Icons of Human Evolution

Jonathan Wells' book Icons of Evolution argues that many of the most commonly accepted arguments for the validity of evolution are invalid. Wells tackles the topic of human evolution in Chapter 11, "From Ape to Human: The Ultimate Icon".

The title is doubtless a reference to the "March of Progress", one of the most recognisable visual images in our culture. This famous drawing shows a sequence of primates walking from left to right, starting with a small knuckle-walking ape on the left, progressing through a series of apemen, and finishing with a modern Cro-Magnon male on the right. The original version of this was published in the Time-Life book Early Man in 1970 and was drawn by Rudy Zallinger, but since then it has been endlessly copied, modified, and parodied. In fact, a version of this drawing adorns the cover of Wells' own book, and Wells describes it as the "ultimate icon" of evolution.

On the web site set up to publicize Wells' book (http://www.iconsofevolution.com/), Wells says:

When asked to list the evidence for Darwinian evolution, most people--including most biologists--give the same set of examples, because all of them learned biology from the same few textbooks. The most common examples are:

[other list items omitted...]

drawings of ape-like creatures evolving into humans, showing that we are just animals and that our existence is merely a by-product of purposeless natural causes.

Well's Chapter 11 consists largely of a collation of all the material he can find which stresses the uncertainty and unknowns in the study of human evolution. There are discussions about the Piltdown fraud (what creationist book would be complete without one?), whether paleoanthropology is science or myth, what the fossils can show us, etc., all illustrated with quotes from scientists.

Wells' analysis of Thomas Huxley's 1863 book Evidence as to Man's Place in Nature points out that as there was no fossil evidence for human evolution known at the time, Huxley compared human to ape skeletons to show their close similarity. It's hard to see anything particularly offensive about this, but for Wells "What Huxley's illustration shows is that, from the very beginning, the ape-to-human icon was simply a restatement of materialistic philosophy".

Wells, like many creationists, obviously seems to believe that evolution is a "materialistic philosophy". But evolution, like any scientific theory, merely tries to find natural explanations for the natural world. Whether one chooses to believe that "our existence is merely a by-product of purposeless natural causes" is up to the religious beliefs of the individual. It is certainly not implied by evolution, as should be obvious from the fact that many scientists are theists.

The section discussing Huxley is entitled Finding evidence to fit the theory. Again, it's hard to see what the problem is with this, since scientists are meant to find evidence for their theories.

At the time of the discovery of Piltdown Man (1912), Wells says that there was no evidence for human evolution, as the status of Eugene Dubois' Java Man fossil as an ape/human intermediate was widely disputed. That's not exactly true. Dubois' precise interpretation was widely disputed, but as Marcellin Boule pointed out in his 1923 book Fossil Man,

These differences of opinion are more apparent than real. Those who believe in the simian character of Pithecanthropus really look upon it as an ape superior to all living apes, and those who believe in its human character regard it as inferior to all known men, living or fossil. Wherever we place the Trinil fossil, according to its morphological characters, in the series between Ape and Man, as at: P, P', P'',

Ape.......P........P'........P''........Man

The fact remains that in all its characters known to us, this fossil stands in an intermediate, or if terminological exactitude be preferred, an interposed, position. This is a positive fact admitted to by all competent naturalists.

Boule's judgement is still valid, except that with the benefit of much more study and fossil evidence, modern scientists can now attribute Java Man to the species Homo erectus, and would place it in the P'' position in Boule's series (i.e. intermediate, but closer to humans than to apes). This fossil is just one example of a considerable amount of fossil evidence that Wells ignores.

One writer quoted by Wells is Henry Gee, an editor of the scientific journal Nature, regarding the difficulties in reconstructing ancestor/descendent lineages given the fragmentary nature of the fossil record and the long periods of time involved. Gee has complained that Wells' selective quoting misrepresents his views. While he has indeed argued that some scientists are guilty of story-telling and constructing scenarios that go beyond what can be supported by the fossil evidence, Gee points out that this does not mean that fossils exhibiting transitional structures do not exist, nor that it is impossible to reconstruct what happened in evolution.

Wells also quotes Gee as saying that all the evidence for human evolution "between about 10 and 5 million years ago - several thousand generations of living creatures - can be fitted into a small box". True enough, but there is far more evidence for the more relevant 0-5 million year range, which is when almost all of human evolution occurred. It's a vivid illustration of how Wells is interested only in focusing on where the evidence is missing, and never where it's present.

As an example of the unreliability of artists' impressions, Wells mentions the March 2000 edition of National Geographic, which showed drawings from four artists based on the same set of bones. After describing the considerable differences between them, Wells adds:

"Not surprisingly, the strongly pro-Darwin National Geographic buried these revealing drawings on an unnumbered page among the advertisements at the back of the magazine."

Come on, let's be serious. If you want to hide something, you don't publish it in a magazine with worldwide distribution of over 8 million copies per month, not even in the back pages. It was in the back pages for precisely the reason stated by NG: they were giving readers a preview of an upcoming project.

OK, let's accept that artistic reconstructions are of doubtful accuracy. So what? Scientists certainly don't depend on such reconstructions to do their studies, and they are hopefully never used as evidence even in textbooks, but merely as illustration. I fail to see why this is any more reprehensible than the pictures of dinosaurs that are ubiquitous in our culture, and which also involve considerable guesswork.

Wells also mentions the case of the fossil skull ER 1470, the appearance of which differs depending on the angle at which one chooses to connect the face to the rest of the skull. It seems Wells is only ever interested in dwelling on the ambiguities, and not on what can be determined from this or other fossils. In the case of 1470, for example, we can tell that the braincase is much larger and more modern-looking than that of any ape, but still much smaller than all but the most pathological of modern humans.

A section entitled "What DO we know about human origins?" discusses various controversies about Neandertals, the Out-Of-Africa/Multiregionalism debate, and the lack of a consensus or an encompassing theory among scientists about human origins. Wells' statement that

"The general public is rarely informed of the deep-seated uncertainty about human origins that is reflected in these statements by scientific experts. Instead, we are simply fed the latest version of somebody's theory, without being told that paleoanthropologists themselves cannot agree over it"

is quite a stretch, given that debates over these topics have been widely covered in the popular media. (In fact, the media seems to delight in reporting the often fierce debates on human origins.) As usual, Wells' arguments demonstrate that we don't know everything about human evolution (true), while trying to leave the impression that we don't know anything about it (false).

In the final section of his chapter, entitled Concepts masquerading as neutral descriptions of nature, Wells quotes Michael Ruse, a well-known philosopher of science and an ardent evolutionist, as saying:

"If people want to make a religion of evolution, that is their business," Ruse wrote, but "we should recognize when people are going beyond the strict science, moving into moral and social claims, thinking of their theory as an all-embracing world picture. All too often, there is a slide from science to something more."

Ruse objects when, in his words, "evolution is promoted by its practitioners as more than mere science. Evolution is promulgated as an ideology, a secular religion." Ruse argues, and I agree, that anyone who does this should be careful to distinguish between science, and philosophical viewpoints based on science. That does not mean, of course, that evolution itself is not scientific, and Ruse is emphatic that it is.

Naturally, Wells agrees that such philosophical viewpoints should not be taught as if they were science. This does not, however, have much to do with how evolution, and specifically human evolution, is currently taught in textbooks. The only example of such misuse which Wells gives is a biology textbook (Biology, Raven and Johnson 1999) which has this quote from an interview with biologist Stephen Jay Gould:

"Humans represent just one tiny, largely fortuitous, and late-arising twig on the enormously arborescent bush of life."

I assume it is the phrase "largely fortuitous" that Wells objects to. Arguably, this opinion is more philosophical than scientific (though it's also arguable that it isn't). Still, one phrase in one quote in an interview that is peripheral to the main text hardly seems worth getting overexcited about. It doesn't mean that the treatment of evolution, or of human evolution, in that textbook is not accurate. And it certainly doesn't mean that Wells is justified in tarring the whole science of human evolution with his final comment that "this is not science, but myth".

Given that the subtitle of Icons of Evolution is "Why much of what we teach about evolution is wrong", one might naturally expect that his Chapter 11 would be largely devoted to discussing the currently accepted evidence for human evolution, and showing why it is invalid. The most stunning aspect about Chapter 11 is that there is no such discussion! The fossil evidence is almost totally ignored (even though Wells felt that there was room for a couple of pages on the Piltdown fraud, which is utterly irrelevant to the modern study of human origins).

As a creationist, Wells presumably does not believe humans evolved, but you'd be hard put to discover it from this chapter. Wells does not dispute any of the currently accepted fossil evidence, and even admits that:

"Many fossils have been found that appear to be genuine, and many of them have some features that are ape-like and some that are human-like."

Let's give credit where it is due: it's not often you'll see a statement as honest as that in creationist literature.

If textbook accounts of human evolution are as biased and subjective as Wells seems to think, surely the solution is to remove the bias. However, Wells does not actually present any examples of bias in textbook accounts of human evolution. The website blurb for Well's book (quoted above) implies that textbooks present the "March of Progress" image as evidence for human evolution, but Wells does not give any examples of textbooks which even print the image, let alone use it as evidence that humans evolved or that "our existence is merely a by-product of purposeless natural causes" [1]. I too would hope that textbooks would not use the March of Progress image as evidence, primarily because a speculative drawing is not evidence (I can agree with Wells on that much). Using an image as evidence would be doubly foolish when there is so much real fossil evidence available.

What is the fossil evidence which Wells seems so reluctant to discuss?

There are many australopithecine fossils, belonging to many different species. The brain sizes are apelike, but most of them were bipedal.
Homo habilis fossils are similar to the australopithecines in many ways, but also contain features linking them to humans
Homo erectus (Java Man, Peking Man, Turkana Boy, etc.) These fossils date from about 1.9 million to 300,000 years in age. The body was fully adapted to bipedalism, and very similar to that of modern humans, though more robust. The skull, however, is recognizably different from modern humans, with large brow ridges, large jaws, and small brains ranging from about 750 cc to 1225 cc.
Other fossils, variously classified as Homo heidelbergensis or archaic Homo sapiens, are intermediate in both time and morphology between Homo erectus and modern Homo sapiens (e.g. Heidelberg, Kabwe, Petralona).

Listing examples of bias and error or quotes from scientists pointing out areas of uncertainty is all well and good, but what, precisely, is Wells' beef with the real evidence? We never find this out. Presumably Wells is unhappy with the way human evolution is currently taught, but it is not at all obvious what changes he would like made, or how the fossil evidence can be explained without invoking some theory of human evolution. One can agree with Wells that bias and subjectivity have played a role in the study of human evolution (and doubtless continue to do so), but the situation seems nowhere near so bleak as Wells paints it.

Though he avoids explicitly saying it, one gets the impression that Wells' preferred solution would be to remove all mention of human evolution from textbooks on the grounds that it is all too hopelessly speculative. But if there is real evidence, as Wells himself admits is the case, surely the best course is to present that evidence as accurately as we can. If Wells has specific examples of bias or error in treatments of human evolution, or suggestions for improvements, then he should present them. The fact that Wells did not do so makes me suspect that most textbooks treat human evolution fairly accurately.

In summary, this chapter of Wells' book is totally underwhelming. Before reading the chapter, I expected there would be some of the usual creationist arguments against human evolution to rebut, but it turned out there was virtually nothing that needs rebutting. Although Wells' book supposedly refutes the iconic examples of evidence for evolution, in the case of human evolution Wells does not even shake the evidence, let alone overturn it. Astonishingly, Wells does not even attempt to discredit any of the currently accepted evidence for human evolution [2]. It seems as though the evidence for human evolution was too strong for Wells to wish to attack it head on and that he instead had to resort to undermining it. The science of human evolution must be in fairly good shape if this chapter is the best attack that Wells can muster against it.

Footnotes

1. The National Center for Science Education, in a rebuttal of Wells' book, disputed Wells' web site claim about "drawings of ape-like creatures evolving into humans, showing that we are just animals and that our existence is merely a by-product of purposeless natural causes". They responded:

The notion that such drawings [of ape-men] are used to "justify materialistic claims" is ludicrous and not borne out by an examination of textbook treatments of human evolution. (NCSE, 2001)

In response, Wells lists three textbooks that say things such as: living things have developed "just by chance", "by a roll of the cosmic dice", "evolution works without plan or purpose", and "evolution is not directed toward a final goal or state". And, Wells adds,

"all three of these textbooks include fanciful drawings of ape-like humans that help to convince students we are no exception to the rule of purposelessness"

In other words, Wells was unable to produce any evidence that drawings of "ape-men" are being used to teach students that "our existence is merely a by-product of purposeless natural causes". The quoted statements have no particular connection to the ape-men illustrations, other than coming from the same books. And even the quoted statements like "evolution works without plan or purpose", and "evolution is not directed toward a final goal or state" are not necessarily materialistic. They don't preclude the possibility of a god who may have chosen to use or subvert evolution according to his design, but any such design is not part of the evolutionary process; it is imposed from outside evolution, and does not and should not form part of evolutionary theory.

These statements don't deny the possibility of God; they merely refuse to advocate God's existence, as Wells apparently thinks they should. But such advocacy would be a religious opinion, not a scientific one, and should rightly be excluded from textbooks. Return to text

2. I am not the only reviewer to notice the extraordinary feebleness of Wells' attack on human evolution. From Jerry Coyne's review of Icons of Evolution in Nature:

When discussing other 'icons', Wells uses the same tactic of selective omission to distort a body of literature he pretends to review. Nowhere is this more visible than in his chapter on human evolution. Faced with a series of hominid fossils showing transitions from ape-like to modern human traits over 4 million years, Wells can only mumble about the Piltdown Man hoax, and imply that the vigorous scientific debate about the course of human evolution proves that humans did not evolve.

Larry Martin, in another review, had this comment:

While we are talking about fossils, what about the human story? What are australopithecines if not the bones of primitive humans? Why do we not find modern humans with them? Wells seems to accept the fossil evidence at face value and contents himself with pointing out the confusion over Neanderthals when they were first discovered, or how reconstructions vary over how human an australopithecine might have looked in life. He seems genuinely uncomfortable about what we should do with these lowbrow cousins and microcephalic uncles attached to our family tree. Should they be locked away in the cellar so schoolchildren will not see them? He hits his stride with Piltdown Man, a deliberate fake, but his attempt to resolve the human story into petty wrangling over a few old bones cannot change the broad outline of human evolution, which remains intact using evidence that he allows.

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This page is part of the Fossil Hominids FAQ at the talk.origins Archive.