Why David Pearce's "Evidence for Design" fails to disprove Evolution: Parts 1 & 2

 

By Ken Gilmore
Source: Click here

David Pearce’s “Evidence for Design”[1] is one of two Christadelphian-authored works of pseudoscience that the Christadelphian Magazine and Publishing Association sells.[2] Given that the fact of evolution has not been in doubt for well over a century[3] it reflects both Pearce’s gross ignorance of the subject that he criticises, as well as a failure of the CMPA to maintain the quality of material that it sells.

Pearce’s thesis is simply the argument from design dressed up in modern clothing. At heart, it is an argument from ignorance

I cannot imagine how X evolved. Therefore it never evolved.

The flaw in this argument is painfully easy to see. Just because Pearce cannot imagine a plausible evolutionary pathway for the evolution of a structure does not mean that one does not exist. Anyone with even a nodding acquaintance with the professional literature will be aware that the cumulative effect of mutation and selection is capable of producing design. In fact, evolutionary algorithms, which exploit this Darwinian mechanism are more than capable of producing design without a designer.[4]

Another problem with the argument from design is that creationists such as Pearce are unwilling to accept the fact that suboptimal, flawed design is rife in the natural world. If Pearce is willing to exult in what he thinks is elegant design, then he is obliged to explain why God would create flawed, incompetent structures such as:

• The male prostate, which stupidly encircles the urethra, resulting in an increased likelihood of urinary obstruction when it enlarges in old age
• The vertebrate eye, which has the light-sensing cells pointing backwards away from the light. This results in an increased chance of retinal detachment and increases the likelihood of impaired vision from diabetic retinopathy. An eye with the light cells pointing towards the light (such as seen in the octopus) is immune from such problems.
• The recurrent laryngeal nerve in humans and other mammals, which makes a pointless detour past the larynx, down the neck, under the aorta, then back to the larynx. It does not need to make this path – the nerves innervating the larynx could easily branch off and directly supply the larynx.
• The human pancreas, which forms from two buds, rather than a single structure. Errors in embryogenesis can result in a ring pancreas which envelopes the duodenum, causing obstruction
• Human sinuses drain poorly, and are prone to mucous clogging and infection.
• Human testicles make a stupid descent from inside the abdomen, through the abdominal wall and outside. This creates a weakness in the abdominal wall, resulting in a higher risk of herniation, runs the risk of cryptorchidism (failure of testicle descent) which is a risk factor for testicular cancer and places a vulnerable structure outside.
• Despite the fact we don’t need a yolk sac, we still make a vestigial version which can persist into post-uterine life as the Meckel’s diverticulum, a condition that can result in perforation and bleeding.[5]

Any creationist who wants to use ‘elegant design’ as proof of a designer needs to realise that the existence of flawed, incompetent, dangerous design could readily be used to prove that the designer is an incompetent bungler.

Finally, Pearce’s argument is predicated on a deeply flawed understanding of evolution. Evolution refers both to the fact of common descent and large-scale evolutionary chance, and the theoretical mechanism proposed to explain it. The latter is still a subject of active research, but the former is one of the best attested facts in history. Pearce has no excuse for failing to grasp this difference as Darwin on no less than two occasions made this difference explicit. In 1863 he stated that:

Whether the naturalist believes in the views given by Lamarck, or Geoffroy St.-Hilaire, by the author of the ‘Vestiges,’ by Mr. Wallace and myself, or in any other such view, signifies extremely little in comparison with the admission that species have descended from other species and have not been created immutable; for he who admits this as a great truth has a wide field opened to him for further inquiry.[6]

Creationists forget that in The Origin of Species, Darwin assembled evidence for evolution from comparative anatomy, biogeography and embryology, then proposed natural selection as his explanation for how evolution had occurred. He made this explicit in The Descent of Man:

 Some of those who admit the principle of evolution, but reject natural selection, seem to forget, when criticising my book, that I had the above two objects in view; hence if I have erred in giving to natural selection great power, which I am very far from admitting, or in having exaggerated its power, which is in itself probable, I have at least, as I hope, done good service in aiding to overthrow the dogma of separate creations.[7]

While the lack of a robust theory of inheritance meant that Darwin’s theory of natural selection never really gained traction, and in fact fell out of favour from the late 19^th to the early 20^th centuries, the fact of evolution very quickly was accepted by professional biologists as Darwin’s evidence for such change was regarded as compelling. Over the 150 years since then, the case for evolution has become overwhelming. As TR Gregory notes:

Over the past 150 years, [Darwin’s] initial list has been supplemented by countless observations in paleontology, comparative anatomy, developmental biology, molecular biology, and (most recently) comparative genomics, and through direct observations of evolutionary change in both natural and experimental populations. Each of thousands of peer-reviewed articles published every year in scientific journals provides further confirmation (though, as Futuyma…notes, “no biologist today would think of publishing a paper on ‘new evidence for evolution’ ... it simply hasn’t been an issue in scientific circles for more than a century”). Conversely, no reliable observation has ever been found to contradict the general notion of common descent. It should come as no surprise, then, that the scientific community at large has accepted evolutionary descent as a historical reality since Darwin’s time and considers it among the most reliably established and fundamentally important facts in all of science.[8]

Problems – real or imagined – in elucidating how an organ or structure may have evolved do not mean the evidence for common descent from multiple independent fields such as biogeography, palaeontology and comparative genomics go away. This is about as ludicrous as asserting that the failure of general relativity to explain quantum gravity means rocks do not fall when dropped, planets do not orbit their sun and gravitational lensing does not exist. Pearce’s failure to recognise these facts means his book is automatically discredited, as it fails to recognise what evolution really means and why mainstream scientists regard it as a fact. It attacks a straw man version of evolution.

There is however some benefit in picking over the book to expose Pearce's errors of fact and logic, if only to ensure that this book becomes little more than an embarrassing footnote in Christadelphian history.

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[1] Pearce D “Evidence for Design” (2008: The Christadelphian Magazine & Publishing Association Ltd.)

[2] The other is “Creation or Evolution?” by John Hellawell.

[3] A little over ten years after Darwin first published The Origin of Species, W Bennett notes that “The fascinating hypothesis of [descent with modification] has, within the last few years, so completely taken hold of the scientific mind, both in [Great Britain] and in Germany, that almost the whole of our rising men of science may be classed as belonging to this school of thought. Probably since the time of Newton no man has had so great an influence over the development of scientific thought as Mr. Darwin.”  This consensus has remained solid ever since, and nothing has emerged to throw doubt on the fact of common descent and large-scale evolutionary change. See Bennett AW. The theory of natural selection from a mathematical point of view. Nature (1870) 3:30–33.

[4] Marczyk A “Genetic Algorithms and Evolutionary Computation” (2004: TalkOrigins Archive) http://www.talkorigins.org/faqs/genalg/genalg.html Cited 18th January 2014

[5] Mant of these examples are documented in Held, Jr “Quirks of Human Anatomy: An Evo:Devo Look at the Human Body” (2009: Cambridge University Press)

[6] Darwin CR Origin of Species [Letter] Athenaeum. 9 May: 617, 1863

[7] Darwin C. The descent of man, and selection in relation to sex. London: John Murray; 1871.

[8] Gregory TR “Evolution as Fact, Theory and Path” Evo Edu Outreach (2008) 1:46-52

 

 

Why David Pearce's "Evidence for Design" fails to disprove evolution - 2

Pearce’s argument reveals its naiveté in its opening paragraph:

 Science teaching about the natural world invariably assumes acceptance of the theory that organisms changed by an evolutionary process from simple to complex by means of improvements taking place over long periods of time. The idea is so widely accepted that it is rarely challenged. It seems obvious enough in the biology textbook, a progression from microbe to fish, from sea creature to mammal, from fern to flowering plant. Yet looking at the diagram of the evolutionary tree, it is also clear that there are big gaps in the story. (Emphasis mine)[1]

Two things are immediately apparent. The first is his conflation of evolution as fact (reference to evolutionary tree) and evolution as theory (reference to cumulative change over time). Even if the modern synthetic theory was falsified tomorrow, the facts that it explains not only would not go away, but would need to be explained by the successor theory to the MES. Pearce’s failure to properly define evolution in his opening pages undermines the credibility of his attack – he is merely attacking a creationist parody of evolution.

 

The second problem is his belief in the thoroughly outdated idea of progression in evolution, where evolution is seen as a ladder leading from microbe to man at the top. Evolution is not a ladder, but a tree:

 Thinking of evolution as a progression from simple to complex, or ladder-like, furthers the idea that evolution is lineal and that it should be possible to reconstruct a direct line of ancestors. However, the evolution of life, instead of resembling a ladder, is more similar to a branching bush. Darwin’s…contribution to phylogenetic analysis indeed was to introduce the concept of a branching tree of life, with organisms related through common ancestry (Fig. 1). Each branch on the tree represents a distinct lineage; multiple branches can extend from a common point, joined by a set of characters present in the common ancestor; lineages can also acquire characters that are not shared in a common ancestor. Finally, as a result of extinction, not all lineages persist into the future, as can clearly be seen in Fig. 1. Tree-thinking shifts the focus from looking for fossils of lineal (direct) ancestors to looking for synapomorphies that link collateral (side-branch) ancestors. Your grandmother is a lineal ancestor, your great-aunt a collateral ancestor (Fig. 2), but their lives and times were probably not that different…which means that information about one provides information about the other. Paleontologists do not expect to find the direct lineal ancestor of an extant species…nor do they expect to recognize a direct ancestor as “the ancestor” even if they did find it. However, by understanding the lives and times of the species in its family tree, they can understand what its ancestor would have been like.[2]

Fig. 1

The diagram of divergence of taxa presented by Charles Darwin in On the origin of species (1859)

Fig. 2

Sample family tree for an individual (you) showing your collateral (indicated by dashed lines) and direct or lineal (indicated by solid lines) ancestors

Pearce’s opening paragraph completely fails to define his subject properly, and perpetuates the creationist myth of evolution as a progression upwards from ‘simple’ to ‘complex’. In a few lines, he has telegraphed his scientific ignorance, and destroyed whatever chances he had of being taken seriously.
 

Abiogenesis is not Evolution
 

This is sadly not an aberration. In his second paragraph, he employs yet another tired creationist trope, the conflation of evolution with abiogenesis and other separate disciplines:

What about the microbes right at the bottom of the diagram—where did they come from? Cytology, the study of cells, shows that the tiniest microscopic unit of life, once magnified, becomes instantly a whole globe full of intricate specialised parts.[3]

The origin of life is a related but separate discipline known as abiogenesis, and the lack of a universally accepted theory of abiogenesis does not mean that the evidence for common descent somehow is invalidated. Evolution does not explain the origin of life, but the origin of species. Pearce takes his argument to ludicrous extremes by alleging that unsolved problems in atomic physics somehow pose a problem for evolution:
 

How did the microbe evolve? Was it simply by chance combinations of atoms of nitrogen, hydrogen and carbon in the presence of electricity and heat? How did this produce such complexity? And where did the atoms come from? Even an atom, as an elementary physics course makes plain, is itself an ordered world of enormous power, with many component parts—mesons, protons, quarks and electrons, spinning round in tight orbits held in place by charges so strong that, burst apart, the energy released from a few kilograms could flatten a city and destroy a million people. How did all this energy become locked so neatly into the atom?[4]

This is pathetic. I would hardly imagine Pearce would dismiss the fields of inorganic chemistry or metallurgy because he does not know from where the atoms came. Electronics engineers manage to use Maxwell’s equations to design and simulate complex radio frequency devices, despite the fact we don’t know how the electroweak force can be unified with the strong nuclear force. Yet, he thinks our present state of ignorance (or his – one needs to be blunt here) somehow means that common descent suddenly collapses into dust. One hardly needs to take the time to refute Pearce when he does an excellent job of destroying his credibility in his opening paragraphs.
 

His lame parody of abiogenesis, “Was it simply by chance combinations of atoms of nitrogen, hydrogen and carbon in the presence of electricity and heat?” is a particularly egregious example of creationist stupidity. No researcher in abiogenesis thinks that a complex single celled organism magically arose in one step from a chance arrangement of atoms. Pearce’s argument yet again betrays his ignorance of abiogenesis.
 

No scientist denies that abiogenesis is still an area in which many problems exist. There is no universally accepted theory for how the protocell was formed from organic molecules, though many hypotheses have been advanced. Some, such as the “RNA world” model[5] argue that nucleic acids formed first, while others postulate the formation of metabolic pathways first. Stuart Kauffman’s work on autocatalytic sets or the Iron-Sulphur world are two prominent examples of this class of hypothesis. However, unlike evolutionary biology, we do not have a rigorous theory. Eugene Koonan summarises current research in abiogenesis in The Logic of Chance:

 

Despite many interesting results to its credit, when judged by the straightforward criterion of reaching (or even approaching) the ultimate goal, the origin of life field is a failure—we still do not have even a plausible coherent model, let alone a validated scenario, for the emergence of life on Earth. [...]

Not everything is bleak: Major props for the origin of life have been discovered. Certain environments that exist even now, such as networks of inorganic compartments at hydrothermal vents, were likely present 4 billion years ago as well and could be suitable hatcheries for all the earliest steps of the evolution of life, from the synthesis and concentration of monomers to the origin of translation. The RNA World hypothesis that the impressive body of data on the catalytic activities of ribozymes strongly, if not necessarily directly, supports is an attractive - and apparently the only conceivable - way out of the paradoxes associated with the origin of translation.
 

Still, the difficulties remain formidable. For all the effort, we do not currently have coherent and plausible models for the path from simple organic molecules to the first life forms. Most damningly, the powerful mechanisms of biological evolution were not available for all the stages preceding the emergence of replicator systems. Given all these major difficulties, it appears prudent to seriously consider radical alternatives for the origin of life.[6]
 

Present difficulties in a scientific discipline however do not mean that the problem is insoluble, as even a casual glance at the history of science would reveal. Special creationists such as Pearce appear to be uninformed of the recent work in the subject which makes dogmatism on the impossibility of abiogenesis ill-advised. For example. Lincoln and Joyce recently described the self-sustained replication of an RNA enzyme:

 

A long-standing research goal has been to devise a nonbiological system that undergoes replication in a self-sustained manner, brought about by enzymatic machinery that is part of the system being replicated. One way to realize this goal, inspired by the notion of primitive RNA-based life, would be for an RNA enzyme to catalyze the replication of RNA molecules, including the RNA enzyme itself. This has now been achieved in a cross-catalytic system involving two RNA enzymes that catalyze each other's synthesis from a total of four component substrates.[7]

 

Kamioka et al describe the creation of a structure capable of both replicating itself, and catalysing chemical reactions. This is significant for origin of life research, not only because they provide a starting point for creating complex molecules, but because these synthetic replicators have the possibility of mutation. [8]

Then there is the work of Hungarian biologist Tibor Gánti, whose 'chemotron model' provides a compelling model for the simplest system that can be called living.

 

The chemoton (Ganti, 1984). The metabolic subsystem, with intermediates Ai, is an autocatalytic chemical cycle, consuming X as nutrient and producing Y as waste material; pVn is a polymer of n molecules of V', which undergoes template replication; R is a condensation byproduct of this replication, needed to turn r into T, the membranogenic molecule; the symbol Tm represents a bilayer membrane composed of m units made of T molecules. It can be shown that such a system can grow and divide spontaneously. (From John Maynard Smith and Eörs Szathmáry, The Major Transitions in Evolution (1995: OUP), p 21)

Gert Korthof, in a review of Gánti's book 'The Principles of Life' observes:

 

What is the simplest system that still can be called a living system? Plants and animals are composed of cells. Cells are the building blocks of life. So we need to focus on cells. But single cell organisms are still too complex. They can be simplified still further and still be called living. The entity that is stripped of all the unnecessary properties and is still alive is 'minimal life'. Gánti constructed an abstract model that captured minimal life. He called it the Chemoton model. It is composed of 3 subsystems:

 

1. Chemical motor system: A soft chemical self-reproducing system capable of synthesising chemical substances for itself as well as for the other two systems [metabolism. Example: proteins ]

2. Chemical boundary system: a soft chemical system which is capable of spatial separation, of being selectively permeable to chemical substances, and of growth in the presence of its raw materials [ membrane. Example: lipids ]

3. Chemical information system: a chemical system which is capable of self-reproduction in the presence of the appropriate raw materials [information. Example: RNA/DNA ]

Note: the 3 components superficially look like the three parts of the prokaryotic or eukaryotic cell: cytoplasm, membrane, nucleus. However, the chemoton model is not a model of the prokaryotic or eukaryotic cell, but a very general model for life; the simplest possible life.

 

The chemoton model does not contain enzymes (catalysts). It is a metabolism without enzymes. Since there are no enzymes, there is no need for the genetic code. This simplifies the chemoton model significantly. "Gánti liberated himself from the burden of the genetic code" says Szathmáry.

The chemoton model fulfils the 5 absolute life criteria. The chemoton is a unit, because deleting one of its subsystems reduces it to a chemical system. The chemical motor is equivalent with metabolism. The chemical motor is inherently stable (described in the book). The fourth criterion is fulfilled by the information carrying subsystem and the program control is present in the chemoton (described in the book). [9]

 

The point of citing Gánti’s chemotron model is not to argue that this is what the earliest living cell would have looked like, but to point out that origin of life researchers do not think that the first form of life was not a complex cell, and did not form magically. Gánti’s chemotron model shows the level of simplicity that origin of life researchers postulate, and these are considerably more simple than obligate intracellular bacteria such as the Rickettsia.

 

Conspicuously absent are references to experiments designed to shed light on abiogenesis such as Nobel Laureate Jack Szostak, who is one of the leading origin of life experts. Recently, Szostak announced the creation of a plausible prebiotic protocell in which nonenzymatic RNA copying could take place:

 

Efforts to recreate a prebiotically plausible protocell, in which RNA replication occurs within a fatty acid vesicle, have been stalled by the destabilizing effect of Mg2+ on fatty acid membranes. Here we report that the presence of citrate protects fatty acid membranes from the disruptive effects of high Mg2+ ion concentrations while allowing RNA copying to proceed, while also protecting single-stranded RNA from Mg2+-catalyzed degradation. This combination of properties has allowed us to demonstrate the chemical copying of RNA templates inside fatty acid vesicles, which in turn allows for an increase in copying efficiency by bathing the vesicles in a continuously refreshed solution of activated nucleotides.[10]
In just five paragraphs, Peace has:
 

1. Failed to properly define evolution

2. Failed to differentiate between evolution as fact and evolution as theory

3. Failed to recognise that the idea of progression alone a ladder is a parody of evolution which is best modelled as a tree

4. Conflated evolution and abiogenesis, and implied that unsolved problems in completely unrelated fields such as nuclear physics somehow pose a probem for evolution. 

Blunders of this magnitude so early in a book destroy his credibility. There is no way to avoid this fact.

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[1] Pearce D “Evidence for Design” p 3

[2] Mead LS “Transforming our Thinking about Transitional Forms” Evo Edu Outreach (2009) 2:310-314

[3] Pearce, op cit p 3

[4] ibid, p 8

[5] Cech T.R. The RNA Worlds in Context (2011) Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a006742

[6] Koonin E.V "The Logic of Chance: The Nature and Origin of Biological Evolution" (2011 FT Press)

[7] Lincoln T.A., Joyce G.R Self-Sustained Replication of an RNA Enzyme Science (2009) 323 (5918): 1229-1232

[8] Kamioka S et al “Autocatalysis and organocatalysis with synthetic structures” Proc. Natl. Acad. Sci. USA 12 January 2010: 541-544.

[9] Korthof G Review: "The Principles of Life" 29th Dec 2003 (updated 19th July 2013)

[10] Adamala K, Szostak JW  Nonenzymatic Template-Directed RNA Synthesis Inside Model Protocells Science (2013) 342:1098-1100