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How the Laws of Biology Reveal Purpose In the Universe
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by Michael Denton
published by The Free Press, New York NY
395 pages + appendices |
This review (C) September 5, 1998 Darel Rex Finley
In Nature's Destiny: How the Laws of Biology Reveal Purpose In the Universe, molecular geneticist Michael Denton, author of Evolution: A Theory In Crisis, explores evidence that the universe's physical rules were purposely engineered to house carbon-based life as we know it on Earth, and perhaps specifically for humans.
Denton's book is divided into two parts; "Life" and "Evolution."
Part 1: Life
Part 1 is a stunning cumulative exposition that the laws of physics — which dictate the structure of the universe — include numerous remarkable coincidences which are required for life to be possible. Denton here is not merely arguing that the universe is compatible with human life, but that there are many things about the laws which have to be just right for intelligent life to exist. This cumulative argument is, in my estimation, the greatest value of Denton's book, and thus Nature's Destiny is primarily useful as a tool for raising empirical doubts about atheism. On that basis alone, I recommend the book.
Part 1 also contains numerous references to evolution as a known fact. Almost all of these references are devoid of substantive backing, but simply presume evolution to be true, just as do the evolutionists and most popular science writers. A list of these references to evolution follows. (Only references to biological evolution or the naturalistic origin of life are included — references to the "evolution" of stars and planets are omitted.)
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page 12 line 11, page 14 line 15, page 29 line 34, page 38 line 31, page 58 line 10, page 59 lines 1-10*, page 60 line 32, page 61 line 16, page 87 line 29, page 127 line 2, page 131 line 22, page 159 lines 30-34, page 166 line 14, page 193 line 14, page 205 line 21, page 239 lines 13-18, page 240 line 14, page 254 lines 7-12 and 28-32, page 260 line 17*
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Here are two examples, which are typical of the general character of the references (emphasis added):
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The picture that has emerged from modern physics and astronomy suggests that the formation of the chemical elements for life, and planetary systems capable of sustaining life and evolution over millions of years, are only possible if the overall structure of the universe and all the laws of nature are almost precisely as they are. (page 12)
This is a particularly critical suite of adaptations because liquid water is essential to all life on earth, not only because water is the matrix in which life's chemistry occurs, but also because without bodies of liquid water no aquatic life would be possible and the evolution of complex life forms would almost certainly have been impossible. (page 29)
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Only the two references marked by asterisks make some attempt at substantive backing:
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In fact, very small amounts of ultraviolet may have played a significant role in evolution by raising slightly the average mutation rate. Without mutations, there can be no evolutionary change, and it is possible that the raised levels of mutation caused by the ultraviolet flux could have played a critical role in the evolutionary history of life. (page 59)
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But this is just a restatement of the Darwinian hypothesis. No attempt is made to solve the modern empirical problems of Darwinism, many of which Denton himself worked to expose in his own Evolution: A Theory In Crisis.
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Our design is constrained due to our evolutionary origin. We suffer spinal problems because the spinal column was not designed originally for an upright stance. . . . The recurrent laryngeal nerve loops around the aorta and back up to the larynx instead of taking a more direct route. (page 260)
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This is the argument from imperfection. Michael Behe addressed this argument very well on pages 222-225 of Darwin's Black Box. In summation, an intelligent redesign of an existing organism could leave "imperfections" of common ancestry even though the mechanism of ancestry was not evolution.
Part 2: Evolution
At least one pro-evolution writer, Gert Korthof, has seized with delight Denton's apparent flip-flop on evolution. In Part 2 of Nature's Destiny that appearance is quickly dispelled, but Denton still deserves some of the blame for the confusion. Virtually every reference to evolution in Part 1 could be replaced with a reference to the survival of species, and the argument concerning the laws of physics would not be diminished. By using the word "evolution" as he does, Denton seems to be contributing to the obfuscation of that word, rather than clarifying it as Phillip Johnson seeks to do.
When we begin reading Part 2, it immediately becomes apparent that Denton is talking about something very different from Darwin's concept of natural selection acting on random changes. Denton proposes that evolution is true in a sense, but that it is not driven by random changes, but rather by intelligently directed leaps which involve significant changes in complexity. Further, he proposes that these directed leaps are not performed by supernatural acts of interference with the laws of physics, but instead were elaborately planned into the laws of physics from the beginning. Thus, Denton finds a point of common ground between pure naturalism and the intelligent design of higher organisms — a remarkable feat.
While I must admit that the fascinating coincidences discussed in Part 1 do create an element of plausibility for Denton's idea of preplanned evolution, I would caution that Denton-style evolution is only an idea — and so far has virtually no empirical support. Part 1 of Denton's book is replete with empirical examples, but Part 2 seems lacking. Empirical solutions to Behe's examples of irreducible complexity would flesh out this part of Denton's book. Lacking such solutions, Denton seeks to minimize their importance:
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One of the most surprising discoveries which has arisen from DNA sequencing has been the remarkable finding that the genomes of all organisms are clustered very close together in a tiny region of DNA sequence space forming a tree of related sequences that can all be interconverted via a series of tiny incremental natural steps. So the sharp discontinuities, referred to above, between different organs and adaptations and different types of organisms, which have been the bedrock of antievolutionary arguments for the past century, have now greatly diminished at the DNA level.
. . .
The distance between man and chimp which seems so significant and obvious at a gross morphological level is trivial in DNA sequence space. (pages 276-277)
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This seems to be a direct implication that solutions to Behe's conundrums have been found. But then why is there no book spelling out in detail the mutational solutions Behe demands? I think that what Denton is actually doing here is using similarities as a smokescreen to hide unexplained differences. We've all heard evolutionists tell us that chimps and humans are 99% identical at the genetic level, but this doesn't resolve the question of how the complex changes were accomplished — even though those changes reside in a small percentage of the human genome's 3,000,000,000 nucleotides. Johnson discussed this point on page 91 (93 of the paperback edition) of Darwin On Trial:
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This degree of similarity [between humans and chimps] may call the importance of molecular comparisons into question, because it does little to explain the profound dissimilarities between humans and animals of any kind. Evidently the information content of the human genetic system is significantly different from that of apes, even though the arrangement of chemical "letters" looks almost the same. This point is lost on some Darwinists. In Blueprints: Solving the Mystery of Evolution, Maitland Edey and Donald Johanson casually declare that: "Although humans may look entirely different from chimpanzees and gorillas, those differences are superficial. Where it counts — in their genes — all three are ninety-nine percent identical." There is a lot of philosophy packed into that phrase "where it counts."
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What reason is there to prefer Denton-style evolution over a scenario of periodic supernatural intervention, in which new species are directly designed by intelligent modification to existing ones? I see no reason to prefer preplanned evolution in the absence of empirical backing. Denton's reasoning can be boiled down to this: "If God would meticulously adjust the laws of physics so that the universe would generate just the right kind of environment that life needs, then surely he also would have adjusted those laws so that they would originate and evolve life automatically." But this is only a philosophical preference for naturalism, and strikes me as very similar to the same preference among most evolutionists — although it is true that those evolutionists who insist that humanity is an unintended accident will not be friendly towards Dentonian evolution.
Although it is doubtless important for a scientist to make specific claims of what his thesis predicts, I think Denton is setting the bar too high:
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The hypothesis that the cosmos is uniquely and ideally fit for life cannot be secured by showing that one or two, or even several, of the conditions necessary for life appear to be ideally adapted to the ends they serve. If the hypothesis is true, then we should expect to find that all the basic conditions for life and all of the components of living organisms are ideally and uniquely adapted to the particular biological ends they serve . . . We shall see . . . that this does indeed appear to be the case. (page 104)
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The cosmos need not be "uniquely and ideally fit for life" to have been intentionally arranged for our existence — and detectably so. As Behe explained, the detection of design does not demand perfection. Perhaps Denton's perfectionist demands help to explain his idea of prearranged origin and evolution of life — for if the designer had to handcraft the life later, that might strike Denton as an imperfection of the original physical laws.
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Indeed, if it were true that the genomes of higher organisms contained vast quantities of junk, then the whole argument of this book would collapse. (page 290)
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I don't see how. The arguments in Part 1 concerning the laws of physics would still make sense, and even prearranged evolution would be hypothetically possible. A quick refresher from Behe on detection of design is in order:
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During this process . . . pseudogenes might occasionally arise and a complex organ might become nonfunctional. These chance events do not mean that the initial biochemical systems were not designed. The cellular warts and wrinkles that Miller takes as evidence of [unplanned] evolution may simply be evidence of age. (Darwin's Black Box, page 228)
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Why does Denton require so strict a teleology? This passage provides a clue:
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From a teleological perspective the origin of life must be viewed as something quite inevitable and built into the laws of nature from the beginning, just as were the properties of water and the mutual fitness of DNA and protein and all the other coincidences in the physical and chemical properties of life's constituents. (page 296)
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It appears to me that Denton is trying to use an uncompromising teleology as a glue with which to bond the idea of preplanned evolution to the strong empirical evidence for a preplanned environment. This strikes me as pure philosophy — I see no reason that evidence of a preplanned environment must necessarily carry over to a preplanned evolutionary pathway. The latter concept requires its own set of empirical verification in the form of substantive solutions to Behe. But every time Denton tries to back up his preplanned evolution, the substance is lacking:
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If indeed a tree of life consisting of a unique branching pattern of permissible or functional trajectories had been written into the DNA space, just so long as islands of function are within short mutational distances, the very nature of living things as self-replicating biochemical automata, subject to mutational change at each replicative cycle and subject to changing survival pressures as their environments gradually change, will inevitably lead to the successive discovery of these preexisting islands of biological function and to the gradual tracing out of the main branches of earth's great tree of life. (page 282)
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But this is equivalent to saying "If Darwinian evolution is possible, then it probably happened." How do we know it is possible? Denton is describing an unconfirmed hypothetical.
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Even if we could specify the design of an intelligent humanoid radically different to man, we might well find that we could not derive it via a plausible evolutionary process. (page 254)
Evolution, whether it is directed or not, can only proceed through functional intermediates, and this is bound to impose additional constraints on what life forms are possible. The origin of life, for example, is difficult to envisage, primarily because of the difficulty of imagining a credible functional sequence of increasingly more complex replicating systems leading from chemistry to the cell. (As was argued in the previous chapter, this suggests perhaps that there may be only one unique route.) A chemist, on the other hand, if he wished to create a living cell, de novo, would be free to choose a number of different strategies to synthesize the constituents of the cell and then artificially assemble them into a living whole (there is no reason why this could not be theoretically achieved). Being unconstrained by the necessity to move via a continuous functional series of intermediates, a chemist could at least in theory achieve the same end by far simpler means. (page 317)
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Denton acknowledges that there may be no plausible evolutionary path to a "radically different" humanoid, but might this also be true for humans? The difficulties involved in a naturalistic origin of life cause Denton to suggest that there is "only one unique route" to the first cell, but below the number one he seems reluctant to go. Why not zero routes? If a human chemist could construct a cell directly, with no viable intermediate forms, then surely the designer of the universe would not find the same task insurmountable.
I find Dentonian evolution intriguing, but under current evidence I would consider it much less likely than a scenario of direct intervention to create new species. If Behe's evolutionist critics ever find detailed mutational solutions to the puzzles of irreducible complexity, they may unwittingly provide empirical substance for Denton's preplanned evolution. On the other hand, if mutational solutions are not found, the plausibility of direct intervention will remain.
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