Now a month after the fact, cosmologist and "skeptic" Lawrence Krauss has made another attempt at damage control in the wake of that wildly popular Christmas Day article by Eric Metaxas in the Wall Street Journal. The Metaxas essay, which went viral, argued that science increasingly makes the case for God. The first try by Dr. Krauss was obviously rushed, and wasn’t published by the WSJ, though the Richard Dawkins Foundation did post it on their website. His current and much more mature effort appears in The New Yorker ("No, Astrobiology Has Not Made the Case for God").
To put Krauss’s comments in context, he has been a vociferous critic of any idea suggestive of intelligent design, and so his feigned surprise at the arguments in the Metaxas article isn’t very convincing. His own recent book, A Universe from Nothing, is interesting in that he ultimately equivocates on the meaning of "nothing," settling on a definition that is not the kind of nothing from which theists posit that the universe came. In replying to Eric Metaxas, he adopts a tone of disdain and condescension, continuing to emphasize that Metaxas
is not himself a scientist. Rather, he’s a writer and a TV host, and the article was a not-so-thinly-veiled attempt to resurrect the notion of intelligent design, which gives religious arguments the veneer of science — this time in a cosmological context.
Yet in fact the arguments Metaxas brings to bear have been published in the fields of cosmology, astronomy, and astrobiology for anyone who cares to read them in a professional scientific framework.
Dr. Krauss is honest when he says that life has yet to be discovered anywhere apart from on the Earth. This is notable since we have been looking for over fifty years. Sure, there are lots of other stars in our galaxy that haven’t been searched, but within about 120 light-years, no repeatable signal has been received. This puts an upper limit on how many radio-capable civilizations are communicating in the galaxy. True, we have found life in some very inhospitable places on and in the Earth, but this by itself is only a testament to the hardiness of life on our planet. It doesn’t necessarily say anything about the likelihood of life existing anywhere else. Despite what we know about the origin of life, it is still guesswork as to what conditions are necessary.
So having failed to find life, or at least technological civilizations, beyond Earth, what can we say about this null result? Fermi’s paradox, formulated by Enrico Fermi, asks, "If other technological civilizations are out there in our galaxy, then where are they?" If we really are your average technological species in the galaxy, it would be highly surprising that we should be the first to reach that level. A civilization capable of space travel could easily spread throughout the Milky Way within tens of millions of years. This strongly suggests that, relative to how long it has taken for humans to appear on the planet in its history of about 4.5 billion years, the first such civilization would colonize the galaxy in a relatively short period of time. So the fact that we haven’t even detected radio from elsewhere should put a big damper on expectations that other species like our own exist concurrently with us or have existed in the past.
Krauss objects to the field of astrobiology itself:
In response, I should begin by noting that the science of "astrobiology" — which, loosely stated, searches for signs of life elsewhere and explores the astrophysical and cosmological conditions that might allow for life to exist in our universe — is still in its infancy. Consensus on many issues has not yet been achieved, and the quality of work in the field varies significantly.
Rather than the cool objectivity of science, this sounds like he doesn’t care for what astrobiology is finding. Although there are many opinions about the results of this research, the field has pointed out quite a few ways in which the Earth appears to be unusual, compared to the nearly two thousand extra-solar planets discovered. The study of astrobiology also looks at just what makes Earth so habitable, and what life, at least as we’re familiar with it, requires.
As others have said before, if the facts are with you, pound the facts. If not, pound the table. What Krauss delivers to readers of The New Yorker is elegantly dressed table pounding. If astrobiology were solidly behind him he wouldn’t need to put it down.
Despite much research seeking to illuminate life’s origin, we are still quite far from a consensus on how that vital event may have happened. The rapid appearance of life on Earth, apparently as soon as it could exist here, suggests to some scientists that it will show up wherever some minimal conditions are met, including liquid water, a suitable temperature range, and the presence of organic building blocks. Yet, paradoxically, some of the smartest scientists in the world, with ample funding, are still stymied in explaining in any detail how these conditions would actually precipitate life. Dr. Krauss seems to indicate that regarding this question everything is pretty much wrapped up, and there is no mystery. That would come as a surprise to his Arizona State University colleague Paul Davies. In his book The Fifth Miracle: The Search for the Origin and Meaning of Life, Dr. Davies writes that there must be something fundamental missing in explanations of how life originated, because those explanations currently do not add up.
As for the finely tuned parameters for life that Metaxas wrote about, Krauss lists a few as well. But he also seems to argue that the statistics, far from confirming Metaxas, actually refute him. Curiously, Krauss thinks the highly unlikely parameters and the low statistical probabilities do not add together, but instead somehow cancel each other out. How this could be is not clear, but something like it would have to be true for Krauss to effectively answer Eric Metaxas. Certainly, among these parameters, there are factors that are not independent of each other. Yet nevertheless each one adds to the odds against a life-sustaining universe. This is just common sense.
We need to make sure we understand a distinction here. On one hand there are conditions that must be fulfilled for the universe to allow complex molecules needed for life. On the other hand there are conditions — including the two hundred that Metaxas alludes to — for an environment that would allow those molecules to form creatures, and also to permit technology, as in our galaxy, solar system, and planet. Krauss writes that it "is clear that many routes could have led to the same result." He gives us his day’s activities, saying there would be a low statistical probability of their all coming together as they did:
In order for me to be writing this piece at this precise instant on this airplane, having done all the things I’ve done today, consider all the factors that had to be "just right": I had to find myself in San Francisco, among all the cities in the world; the sequence of stoplights that my taxi had to traverse had to be just right, in order to get me to the airport when I did; the airport security screener had to experience a similar set of coincidences in order to be there when I needed her; same goes for the pilot. It would be easy for me to derive a set of probabilities that, when multiplied together, would produce a number so small that it would be statistically impossible for me to be here now writing.
However, this is misleading. It’s a red herring to distract the reader from the force of the argument. We’re not talking about an itinerary, but a list of parameters with small windows of possible values that permit life to arise and persist.
I find it fascinating that Dr. Krauss doesn’t dispute the number of such parameters. As a thought experiment, let’s us do a highly approximate back-of-the-envelope calculation. Very generously, we’ll give each parameter a 1 in 10 probability, that is to say a chance of 10 percent. We don’t yet have accurate numbers for all the relevant parameters, but with many of them the odds are certainly much smaller than that. Given these assumptions, a planet with Earth’s characteristics, allowing it to support human-like life, represents a very rough probability of 1 in 10200. Compare that with the number of stars in the visible universe. That number is 1022, giving us the odds of there existing even one planet like Earth in all those stars as 1 chance in 10178. Those are some very long odds. A chance of one in a million would be only 1 in 106. No wonder Krauss opts for misdirection.
I heartily agree that extraordinary claims require extraordinary evidence. Yet here we do have extraordinary evidence. Metaxas was simply saying, "Isn’t this interesting, and doesn’t it fit comfortably with a theistic understanding of our universe?" Krauss, in full denial mode, turns to just-so stories and science fiction to say that well, maybe there are many other ways to get there. Maybe so. Yet as Fermi asked, if life is common elsewhere, including intelligent life, kindly show us your aliens.
We need to have objective discussions about what the current research says, and see whether it points beyond chance and matter, or not. We owe that to ourselves as thoughtful adults. We should all be skeptical, but I submit that Krauss is a "skeptic" only when it comes to ideas he doesn’t like.