In my previous post, I talked about how the existence of the universe itself is strong evidence for a Creator that transcends time and space. In this post, we'll look at how the existence of life on earth is also evidence for a Creator. Like in the previous post, I will deal with some science here, but entire volumes could be written (and have been written) on this subject in a much more detailed and technical fashion, so please consider this to be just a basic overview of the material.
Life exists on earth when at one point it did not. The question is: how did it get here? Either life arose by purely materialistic means or it was the product of some creative force. Nobel-prize winning scientist Christian de Duve writes,
"The thesis that the origin of life was highly improbable is demonstrably false. Life did not arise in a single shot. Only a miracle could have done so. If life appeared by way of scientifically explainable events, it must have followed a very long succession of chemical steps leading to the formation of increasingly complex molecular assemblages. Being chemical, those steps must have been strongly deterministic and reproducible, imposed by the physical and chemical conditions under which they took place."
De Duve states the options in a straightforward manner. Either life is deterministic, according to laws of physics and chemistry, or it is the result of a miracle. He offers a test to see which of these two choices is the most likely. If the origin of life is deterministic, then it should be possible to reproduce these steps in a lab, under the conditions supposedly existing at the time of the origin of life. In other words, we ought to be able to create life over and over again, if life began by normal chemical processes. In fact, for more than 60 years, scientists have been trying to solve the puzzle of how life began.
The first real attempt to produce proteins from inorganic matter took place in 1951 when Stanley Miller electronically charged an "atmosphere" consisting of methane, hydrogen, ammonia, and water. This atmosphere, proposed in 1924 by Russian biochemist A.I. Oparin, is called a reducing atmosphere. After a week or experimentation, Miller was pleased to find some amino acids, as well as some other building blocks of proteins, in the bottom of his apparatus. This experiment was hailed as a major break-through, because for the first time, we had been able to synthesize amino acids from inorganic compounds.
Unfortunately, this approach has several problems. The first involves the presupposed reducing atmosphere. Oparin believed that life could not begin naturally in an atmosphere containing free oxygen. As it turns out, he was correct. The chemical reactions necessary to produce amino acids always break down in the presence of free oxygen. If, therefore, free oxygen was present in the early atmosphere, then that would immediately kill the theory. It is curious to note that over the past ten years or so, much doubt has arisen over the validity of Oparin’s reducing atmosphere. Stanley Fox, who succeeded Miller, wrote, "The Urey-Miller experiment yielded amino acids under conditions then believed to be early geological. This belief has not stood the test of time."
The reason is simple. If free oxygen did not exist in the early atmosphere, then no ozone layer would have formed. Without an ozone layer, massive amounts of ultraviolet radiation would have poured down on the earth. Now, an H2O molecule is fairly easily split. The ultraviolet light would have broken that molecule up, creating hydrogen and - you guessed it - a lone, or "free" oxygen atom. John Horgan wrote in the February 1991 Scientific American that, "doubts have grown about …Miller’s assumptions regarding the atmosphere. Laboratory experiments and computerized reconstructions of the atmosphere by James C.G. Walker of the University of Michigan and others suggest that ultraviolet radiation from the sun, which today is blocked by atmospheric ozone, would have destroyed hydrogen-based molecules in the atmosphere. Free hydrogen would have escaped into space." And, Horgan didn’t add, free oxygen would have remained in the atmosphere, thus throwing a monkey wrench into any natural origin of life process. So the reducing atmosphere required for the natural formation of life is highly questionable.
A second problem is that the kind of amino acids formed were insufficient for creating life. There are two types of amino acids, and their difference is subtle but important. Amino acids are three-dimensional molecules that take a particular chemical structure, called chirality. That is, they are arranged in certain three dimensional forms which reflect polarized light in different directions. The two kinds of amino acids are called dextro-rotary and laevo-rotary, or D- and L- type acids. Chemically, there is no difference between the two. The only difference is their three-dimensional configuration, seen only as light is passed through them. Why is this an important difference? It has to do with the connecting together of such acids. Try putting a left-handed glove on your right hand. It doesn’t fit together. Similarly, a D- amino acid does not "fit" with a L- amino acid. They cannot combine effectively. In fact, the introduction of even a single D- amino acid will render all L- amino acids useless.
As it so happens, all life-giving proteins exhibit L- amino acids only. It is unknown as to why there aren’t any D- amino acid chains used in the proteins of life, and for now it is unimportant. What we need to remember is that life employs strictly L- amino acids in forming proteins necessary for life. There is no natural process that would favor one form over another, since there is no difference, chemically speaking, between the two. Chemist A.E. Wilder-Smith wrote, "In order to obtain life-supporting protoplasm and vital proteins, a source of optically pure L- amino acids must be available. Mixtures of L- and D- forms do not provide this satisfactory source. Lightning and chance can, on principle, never produce only pure laevo-rotary forms; They produce racemates only - exactly 50% D- and exactly 50% L- forms - and are therefore unsuitable for life’s proteins."
Until we can discover a way to produce long chains of purely L- amino acids by chance, then there is positively no reason to believe that life arose naturally. There has been some recent research on meteorites that suggests that polarized ultraviolet may lead to favoring one form (L) over the other (D), but that research is hardly conclusive at this point. Reading articles on the subject, we see a lot of equivocal language: This "may" have occurred...it "seems" like...it "could" be the case.... That sort of thing.
The theory that life arose through these amino acids has not advanced very far despite its initial early promises from the Miller-Urey experiment. That has led some researchers to prefer a model whereby nucleic acids came first. DNA is far too complex on its own to have come into existence by the random assemblage of molecules, so scientists prefer an "RNA-world" hypothesis. That, too, has fallen on very hard times, and a recent article in Scientific American by Robert Shapiro has taken this view to task. Here are some quotes of his from that article (found here: Feb 2007 Scientific American):
"Probability calculations could be made, but I prefer a variation on a much-used analogy. Picture a gorilla (very long arms are needed) at an immense keyboard connected to a word processor. The keyboard contains not only the symbols used in English and European languages but also a huge excess drawn from every other known language and all of the symbol sets stored in a typical computer. The chances for the spontaneous assembly of a replicator in the pool I described above can be compared to those of the gorilla composing, in English, a coherent recipe for the preparation of chili con carne. With similar considerations in mind Gerald F. Joyce of the Scripps Research Institute and Leslie Orgel of the Salk Institute concluded that the spontaneous appearance of RNA chains on the lifeless Earth "would have been a near miracle." I would extend this conclusion to all of the proposed RNA substitutes that I mentioned above."
And:
"Nobel Laureate Christian de Duve has called for "a rejection of improbabilities so incommensurably high that they can only be called miracles, phenomena that fall outside the scope of scientific inquiry." DNA, RNA, proteins and other elaborate large molecules must then be set aside as participants in the origin of life. Inanimate nature provides us with a variety of mixtures of small molecules, whose behavior is governed by scientific laws, rather than by human intervention."
And:
"The analogy that comes to mind is that of a golfer, who having played a golf ball through an 18-hole course, then assumed that the ball could also play itself around the course in his absence. He had demonstrated the possibility of the event; it was only necessary to presume that some combination of natural forces (earthquakes, winds, tornadoes and floods, for example) could produce the same result, given enough time. No physical law need be broken for spontaneous RNA formation to happen, but the chances against it are so immense, that the suggestion implies that the non-living world had an innate desire to generate RNA. The majority of origin-of-life scientists who still support the RNA-first theory either accept this concept (implicitly, if not explicitly) or feel that the immensely unfavorable odds were simply overcome by good luck."
Here's the long story short: there have been some exciting advances in biogenesis research. But too often those exciting discoveries have led to a conclusion that is unwarranted - that we have a solution for the problem of the origin of life. We don't. And we're not even remotely close. Again, as in the case with the existence of the universe, this doesn't constitute proof of God's existence, but it is highly suggestive. The immense complexity and sheer number of things that had to go right under just the precise conditions in order for life to exist are staggering. Our scientific research should continue. But when the leading scientists in the field are using analogies like a golfer playing a round of golf and then looking to tell how his round went in purely naturalistic terms, or a gorilla typing out recipes, then it would appear that deDuve's challenge - at least at this point in our research - has been answered. We do not have reproducible steps by which life arose. That leaves the miraculous as the best current option.
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