Issue 13 / January - March 1996
Evolution: A Theory in Crisis
Any large natural history museum in any Western city that has one must have an exhibit of manâ€™s supposed descent from ape-like ancestors. And every biology schoolroom will have at least a wall-poster teaching the same thing. No other scientific hypothesis is so widely or so consistently designed to appeal to the young, as if intended to shape their very imaginations so that no other account of human origins is thinkable. The authority of scientific truth, as the best kind of truth that human beings can aspire to, rests upon the confidence that a theory has not been blindly accepted from the past but tested in the present by repeatable experiments, confirmed by reliable measurements and observations within understood and accepted limits of error. In short, the claim to scientific truth depends upon the correspondence between either theory and physical reality or theory and mathematical certainty or both. Even by the most generous application of this standard, the theory of evolution as generally understood has no right to claim scientific authority: it is not supported by observation, it is not (cannot be) confirmed by experiment. How on earth it ever came to be so universally accepted is a puzzle. Given the importance and impact of the theory - it â€˜broke manâ€™s link with God and set him adrift in the cosmos without purpose or endâ€™ - that puzzle needs to be addressed. An insightful answer is given in the final chapter of Michael Dentonâ€™s very readable book.
Denton, an Australian doctor and scientist, distinguishes a special (or micro) theory of evolution from the general theory. The former would claim only that closely related species can (and did in the past) evolve from others. But the general theory (the one that is widely accepted) claims to explain the origin and current diversity of all species as purely random mutations accompanied by natural selection over a very long period of time. While Denton accepts the special (micro) theory, he demonstrates so many flaws in the general theory that it must be rejected outright: its claims cannot be softened or modified in any way that could rescue the theory.
Chapter I traces the dramatic transformation of Darwinâ€™s stance from a â€˜fundamentalistâ€™ acceptance of the Bibleâ€™s account of creation to outright rejection. Known facts about the geological age of the earth (the Bible implies 6000 years), fossil evidence of extinct species (Genesis states that all species were rescued from the flood), might justify a rejection of a literal reading of the Bible. But they do not justify a rejection of the concept of conscious design in the creation (implying a Creator). Yet, as Chapter 2 shows, this is just the position Darwin (and his followers) take: it is of the essential core of Darwinâ€™s theory that natural selection is a blind process: â€˜Darwin himself clearly stated that the mechanism responsible for ... genetic variations [must] be entirely blind to the adaptive needs and requirements of the organism. Evolution by natural selection is therefore, in essence, strictly analogous to problem solving by trial and error, and it leads to the immense claim that all the design in the biosphere is ultimately the fortuitous outcome of entirely blind random processes - a giant lottery.â€™ This idea is frequently reflected in populist remarks like Carl Saganâ€™s: â€˜given enough time, chance will work miraclesâ€™. But as anyone familiar with the relevant mathematics knows, â€˜time in itself tells us nothing of the probability of achieving any sort of goal unless the complexity of the search can be qualifiedâ€™. (Denton shows some of this complexity in Chapter 13, â€˜Beyond the reach of chanceâ€™.) The universe simply isnâ€™t old enough for even life, let alone life in all its diversity, to have arisen by chance.
Chapter 3 describes how Darwinâ€™s theory turned into a general dogma largely because of the unacceptability as scientific theory of the alternative (conscious design implying a Creator). Yet, if stripped of the philosophical and metaphysical pretensions it so quickly assumed, the theory of evolution could be respectable as a â€˜partial truthâ€™. Denton explains in Chapter 4 that there is strong evidence (supporting the restricted claims of the special theory) for closely related animals or plants evolving from each other and forming distinct â€˜speciesâ€™, the term â€˜speciesâ€™ being understood as â€˜a reproductively isolated population of organismsâ€™.
According to Denton: â€˜There are only two sorts of evidence for evolution which do not depend on actual observation of the process: finding a sequence of inter-grading forms leading unambiguously from one to another; or reconstructing them hypothetically by providing an entirely plausible genealogy including all the intermediate forms and thoroughly convincing explanation of how each stage of transformation came about.â€™ Example cases for the first sort of evidence are: the peppered moth, two species of European gull, and the droshopila species of Hawaii. Examples for the second sort of evidence include Mengels work on wood warblers of North America on Hawaiian honey-creepers by Amadon, and on small lizards of the Caribbean islands by Gorman and Atkins. How-ever, as Denton emphasizes, such evidence for special (micro) evolution in no way justifies the general theory. â€˜However attractive the extrapolation, it does not necessarily follow that, because a certain degree of evolution has been shown to occur, therefore any degree is possible. There is obviously an enormous difference between the evolution of a colour change in a mothâ€™s wing and the evolution of an organ like the human brain, and the differences among the fruit flies of Hawaii, for example, are utterly trivial compared with the differences between a mouse and an elephant, or an octopus and a bee.â€™
Denton gives good analogies and illustrative examples to argue the general principle that: â€˜while sentences, machines and other sorts of complex systems can undergo a certain degree of gradual functional change, there is invariably a limit beyond which the system cannot undergo further gradual change. To cross as it were from one â€˜typeâ€™ of system to another necessitates a relatively massive reorganization involving the redesign or respecification of all or almost all of the interacting component subsystems. Systems can undergo gradual micro-evolution through a succession of minor changes in their component structures but macro-evolution invariably involves a sudden â€˜saltationalâ€™ change [i.e. non-gradual change by â€˜leapsâ€™]. Clearly, in all such cases, the extrapolation from micro- to macro-evolutionary change does not hold.â€™ Gradual random processes are incapable of producing â€˜simultaneous highly specific correlated changes throughout [an] entire systemâ€™ which is precisely what they must be capable of if macro evolution is to work. (This argument is further elaborated in Chapter 13.)
Chapters 5 and 6 describe the â€˜typological perception of nature which sees (and classifies) organisms as distinct groups separated by non-trivial, large gaps. There is abundant evidence for this approach and historically classification schemes were based on it. However, following widespread acceptance of the general theory of evolution, some felt the need to construct literally tree-like diagrams - many branches from a single trunk and root. Inevitably, such diagrams had many blanks, many wholly conjectural â€˜branchesâ€™ needed to link known species through unknown transitionary species to alleged ancestors.
Chapter 7 discusses homology which, once thought to provide supportive evidence for evolution, turns out to be evidence destructive of the theory. 1-lomologous organs cannot be traced back to embryological development and there exist homologous limbs which, according to the theory, must have evolved from very different parts of the embryo. In short, homology does not imply common ancestry.
The subject of Chapter 8 is the key issue of fossil evidence. Darwin was expecting paleontological explorations to uncover the crucial missing â€˜linksâ€™ predicted (and required) by his theory. However, as the evidence from fossil records has grown, so too has the untenability of Darwinâ€™s theory.
To begin with, we need to know that fossils are a record only of skeletal remains: 99% of any organ ism is soft tissue which is not preserved in fossils. The coelacanth (a favourite with evolutionists) had been presented as a â€˜linkâ€™ between fish and amphibians. Yet, its skeleton is identical to that preserved in aneien fossils which are as far from having been amphibians as are any other fish, The lesson is that conclusions based on skeleton forms alone do not count for much. Insects preserved in amber from hundreds of millions years ago, identical to modern insects, provide further examples of â€˜living fossilsâ€™ which somehow evaded evolution.
Mother fossil record favourite with evolutionists is the horse series. Denton writes: â€˜The difference between Fohippus and the modem horse is relatively trivial, yet the two forms are separated by sixty million years and at least ten genera and a great number of species. The horse series therefore tends to emphasize just how vast must have been the number of genera and species if all the diverse forms of life on earth had really evolved in the gradual way that Darwinian evolution implies. If the horse series is anything to go by, their numbers must have been indeed the infinitudeâ€™ that Darwin imagined. If ten genera separate Bohippus from the modern horse then think of the uncountable myriads there must have been linking such diverse forms as land mammals and whales or molluscs and arthropods. Yet all these myriads of life forms have vanished mysteriously, without leaving so much as a trace of their existence in the fossil record.â€™
The appeal by evolutionists to the incompleteness of the fossil record as an excuse for clinging to their theory might he worth attending to if the gaps, the incompleteness, were unsystematic or random. But the facts are otherwise: â€˜The fundamental problem in explaining the gaps in ... is their systematic character - the fact that there are fewer transitional species between the major divisions than between the minor. Between Eohippus and the modern horse(a minor division) we have dozens of transitional species, while between a primitive land mammal and a whale (a major division) we have none. And this rule applies universally throughout the living kingdom to all types of organisms, both those that are poor candidates for fossilization such as insects and those which are ideal, like molluscs. If the gaps really were lhe result of an insufficient search, or the result of the imperfection of the record, then we should expect to find more transitional forms between mouse and whale than between dog and cat.â€™
The hard evidence should make any objective inquirer ask, not whether we may one day fill the gaps in our record, hut whether gradual evolution ever occurred at all: â€˜If the gaps cannot he adequately explained by appealing either to an insufficient search or the imperfection of the record, then this leaves a more or less saltational model of evolution as the only explanation of the gaps.â€™
In Chapter 9, Denton begins to draw the argument towards the conclusion that: Ultimately there is... absolutely no reason why functional organic systems should form the continuum that evolution by natural selection demands. In the world of physics and chemistry many phenomena are discontinuous. One cannot gradually convert one molecular species into another, neither can one convert gradually one type of atom into another. Between such entities there are jumps. Might not functional organic systems be similarly separated by discontinuities?â€™ He goes on: â€˜It is possible to allude to a number of species and groups such as Archaeopteryx, or the rhipidistian fish, which appear to be to some extent intermediate. But even if such were intermediate to some degree, there is no evidence that they are any more intermediate than groups such as the living lung-fish or monotremes which... are not only tremendously isolated from their nearest cousins, hut which have individual organ systems that are not strictly transitional at all.â€™
The frustration at the failure to find intermediate forms and the difficulty of conceiving of gradual functional transitions led some scientists to an alternative to gradualism, namely â€˜the concept of evolution by saltation, the idea that new organs and types emerge suddenly following some sort of massive macro-mutation.â€™ Advocates of the idea include the popular contemporary writer Stephen Jay Gould and his predecessor Goldschmidt who introduced the notion of the â€˜hopethl monsterâ€™ in his the Material Basis of Evolution (1940) as a â€˜means of getting from one type to another suddenly in one jumpâ€™.
The possibility of such a â€˜hopeful monsterâ€™ had been likened to a â€˜miracleâ€™ by Darwin. The great majority of biologists have followed him in that judgement ever since. So-called freaks of nature do, of course, occur but they have little chance of reproductive survival given that they are horn into an environment where the non-freaks (the normal) survive to reproduce. Denton sums up by saying that: While it might he theoretically possible to avoid the impasse of gradualism by opting for saltation it seems unlikely that purely random processes would ever throw together suddenly adaptations like a feather or the avian lung or the amniotic egg.â€™
In Chapter 10, the process of DNA replication and protein synthesis is explained for readers unfamiliar with the subject. Equivalents of concepts like â€˜universal Turing machineâ€™ and â€˜fault tolerant computingâ€™ can be observed in perfectly economical design in the world of molecular genetics.
â€˜The Enigma of Lifeâ€™s Originâ€™, the title of Chapter Il indicates the enormous conceptual and empirical difficulties evolution theory has faced in yet another once-promising area. It was hoped that as the nature of living organisms was more fully understood, the gap between them and inanimate forms would he narrowed. Exactly the opposite happened. The gap that separates the simplest living systems from inanimate systems seems unbridgeable: there is not a hint in inanimate systems of the DNA, messenger RNA, and the protein synthesis mechanism (implying self-replication), found in living forms.
Attempts to explain the origin of life through evolutionary means come up against two other major hurdles. The first is the so-called â€˜oxygen-ultraviolet conundrumâ€™. One has to assume that there was no oxygen in the early atmosphere because otherwise any organic compounds would rapidly oxidize. However, this assumption implies that there was no ozone to shield these compounds from deadly doses of solar radiation. In other words, this is a â€˜catch 22: If we have oxygen we have no organic compounds, hut if we donâ€™t have oxygen we have none either.â€™ The second hurdle is the shortage of time for the first life forms to evolve: â€˜An Australian group reported the remains of a simple type of algae in rocks at least 3.5 billion years old... So life had to form between 3.9 and 3.5 billion years ago. Just a few hundred million years from nothing to organic compounds to the whole DNA, M-RNA, protein system.â€™
These and other apparently insoluble difficulties led the Nobel-prize winning scientist Crick to comment:
â€˜An honest man, armed with all the knowledge available to us now, could only state that in some sense, the origin of life appears at the moment to he almost a miracle, so many are the conditions which would have had to have been satisfied to get it going.â€™ The problem of the origin of life is an example of what Denton calls â€˜the universal principle that complex systems cannot be approached gradually through functional intermediates because of the necessity of perfect co-adaptation of their components as pre-condition of function.â€™ Crick is also famous for running away from the problem by suggesting that life must have originated somewhere outside the galaxies known to us and been cast down amid cosmic dust as a â€˜seedâ€™ - his so-called panspermiaâ€™ theory.
The subject of Chapter 12 is the modern molecular biological techniques which have provided biologists with an entirely new way of comparing organisms at a biochemical level (as opposed to the classical anatomical comparisons). Again, the comparisons established that: â€˜the pattern of diversity at a molecular level conforms to a highly ordered hierarchic system. Each class at a molecular level is unique, isolated and unlinked by intermediates. Thus molecules, like fossils, have failed to provide the elusive intermediates so long sought by evolutionary biology.â€™
The gaps in the â€˜chain of beingâ€™ are seen at both empirical and theoretical level:
wherever we find significant empirical discontinuities in nature we invariably face great, if not insurmountable, conceptual problems in envisaging how the gaps could have been bridged in terms of gradual random processes. We saw this in the fossil record, we saw it in the ease of the feather, in the case of the avian lung, and in the case of the wing of the hat. We saw it again in the ease of the origin of life and we see it here in this new area of comparative biochemistry.â€™
In Chapter 13 (â€˜Beyond the Reach of Chanceâ€™) Denton illustrates the impossibility
of reaching functional complex systems via blind random processes.
In Chapter 14, we imagine ourselves in a cell magnified a thousand million times and try to grasp the wonderful reality of life. What we see is a system much more complex and perfect than any human artefact built so far. The elaborate Soviet lunar exploratory machine, the Lunakod, which moved on articulated legs, highlights by comparison the sheer ease of solutions provided in nature for such problems as self-location, stability and locomotion. The amazing storage capacity and efficiency (size and energy economy) of biological information storage and retrieval is another striking example of the ease of nature and the hardshipâ€™ humans face to match it even crudely by artifice.
Denton comments: â€˜According to Paley, we would never infer in the case of a machine, such as a watch, that its design was due to natural processes such as the wind and rain; rather, we would be obliged to postulate a watch-maker. Living things are similar to machines, exhibiting the same sort of adaptive complexity and we must, therefore, infer by analogy that their adaptive complexity is also the result of intelligent activity.â€™ And he adds: â€˜The conclusion may have religious implication but it does not depend on religious presuppositions.â€™
Chapter 15 (â€˜Priority of Paradigmâ€™) gives Dentonâ€™s explanation of why the theory of evolution has been so pervasive in our age despite overwhelming contrary evidence.
It is a modern example of a scientific community defending a theory just as tong as ii holds sufficient intrinsic appeal.â€™ He likens it to the defence by medieval astronomers of the Ptolemaic theory of the heavens, and by the eighteenth-century chemists of the phlogiston theory of combustion.
There is not space here to argue at sufficient length against the widely held stance of modern scientists that the concept of a Creator-God is of no relevance to a properly scientific understanding of how the natural world is or how it operates, that, in brief, it cannot he a part of any scientific explanation or theory. We must insist, however, that scientific knowledge cannot exist (any more than its dominant theories can com -about) in some sort of vacuum, isolated from the complex of human knowledge, attitudes and relationships. The social implications of the â€˜central claim of Darwinian theory that humanity was not born by the intentions of a Deity hut by a completely mindless trial and error selection of random molecular patterns...â€™ have been, in general, very had. A theory so certainly false should never have imprisoned scientific imagination for as tong as it has. Ii could not have done so if the aspiration to scientific knowledge had been tutored in the humility that comes with a serious, religious consideration of our status as creatures and servants of God. Only a religious perspective teaches that all human curiosity - its perceptive faculties, its intelligence and the instruments it devises to extend its powers - exists as the gift of the One All-Merciful God who created us and the intelligibility of the world so that we might draw nearer to Him. At least in the field of biology, the alternative to believing in a Creator did not, as is claimed, offer freedom from dogmatism: the lasting value of Dentonâ€™s hook is to have demonstrated that reality with clear argument and a large body of hard evidence.