The Accidental Species: Misunderstandings of Human Evolution

by Henry Gee

  All of which areological digression leads me very conveniently to another remarkable ability of humans—that of telling stories. Chains of unconnected craters became lines which became canals which became, implicitly, a heroic narrative of a great civilization struggling against extinction—and, more explicitly, thrilling yarns of interplanetary warfare and high adventure.

  So, not only are we good at spotting patterns, even if nonexistent ones, we tend to weave them into tales as ways of making sense of what might otherwise be sets of disconnected and therefore worrying phenomena. This ability is so ingrained that it even haunts our subconscious. Things that go bump in the night are seamlessly woven into the stories we tell ourselves in dreams. It is easy to see how our ancestors, living much closer to nature, the unknown, and the reality of sudden and unexplained phenomena than we do nowadays, would hear thunder in the mountains and console themselves with stories of angry gods. And because telling stories is what we do, even without conscious intervention, it’s easy to underestimate how the power of narrative undermines our efforts to make sense of the past, in any clear, cool, or rational way.

  Fossils present direct evidence of the prehistoric past and for evolutionary change, but they are very thin gruel on which to build a narrative—rather like the dots of individual craters that Schiaparelli and Lowell willed into line segments, canals, and stories. This has not stopped people doing that very thing, but if they do, they must be aware that such a narrative is very likely to be colored as much by past prejudices as by present evidence. Fossils don’t tell stories. We tell stories.

  And so, in popular science books, particularly older ones, you’ll hear tales of the ages of life—the Age of Fishes, the Age of Amphibians, the Age of Reptiles, the Age of Mammals, just as if they were biblical dynasties, one succeeding the other, replacing the one before—inevitable, seamless, majestic, culminating in the Age of Man.

  One of my favorite examples of this tendency is indeed called The Age of Reptiles. This is a marvelous 110-foot mural at the Peabody Museum of Natural History at Yale, painted in 1947 by Rudolph F. Zallinger. It depicts almost 350 million years of prehistory as a landscape, with time moving from left to right. This image—and the various dinosaurs and other animals pictured within it—has become iconic.

  Even before I knew what a dinosaur was, I knew of Zallinger’s work. For my fifth birthday I was given a book called Wonders of Nature, whose back cover was adorned with a kind of condensed version of The Age of Reptiles. I still have the book (I’m looking at it as I write this), and there is no indication of what the animals on the back cover were—no caption, no acknowledgment, no nothing. But I was captivated, nonetheless.

  A little later when I was at school, I loved the Life Nature Library, a series of color primers on science brought out by Time-Life. It was in the book called Early Man (1965) that I first came across the now canonical image of human ancestry, depicted as a left-to-right “march” of ancestry and descent, the conceptual progenitor of my figures 1 and 2 earlier in this book, and of many others. The picture was called The March of Progress and was painted—hey, you’re way ahead of me—by Rudolph Zallinger. I do not think Zallinger had any intention to mislead. He did not, after all, draw arrows between the various reconstructed hominins. But his images have the power they do because they trigger our innate desire for narrative. Once we see them, we cannot help but put arrows between the images and think of them as ancestors and descendants.

  In this book, therefore, I have as much hope of curing you of a perfectly natural desire to make stories out of disconnected dots as persuading the tide to turn at my command. All I can do is show you how very hard it is, in reality, to justify evolutionary narratives created from fossil evidence; invite you to wonder why it is that you create the stories you do; ask you to inquire how your status as a human being colors your view (quite naturally) of what you think ought to have happened; and, once that has been accounted for, imagine what other stories might be possible given the evidence at hand.

  What would our picture of human evolution be like had we evidence of many more kinds of fossil hominin living into the recent past, or fewer; or had we persuasive evidence of nonhuman hominins living on this planet today?

  The irony is that—I guess—our picture of evolution would be very similar to the one we have now. Such are our prejudices about progress; such is our overwhelming need to tell stories, that we’d have spun a tale of upward progress and improvement, culminating in Man, no matter whether we had ten times the fossils we have now, or none, and irrespective of the provenance or the poverty of the ingredients.

  At this point I should add a few cautionary paragraphs. I made similar points in my book In Search of Deep Time (1999), but my words continue to be misconstrued more than a decade later—quite willfully and deliberately, and with intention to deceive. The culprits have been creationists, who quote extensively from In Search of Deep Time in support of their view that evolution is somehow “wrong,” such that even a “prominent evolutionary biologist” such as myself “admits” this. Despite repeated attempts to expose creationists for such context-free quote-mining, the creationists are still at it.

  Perhaps the most shameful activity in which creationists indulge is to present a distorted version of science to parishioners who might not know any better. A few years ago an elderly neighbor came up to Mrs. Gee in the street and gave her a pamphlet that she thought might be interesting, as it mentioned me. I sighed—it was Christian literature in which my various utterances on evolution had been quote-mined in support of creationism. Readers in the United States, who are more used to this sort of thing, will be either comforted or disturbed to learn that creationism runs deep in mainstream English churchgoers, not to mention synagoguegoers and mosquegoers.

  It is quite true that I have said quite a few grandstanding things about evolution, and if taken out of context, you can see why they fill creationists with glee. Here is a choice selection from In Search of Deep Time, extracted and presented out of context by a creationist website,1 with responses by me.

  The intervals of time that separate fossils are so huge that we cannot say anything definite about their possible connection through ancestry and descent.

  Leaving aside the assertion by some creationists that no such intervals of time exist, the creationist spin is that no connection exists between ancestors and descendants, because of the unsupported presumption that God made everything separately. The proper answer (made clear elsewhere) is that ancestors and descendants exist—the community of all life is evidence for this—but we could never know that any fossil we find is an ancestor or descendant or anything else. Quite apart from anything else, the concept of Darwinian evolution is more elegant as a theory than anything offered by creationism, because it explains the community of all life without recourse to any other factors, whether they are Lamarckian besoin, Goethean cosmic strivings, or God.

  New fossil discoveries are fitted into this preexisting story. We call these new discoveries “missing links,” as if the chain of ancestry and descent were a real object for our contemplation, and not what it really is: a completely human invention created after the fact, shaped to accord with human prejudices. In reality, the physical record of human evolution is more modest. Each fossil represents an isolated point, with no knowable connection to any other given fossil, and all float around in an overwhelming sea of gaps.

  Dinosaurs are fossils, and, like all fossils, they are isolated tableaux illuminating the measureless corridor of Deep Time. To recall what I said in chapter 1, no fossil is buried with its birth certificate. That, and the scarcity of fossils, means that it is effectively impossible to link fossils into chains of cause and effect in any valid way, whether we are talking about the extinction of the dinosaurs, or chains of ancestry and descent. Everything we think we know about the causal relations of events in Deep Time has been invented by us, after the fact.

  To take a line of fossils and claim that they re
present a lineage is not a scientific hypothesis that can be tested, but an assertion that carries the same validity as a bedtime story—amusing, perhaps even instructive, but not scientific.

  The chain of ancestry and descent we construct after the fact is just that—a human construction, a way of interpreting the evidence. However, this does not negate the existence of evolutionary ancestry and descent. I suspect creationists are sometimes motivated by the suggestion that when evolutionary biologists are in company, away from the public eye, they “admit” that evolution is wrong, while perpetuating some enormous cover-up to set before the masses. One shouldn’t like to say in print that this is paranoid, but any suspicion of such a cover-up is immediately scotched by the fact that many books making these points are widely available to the public. In Search of Deep Time was hardly a massive best seller—but it wasn’t some dark secret either, the existence of which could only be vouchsafed to the Elect.

  All the evidence for the hominid lineage between about 10 and 5 million years ago—several thousand generations of living creatures—can be fitted into a small box.

  To which we say—so what? This illustrates the extreme poverty of the fossil record, offering a caution to anyone who would use this evidence on which to base an evolutionary scenario. It doesn’t dent evolution in any way.

  Creationists quote material out of context to give you the misleading impression that anyone has any doubt about evolution’s status as a theory so well worn that it can be accepted as true. I hold that view now, just as I did more than ten years ago when I wrote In Search of Deep Time—and in that book, too, I made my views clear, except that creationists have chosen not to mention them. “If it is fair to assume that all life on Earth shares a common evolutionary origin,” I wrote on page 5, going on to make clear that this is my assumption throughout the book. Creationists are very good at either ignoring such statements—or, if they mention them, say words to the effect that if even “prominent evolutionists” who explicitly sign up to the fact of evolution can produce statements in which evolution is doubted, there shouldn’t be any reason for anyone else to “believe” in evolution, either. And they just keep rolling along: enter “Henry Gee” and “creationism” into a search engine of your choice, and they’ll be all over you like an embarrassing rash. That said, I have had some robust and heartening support.2

  The sad thing is that no matter how hard I fight, the creationists will still take quotes out of context, because that’s the way they do what they call “science.” Like all pseudoscientists and peddlers of charlatanry, they don’t investigate anything systematically. They just pick out the things they like and discard anything else, even flat statements to the contrary. Now, I could try quoting scripture out of context to show how such a procedure can be used to mislead. For example, “There is no God.”3 But that approach might be too subtle. That said, I refuse to modify my thoughts for fear of being quote-mined by idiots. I tend to regard creationists as an occupational hazard, rather in the same way that those who go walking in the dark, looking up at the stars, will occasionally tread in a pile of dog shit.

  In the end, one can only feel a kind of pity for creationists. Many believe in the literal truth of Genesis, despite the fact that the Bible was written at various times by different hands, and despite the fact that the text has been translated into English from classical Hebrew, a language so tricky that people of formidable learning, such as St. Jerome, Thomas Aquinas, Rashi, and Maimonides, spent their lives trying to understand its nuances in order to extract meaning from the same scriptures to which many people of perhaps lesser intellects cleave without question. Those living in medieval times had perhaps no good reason to doubt the literal truth of the Bible. People living today do not have this excuse.

  Evolution itself, however, is not in question.

  Evolution happened, and there is, out there, a true skein of ancestry and descent between some primordial blob and every creature living or extinct, but we can never trace it with absolute certainty, or if we stumble across part of it, we can never know that we have done so.

  What is in question, however, are the ways we interpret the evidence given to us by fossils. It’s not that fossils don’t provide us with primary evidence for evolution as a fact, because they plainly do so. What is at stake is a common misreading of evolution that flatters our prejudices: that we are the pinnacle of creation, and the various stages toward this manifest destiny can and should be discernible in the fossil record. The picture of a simple, linear evolution, with each species of human being succeeded by a more sophisticated form, “culminating in Man,” can only be extremely inaccurate, and also misleading.

  Although it’s fun to take potshots at creationist misbehavior, it is perhaps worth asking why creationists remain indefatigable despite the evidence, devoting such time and effort and skill to monitoring the writings of “evolutionists” and extracting such morsels that suit them. When you take a step back, you can see that we have seen this mindset elsewhere, among those scientists who look into the unknown and see a set of circumstances that dashes the more comforting scenarios on which they have perhaps based their reputations. I think that what motivates creationists and such scientists is a very human fear of the unknown, and the uncertainty that accompanies it.

  The fundamental difference between religion and science is that the former is all about the celebration of certainty, whereas the latter is all about the quantification of doubt. Creationists understand this instinctively. What they cannot afford to see happen is that people start wondering about their place in the universe, and asking whether the certainties in which they have been raised might not be so certain after all. They are so desperate to avoid this that they have tried to subvert science by invoking a bogus replacement called “creation science,” perhaps the most shocking oxymoron ever invented, given that creationism and science concern such fundamentally different things.

  Scientists have been less ready to appreciate this distinction, to their cost. When confronted by creationists, they are inclined to close ranks and present a united front of “fact” against “mythology.” Such a strategy only plays into the creationists’ hands, leaving them free to mine the works of evolutionary biologists for quotes—the subtext being that scientists are always squabbling behind the scenes, and the united front they want you good honest folks to believe is a cover-up.

  In my view the best way that scientists can confront creationism is to be as honest as possible. Science is not all about truth given to us by authority, but doubts that arise from the ground up. You, the citizen, should never be afraid to ask a silly question—and you, the scientist, should never be afraid to admit that you don’t know the answers.

  So much for the fossils. What of humans living today? What actually defines a human being, so that you can tell one apart from, say, a postbox, or the back end of a cow? What is Man, if no longer the microcosm that measures the macrocosm? To quote scripture again, “What is man, that thou art mindful of him?” (Psalms 8:4).

  My task in the rest of this book is to show that this question is meaningless. Were one to accept the argument I put forward in chapters 2–5 of this book, the very idea of a distinctive nature of humanity is already questionable. Once one acknowledges that the ladder of creation with Homo sapiens at the top is the result of a fundamental misreading of evolution, you can see that when viewed objectively, we humans are no more or less deserving of special consideration than any other species. There is certainly nothing so special about humanness—as opposed to hamsterness or geraniumness—that demands the elevation of humans to a higher order of being.

  Those of a certain turn of mind or upbringing will no doubt balk at this, saying that humans are different from other animals (and plants, and bacteria, and fungi, and so on) because they have an immortal soul. It’s hard to argue against convictions founded on belief rather than empirical evidence, except to counter that each and every species has attributes that allow us to recognize it as
such. The Madagascar star orchid, for example, is recognizable by the extraordinarily long floral spurs of its flowers, penetrable only by the very long tongues of a particular species of moth. Such features can be identified and quantified, which cannot be done for the soul, begging the question of the existence of such an attribute.

  Even if we leave such imponderables as the existence of the soul to theologians and philosophers, we run into another problem: it’s very hard to define what we think is special about humanity because it’s we, the humans, who are composing the definitions. Objectivity is impossible. The validity as such of any we recognize in ourselves is compromised by an unavoidable subjectivity. Were we all Madagascar star orchids, we would no doubt measure our exalted state by the lengths of our floral spurs relative to those of other orchids.

  In the rest of this book, I take a brief tour of several attributes that at some time or another have been regarded as unique to humans. These include bipedality, technology, intelligence, language, and finally sentience or self-awareness. It turns out that most if not all have been seen in one or more nonhuman species—or once one has accounted for a human bias in investigating such attributes, they turn out to be no more special than any other feature of any other organism.

  The order in which I examine these attributes is not random, but dictated by how easily we can find actual biological evidence for the evolution of these traits.

  Bipedality, for example, can be assessed directly, by looking at fossil bones. We can judge by direct inspection whether a given fossil creature habitually walked on its hind legs, or not. So much so that bipedality is seen as a hallmark of the hominins. A fossil ape is marked as belonging to the hominins if it is bipedal, almost without reference to any other feature. From this is would be easy to imbue the acquisition of bipedality as something special, the first step (pun intended) in the inevitable journey to the human state, as if technology, language, intelligence, and so on would surely follow. Bipedality, however, is just one peculiar posture adopted in a group of animals in which the adoption of peculiar postures is commonplace. Human bipedality is a posture seen nowhere else—but one could say the same for knuckle walking in chimps and gorillas, brachiation in gibbons, and the four-handed swing of orangutans. Furthermore, there have been one or two fossil apes, unrelated to hominins, that were more or less bipedal, and their fate was extinction without achieving technology, language, and so on (as far as we know).