On Christmas Day of last year, the Wall Street Journal published a short piece by Eric Metaxas called “Science increasingly makes the case for God” (The subtitle is “The odds of life existing on another planet grow ever longer. Intelligent design, anyone?”). If the WSJ link takes you to the subscription page, just Google the author’s name and the article’s title, and you’ll find a link that’s free.

Metaxas’s piece was wildly popular. It got about 400,000 Facebook shares and likes, and as of this morning there were 7,008 comments! Metaxas, described by Wikipedia as “An American author, speaker, and TV host” appears to be a believer, for there’s also this: “On February 2, 2012, Metaxas was the keynote speaker for the 2012 National Prayer Breakfast.”

Given its message, it’s not surprising that Metaxas’s article went viral, for it purported to give scientific evidence for God’s existence. Or rather, it claimed that science could not explain the existence of life on Earth in any convincing way, and so the only option must have been God’s creation. A few quotes will give the tenor of his piece; it’s all based on the supposed improbability of life coming into being:

Today there are more than 200 known parameters necessary for a planet to support life—every single one of which must be perfectly met, or the whole thing falls apart. Without a massive planet like Jupiter nearby, whose gravity will draw away asteroids, a thousand times as many would hit Earth’s surface. The odds against life in the universe are simply astonishing. . . . Yet here we are, not only existing, but talking about existing. What can account for it? Can every one of those many parameters have been perfect by accident? At what point is it fair to admit that science suggests that we cannot be the result of random forces? Doesn’t assuming that an intelligence created these perfect conditions require far less faith than believing that a life-sustaining Earth just happened to beat the inconceivable odds to come into being?

Metaxas then raises the “fine-tuning” argument—the supposed improbability of the universe having the right physical constants in place to allow life, and finishes off like this:

The greatest miracle of all time, without any close seconds, is the universe. It is the miracle of all miracles, one that ineluctably points with the combined brightness of every star to something—or Someone—beyond itself.

Notice that “Someone” is capitalized, and of course what Metaxas means, and what accounts for the article going viral, is that “something or Someone” simply has to be God—preferably the Abrahamic God.

The article’s popularity also shows that although many believers claim that they don’t need evidence for God, when something that seems to be evidence crops up, they seize on it avidly. Religious claims are claims about reality, and thus could conceivably be supported or refuted by evidence. If anybody says otherwise, just show them how many people liked Metaxas’s piece.

Well, I can imagine what I’d feel if I were Lawrence Krauss reading it. Along with Sean Carroll, Krauss has spent a lot of time showing that we can explain the universe without invoking God, something that is a major theme of Krauss’s most recent book, A Universe from Nothing. So Krauss, who isn’t timid, sat down and wrote a rebuttal to Metaxas’s piece. It appeared in yesterday’s online New Yorker under the title, “No, astrobiology has not made the case for God“; I’m surprised, given the magazine’s penchant for coddling faith, that it appeared at all.

But good for Krauss. He takes apart every probabilistic argument given by Metaxas, and cites new work showing that the origin of life may have been nearly certain given the chemical conditions on early Earth. I still haven’t been able to get through the arcane paper describing that work, but Krauss summarizes it nicely:

Furthermore, a recent interesting, if speculative, proposal suggests that, when driven by an external source of energy,matter will rearrange itself to dissipate this energy most efficiently. Living systems allow greater dissipation, which means that the laws of physics might suggest that life is, in some sense, inevitable.

Maybe Krauss will write a sequel to his book called A Biosphere from Nothing. He adds this:

Beyond this, two exciting scientific advances in recent decades have identified new ways in which life can evolve, and new locales where it can do so. First, we have discovered a surprisingly diverse group of new solar systems. And we now understand that, even in our solar system, there are a host of possible sites where life might have evolved that were long considered unlikely. Moons of Jupiter and Saturn may have vast oceans of liquid water, underneath ice covers, which are heated by gravitational tidal friction associated with their giant hosts. On Earth, scientists have had to revise old rules about where and how life can survive. The discovery of so-called extremophiles—life forms that can live in extreme acids, or under extreme heat or pressure—has vastly increased the set of conditions under which we can imagine life existing on this planet.

And, finally, Krauss takes apart the fine-tuning argument for God, something that Sean Carroll has also been attacking. Here’s Krauss:

The constants of the universe indeed allow the existence of life as we know it. However, it is much more likely that life is tuned to the universe rather than the other way around. We survive on Earth in part because Earth’s gravity keeps us from floating off. But the strength of gravity selects a planet like Earth, among the variety of planets, to be habitable for life forms like us. Reversing the sense of cause and effect in this statement, as Metaxas does in cosmology, is like saying that it’s a miracle that everyone’s legs are exactly long enough to reach the ground.

Krauss doesn’t discuss two other explanations for fine-tuning (the one above seems to presume that the constants were simply a given that we don’t understand, perhaps just a matter of “luck”). Those two are 1.) there could be a deeper physical principle showing that the constants more or less had to be pretty close to what they are, but we don’t yet understand that principle (this may be implied in Krauss’s emphasis on the progress of cosmology), and 2.) there might be multiple universes that (according to physical theory) have different physical constants, and life happened to have arisen in one universe that had the right constants. The “multiverse” idea isn’t just something cooked up by physicists determined to kick God out of the picture, as it arises naturally from some theories of physics; and there is evidence for some of the conditions conducive to a multiverse.

But the real flaw in Metaxas’s piece is that it’s a big fat God-of-the-gaps argument, claiming that if science doesn’t understand something by now, God must have done it. That is, of course, a dreadful way to argue in view of all the “gaps” in our understanding (most notably the origin of species) that over the centuries have been caulked not with God, but with science. And so Krauss pwns Metaxas in his final paragraph:

In the meantime, both believers and non-believers are done a huge disservice when people promulgate biased and disingenuous claims that distort what current science implies and can imply about the universe. In a society in which the understanding of science is already marginal—and where, at the same time, the continued health of modern society as it meets the challenges of the twenty-first century depends, in some sense, on our ability to utilize our scientific knowledge, both to create new technologies and to help guide rational public policies—this is the last thing we need.

Another thing we don’t need is people claiming that when science encounters a hard problem that it hasn’t yet solved, God is peeking out of that lacuna.