Here is a book review from CRS on the newer Denton Book mentioned by Alan F.
Book Review
Nature’s Destiny: How the Laws of Biology Reveal Purpose in the Universe
(New York: The Free Press, 1998) by Michael J. Denton. 448 pages, $27.50 (hardcover)
Reviewed by Peter Line, Ph.D.
T he major thesis of the book is “that the cosmos is uniquely fit for human existence” (p. xii), and evidence of such unique fitness is presented. Denton builds his case by accumulating arguments to such an extent that it almost becomes repetitive, which is acknowledged by the author. He argues that it is precisely because so many arguments can be made that he can draw his conclusion. Whilst facts concerning the unique conditions necessary for biological life are not new, Denton's book does an excellent job in presenting them.
Denton appears to accept the whole evolution scenario, from the Big Bang to the Big Brain; that is, that all phenomena in the cosmos can be explained in terms of a natural evolutionary process (p. xviii). Where his views differ from the standard orthodoxy is in the method of evolution. Instead of random mutations as the raw material on which natural selection works, Denton proposes that evolution has been a directed process from the beginning. Denton suggests that the direction of evolution was preprogrammed or preordained when the universe came into existence, but appears to accept that since then evolution has run its course without added assistance. Hence, biological evolution occurs naturalistically, in a sense, but it can only follow genetic paths already mapped out for it ahead of time. According to this idea the pathways available to each organism, as the evolutionary tree of life branches out over time, are severely restricted by the options available to it in DNA space.
In the beginning of the book Denton makes it clear that the teleological argument presented is incompatible with a belief in special creation, to the extent that evidence for one is evidence against the other (p. xviii). I found this reasoning a bit strange as Denton's main evidence, as presented in the book, is the unique fitness of life on earth — that is, that organisms are optimally designed for their role. A creationist would, quite reasonably, cite this as evidence for a designer. Denton adds that evidence for his case would be consistent with or supported if “life on earth approximates to the plenitude of all possible biological forms” (p. 299). Such a notion is impossible to prove, but even if it could be shown to be true I also fail to see how this could be used as evidence against special creation.
Denton toys with the possibility that junk DNA may have coded for some of the direction that biological evolution has taken over time. In fact, he states that “Junk DNA and directed evolution are in the end incompatible concepts. Only if the junk DNA contained information specifying for future evolutionary events, when it would not in a strict sense be junk in any case, could the finding be reconciled with a teleological model of evolution” (p. 289-291). Many creationists would also support the idea that what is currently labeled as junk DNA may yet be shown to have a purpose, although not an evolutionary one.
The main argument Denton puts forth to support the notion of directed evolution is that the universe and earth, with their laws of physics, chemistry, etc., are uniquely fit to support life, and that any slight variation to one of many constants would make life almost impossible. Included in his argument is that life, if it exists elsewhere in the universe, must of necessity be similar to that on earth. This is because there is not, according to his theory, the flexibility for life to evolve in any other major way. In fact, Denton states that his hypothesis, based on the anthropocentric presumption, would be disproved if it were demonstrated that life systems based on different designs are possible, or if examples were shown where “the laws of nature are not specifically fit for life as it exists on earth” (p. 380).
The book is full of illustrations of how finely tuned are the conditions for life, and how tinkering with any part of the system would have catastrophic results. Some examples discussed include “the fitness of water for carbon-based life, the mutual fitness of sunlight and life, the fitness of oxygen and oxidations as a source of energy for carbon-based life, the fitness of carbon dioxide for the excretion of the products of carbon oxidation, the fitness of bicarbonate as a buffer for biological systems” (p. 391), etc.
Denton also discusses “complex and unusual adaptations whose evolution is very difficult to account for in terms of a gradual accumulation of successively advantageous changes” (p. 354). Among the complex systems discussed are the eye of the lobster, the eye of the scallop, the marsupial frog, and the avian lung. Here Denton should be commended for pointing out one of the main difficulties with undirected evolution; i.e., how the complex structures seen in some organisms could have come about without pre-planned design.
In conclusion, Denton’s notion of directed evolution, through a process akin to a type of ‘naturalistic predestination,’ is based on evidence for the unique fitness of complex life forms on earth. The real difficulty with his theory is in explaining how the information coding the path of evolution (both biological and non-biological) was built into the laws of nature at the creation of the universe. For example, since he accepts the Big Bang theory, how can the information to direct evolution to eventually produce the human brain be stored in atoms of hydrogen, of which the matter in the universe was once supposedly comprised.
This may not be what Denton is saying, but if the whole evolution scenario has been contrived ahead of time then what are the alternatives? There must be some information, either restricting evolution to only follow the pre-planned paths leading to viable alternatives, or directing evolution over hurdles that it can only overcome by assisted jumps. If not, then his theory differs little, if any, from undirected evolution. Hence, the question needs to be asked concerning the whereabouts of the information needed to direct the path of evolution. On this point Denton is vague, leaving the reader with the impression that he is himself very much struggling for answers.
Peter Line is a research neuroscientist living in Carrum Downs, Victoria, Australia.
