “the laws of nature have to be pretty much what they are. Now the question is, what do we make of that?”
McMullin sees only four possible answers: luck, premature science, the multiverse theory, and a Creator God. He rejects “luck” as being wildly unlikely. He rejects premature science because “there are so many coincidences in the laws of nature that it’s not very likely that they could all follow from a simple, single theory.” He rejects the multiverse (of perhaps an infinity of universes) as requiring “an enormous additional postulate” and being “quite extreme.” He says: “To postulate something so totally new, something for which there is no evidence at all, is wishful thinking.”
So he concludes that “there is only one other alternative as far as I can see and that is to hearken back to the ancient tradition of creation theology, the idea that the universe is the work of a Creator, and that the Creator has a special role for humans within this universe.”
What about what the “God hypothesis” has to assume? “Not only do we have to postulate some ethereal spiritual being for whom there’s no evidence whatsoever,” I say, “but we also have to postulate that being to be so complex that it can create whatever complexity we find here.” So doesn’t conjuring up God, I ask McMullin, make the problem doubly worse?
“No, I don’t agree with that at all,” he shoots back instantly. “First of all, it’s by no means necessary that a being sufficiently powerful to create our universe would have to be complex. Scientists themselves are accustomed to finding simple answers to very complex questions. More importantly, we can ask whether there should be a universe in the first place. The question of existence is a unique question. It’s a question which the scientists can’t address and shouldn’t address. This is not a shortcoming of science, this is not a gap; this is simply a question that is of a different sort. And the religious believer has always asked it and has always given an answer to it: There is a being responsible for the fact that the universe exists, even if there are an infinity of universes or a universe which has always existed.”
McMullin says: “You have a choice between two alternatives: You either stop with the universe as given, as physicists do. Or you take the one step further and you postulate a single being and a single act of creation.”
But this doesn’t answer why there should be that kind of God in the first place?
“There has to be a stopping point,” McMullin asserts. “The question is: Which is the better stopping point? I myself think that it’s an issue that has never come up before in the history of this discussion because, previous to this, the way in which God entered into it was as an answer to some specific of the universe, like design, for example. My argument has nothing to do with this. It is not saying, ‘Look, there’s something science can’t explain which we can explain with God.’ That’s not it. What is being postulated here is a reason why there should be anything at all for physics to study in the first place.”
To McMullin, fine-tuning is different in kind from traditional arguments from “design”—and it bores to the core of the essence of existence itself.
I’m exhilarated by profound insight, but I fear superficial semantics. McMullin’s first a priest, I remind myself, then a scientist. What about someone first a scientist, sensitive to spiritual ideas, but not wedded to them?
Physicist Michio Kaku, whose religious background includes both Buddhism and Christianity, tells a story. “When I was in second grade,” he says, “my teacher made a statement that shocked me to the core. She said that God so loved the Earth, he put the Earth just in the right place from the sun. Not too close because the oceans would boil; not too far because the oceans would freeze. I was floored! That’s right! The Earth was in just the right place relative to the sun! Venus did have a scorched surface. Mars was a frozen desert. We are just right from the sun. Every planet discovered is either too hot or too cold. How to explain Earth’s great fortune, the so-called Goldilocks paradox?”
Kaku continues: “How many Goldilocks zones are there? You start to count them, and you realize that we are just right in so many different areas of physics. It’s like a jet airplane being ripped apart by a hurricane and then suddenly reassembled intact after the storm. That just doesn’t happen by accident. So we have this paradox: Why are we in so many Goldilocks zones?”
He goes on: “There are two philosophies you can take. First, the Copernican principle says that there’s nothing special about humans, nothing special about our piece of the universe. We’re very ordinary. We exist, as do trillions of stars and planets. We’re insignificant. We’re nothing. We’re less than nothing. … Second, the anthropic principle says we are special. We are so special that we’re perhaps the only universe among a whole collection of universes that has intelligent life. Our universe, in some sense, knew we were coming.”
Does this line of argument lead to God? “There’s another way to explain it,” Kaku says. “It could be that universes evolve—that as some universes die, baby universes are created by advanced civilizations, and the DNA of these new universes is precisely the physical constants of our universe. Of course, they would have to be unimaginably advanced, but this controlled evolution of universes is consistent with the laws of physics. It would then be no accident that our universe has these conditions because it was a spin-off of another universe. In some sense, we would then not be winners of a cosmic jackpot, but simply winners of survival of the fittest.”
But even if super-advanced civilizations were creating universes, there had to have been a first universe—and there the fine-tuning problem would reassemble itself and re-emerge, stronger than ever. No?
No one knows the non-God, nonsupernatural explanation of fine-tuning better than physicist Victor Stenger, who makes an aggressive case for atheism. Stenger is raring to refute the fine-tuning argument for God.
He begins by agreeing that “there’s no doubt that if many of the constants of physics were changed, we would have a different universe—we would not have life as we know it. However,” he adds quickly, “one has to realize that life is just basically organized systems, and it’s perfectly possible to conceive of life forms totally different from ours. We can’t use our limited knowledge of our own universe to predict how some other universe might look.”
Stenger claims that when he played “a little game with the constants of physics” by changing them randomly over 10 orders of magnitude, he still “got over half of the stars living the same billion years or more.” This indicates, he says, “that the age of stars is not all that fine-tuned, and that once you have long-lived stars, you have fulfilled a primary requirement to have some kind of complex life form because, after all, complexity does arise out of simplicity pretty naturally.” Stenger concludes that “the fine-tuning argument for God fails right away because it only applies to one form of life, and we have no way of ruling out all conceivable forms of life.”
He gives another argument against the fine-tuning argument for God. “If God made the universe and God is perfect,” Stenger says, “why would he have to fine-tune it at all? If God designed the universe for life, especially for human life, then why wouldn’t God have humans able to live anyplace? Live on every planet! Live in space! God could have done that.” Further, Stenger adds, “our planet itself is not exactly such a great place: It’s mostly water, sunlight causes cancer, disasters are commonplace. So if God really created the universe for us, he didn’t do a very good job.”
He continues: “The argument for the creation requiring outside forces was a good one until cosmology came along in the 20th century and showed that it could be perfectly natural. We don’t know exactly how it happened, but we certainly have plausible explanations that solve the ‘God of the gaps’ problem.” (“God of the gaps” is the argument that if you can’t explain something with science, you therefore invoke God to explain it.)
The typical atheistic refutation of the fine-tuning problem postulates that there are many universes, Stenger says, “which would mean that we just happen to be in the universe that was suited for our form of life because that’s the only place we could possibly be. But even within a single universe, there’s nothing that requires that only our particular form of life is possible.”
Stenger offers five natural reasons why the fine-tuning of the universe does not lead to God: life need not be like us; fine-tuning is not that fine; new theories, like cosmic inflation, solve mysteries; God of the gaps never lasts; and, after all, our life on earth isn’t so great!
The “fine-tuning problem” demands explanation. Here are four.
1) Brute fact and luck: The one universe that just happens to exist also just happens to support life.
2) The universe can be only one way, one set of equations that explain all. (But even so, why would this “one way” generate life?)
3) Multiple universes: such that everything will happen “somewhere”—including us.
4) A Creator God who designed the universe.
Here’s what I think. Multiple universes would explain the fine-tuning of our universe, but a fine-tuned “universe generator” for the vast ensemble of multiple universes is still needed.
As for supernatural explanations, a traditional God is but one of many untold options. Moreover, new kinds of physical laws may seem supernatural.
Where do we stop? What’s the terminus of explanations? That’s the question!
Our universe? Multiple universes? Or something beyond?
For the riddle of existence, fine-tuning is our biggest clue. That’s why it edges us closer to truth.
Robert Lawrence Kuhn speaks with Robin Collins, Victor Stenger, Ernan McMullin, and Michio Kaku in “Does a Fine-Tuned Universe Lead to God?”—the 15th episode in the new season of the Closer To Truth: Cosmos, Consciousness, God TV series (54th in total).
The series airs on PBS World (often Thursdays, twice) and many other PBS and noncommercial stations. Every Thursday, participants will discuss the current episode.
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