Copyright (c) 1999 First Things 94 (June/July 1999): 42-45.
The Fifth Miracle: The Search for the Origin and Meaning of Life. By Paul Davies. Simon & Schuster. 400 pp. $25.
Reviewed by Michael J. Behe
Paul Davies should need little introduction to readers of First Things. A theoretical physicist and prolific author, he won the 1995 Templeton Prize for Progress in Religion. As the title of the address he gave in receiving the award indicates—"Physics and the Mind of God" (FT, August/September 1995)—he does not hesitate to think about the Deeper Meaning of his science. The deeper meaning, however, turns out to be a pretty simple proposition: our universe exhibits the remarkably narrow range of physical conditions required for life, which makes one suspect that it was intentionally set up that way. Although straightforward, this reasoning sets off alarms in many scientists’ minds. To his credit Davies ignores this peer pressure. In his Templeton Prize address he wrote:
To me, the contrived nature of physical existence is just too fantastic for me to take on board as simply a "given." It points forcefully to a deeper underlying meaning to existence. Some call it purpose, some design. These loaded words, which derive from human categories, capture only imperfectly what it is that the universe is about. But that it is about something, I have absolutely no doubt.
So far, so good. If a scientist thinks the physical evidence points to a "contrived" universe, then he should follow the data. The hitch is that Davies has definite ideas about how this design should be implemented: it ought to be restricted to the general laws of nature. "I would rather that nature take care of itself. . . . To me, the true miracle of nature is to be found in the ingenious and unswerving lawfulness of the cosmos."
Well, we all have our preferences about the way things should be. A professional scientist, however, is supposed to put aside personal biases as much as possible and let the facts speak for themselves. Admittedly, Davies comes by his preference for a self–sufficient universe honestly: as a theoretical physicist, general laws are what he studies. But in The Fifth Miracle Davies leaves behind the tidy, simple realm of physics for messy, complex biology, and grapples with the riddle of the origin of life. Unfortunately, he attempts to fit square pegs of data into the round holes of his theory, and they don’t quite fit.
A primary topic of the book is the recent discovery of "superbugs," hardy bacteria that live miles beneath the earth’s surface in temperatures over 100°C. They apparently require no sunlight because they metabolize minerals for food and energy. These exotic creatures have provoked speculation that life may exist in niches in the solar system once thought to be hopelessly sterile, such as the interior of Europa, a moon of Jupiter.
Some superbugs are so tough that they might survive a trip through outer space (say from Earth to Mars) when blasted off a planet by an asteroid collision. Davies thinks that life might even have spread around the universe by hitchhiking on meteors. Kicked up by an impact, rocks carrying frozen superbugs in suspended animation might travel for billions of years until falling onto some hospitable planet, light years from home. (Davies rather naively assumes that once microbial life reached another planet, Darwinian evolution would take over and produce more interesting life forms.)
This scenario can be granted for purposes of argument. The problem is that, as Davies realizes, it doesn’t explain the origin of life—where the very first cell came from—so it has "zero philosophical significance." At best it might say something about the early natural history of life.
What Davies thinks would have deep significance is the discovery of life that had arisen independently, as evidenced by alien biochemistry. His reasoning goes something like this: one accidental origin of life would be really tough, so two independent origins would be essentially impossible, and would show that life was intended in a "biofriendly universe." Davies is clearly excited at the prospect of truly alien life, but I doubt its discovery would change many minds. The fact is, from all we know of physics and chemistry, one undirected origin of life already looks impossible. Those folks who aren’t impressed with one origin are unlikely to be impressed by two.
The problems facing an undirected and purely chemical origin of life have, of course, been reviewed before, and Davies, outside his area of expertise, brings nothing fundamentally new to the discussion. He remarks that "When I set out to write this book, I was convinced that science was close to wrapping up the mystery of life’s origin." But if he had read The Mystery of Life’s Origin by Charles Thaxton, or Origins by Robert Shapiro, or even pertinent Scientific American articles, he might have started with a clearer picture of the relentless difficulties. Some of the unresolved questions that Davies rediscovers include the following: Amino acids can be made under prebiotic conditions, but a whole lot of interfering chemicals get made too, so how does one separate the wheat from the chaff? RNA would be a possible candidate to begin life, but since RNA is a whole lot harder to make than proteins, where would it have come from? The genetic code mediates between the two languages of life—proteins and nucleic acids—but how do mindless processes set up "codes" and "languages"?
Like everyone else, Davies has no answers to these problems, so he passes on to the reader whatever speculation has been floated. He recounts the suggestion by Carl Woese that the code assignments and the translation mechanism evolved together: "Initially there was only a rough–and–ready code, and the translation process was very sloppy." More likely that the thinking is very sloppy. Evolving code assignments together with the translation apparatus is like pulling oneself up by one’s bootstraps, instead of all at once, a little bit on the right side then a little on the left. Davies also cites a recent paper that compares the genetic code to energy levels of atomic nuclei, but only to concede that the "correspondences may be purely coincidental." He even trots out Sidney Fox’s proteinoids and Cairns–Smith’s clay crystal life—ideas that are fifteen to twenty–five years old and have led nowhere.
But Davies doesn’t really believe any of these conjectures himself. Early in the book he says he has now concluded that life’s origin is indeed mysterious: "This gulf in understanding is not merely ignorance about certain technical details, it is a major lacuna. . . . My personal belief, for what it is worth, is that a fully satisfactory theory of the origin of life demands some radically new ideas."
Using language reminiscent of William A. Dembski (see "Science and Design," FT, October 1998) he writes that "Living organisms are mysterious not for their complexity per se, but for their tightly specified complexity. . . . In short, how did meaningful information emerge spontaneously from incoherent junk?"
As a matter of principle Davies balks at the obvious hypothesis of specific design. "Science takes as its starting point the assumption that life wasn’t made by a god or supernatural being: it happened unaided and spontaneously, as a natural process." The notion of God pushing molecules around strikes him as distasteful. But it would pass muster with science, he thinks, for God (or whoever it is—Davies doesn’t like the word "God") to make "biofriendly laws" at the beginning and then butt out, allowing life to develop on its own. So from his perspective the key is to find a natural law or laws that would produce life.
This limitation leads Davies into contradictions. He explicitly says that laws cannot contain the recipe for life because laws are "information–poor" while life is "information–rich."
Can [specified complexity] be the guaranteed product of a deterministic, mechanical, law–like process, like a primordial soup left to the mercy of familiar laws of physics and chemistry? No, it couldn’t. No known law of nature could achieve this.
Nonetheless, boxed in by his presuppositions, he proposes that there may be a new type of "law," an information–generating law for which we have no evidence. He thinks the law might be something along the lines of Stuart Kauffman’s complexity theory, where systems can self–organize. Davies acknowledges that Kauffman’s ideas have met with considerable skepticism and have little evidence to support them. He also insightfully points out that with Kauffman’s ideas there is "a deeper problem of a conceptual nature." "Life is actually not an example of self–organization. Life is in fact specified—i.e., genetically directed—organization." Still, and without countering his own objections, in the end he declares that complexity theory à la Kauffman might be the way to go. One gets the feeling that he simply needed a stopping point.
The bottom line is that life’s origin and meaning remain as elusive as ever, at least within the (semi–) naturalistic framework of Paul Davies. Yet his struggle to write a book that sticks to a general–law framework, even while marveling at life’s extravagant information content, makes The Fifth Miracle a valuable and cautionary example of blinkered thought in action.
Michael J. Behe is Professor of Biochemistry at Lehigh University.