What Can We Responsibly Believe About Human Evolution?
We've been looking at the recent Flores man find (not really a "new species") and the gradual reassessment of the Neanderthals as not very different from us either physically or mentally. Human evolution studies seem to have reluctantly absorbed this change in view, though popular culture may lag.
"In the minds of the European anthropologists who first studied them, Neanderthals were the embodiment of primitive humans, subhumans if you will," noted Fred H. Smith, a physical anthropologist at Loyola University in Chicago in 2003. But "The evidence for cognitive inferiority is simply not there," says Paolo Villa, a curator at the University of Colorado Museum of Natural History in 2014. "What we are saying is that the conventional view of Neanderthals is not true."
Villa and colleague Wil Roebroeks carefully studied explanations for the extinction of the Neanderthals as a separate human group based on the assumption that they were inferior. Such hypotheses include the idea that they did not use complex, symbolic communication, were less efficient hunters, had inferior weapons, or were not omnivorous. As we have seen, none of these hypotheses panned out.
In any event, the current human genome incorporates Neanderthal genes; it's at least possible that they were just assimilated, the way many tribes in millennia past were assimilated into larger groupings, empires, or nation states, and lost their separate identity. One question the new assessments raise is, was there ever more than one human race?
And, in any event, what do we really know about our past? A 2012 article in Scientific American acknowledged, with good reason as we have seen, "The origin of our genus, Homo, is one of the biggest mysteries facing scholars of human evolution." Intriguing finds lead to a barrage of conflicting narratives, partial and uncertain, much like ancient mythologies.
And the field has experienced fraud as well as dissension. Consider Piltdown man ("archaeology's greatest hoax"). The pretended fossil (which "turned up" in 1912 and was not exposed as a composite until 1953) was a simple, easily detectible fraud that went undetected because it was so valued by British paleontologists that for over forty years they would neither consider it closely nor permit anyone else to do so. Over thirty suspects, including prominent scientists, have been suggested as the possible fraudster:
Charles Dawson, the archaeological enthusiast who found the first pieces, was almost certainly involved. But many scientists still suspect he had the backing of experts who were the true guilty parties. Candidates include Arthur Conan Doyle, who played golf at Piltdown and had a grievance against scientists because of his spiritual beliefs; the Jesuit philosopher, palaeontologist and alleged practical joker Pierre Teilhard de Chardin, who lived in Sussex at the time and who actually helped Dawson dig at Piltdown; Arthur Smith Woodward, the Natural History Museum scientist, who accepted Dawson's finds as genuine and argued they belonged to a new species of early human; the anatomist Arthur Keith, who also passionately endorsed the discovery; and Martin Hinton, another museum scientist, whose initials were found, in the mid-70s, 10 years after his death, on an old canvas travelling trunk, hidden in a museum loft, that contained mammal teeth and bones stained and carved in the manner of the Piltdown fossils. When it comes to suspects, the Piltdown Hoax makes Midsomer Murders look restrained.
Piltdown mainly demonstrates how deeply committed the generations of fossil hunters after Darwin have been to the story of the "ascent of man" he so effectively popularized.
And then there are the vendettas. Svante Paabo, a Neanderthal genome researcher, has struggled to understand the spite that mars human paleontology, in contrast to his experience in his specialty of molecular biology:
I suppose the reason is that paleontology is a rather data-poor science. There are probably more paleontologists than there are important fossils in the world. To make a name for yourself is to find a new interpretation for those fossils that are extant. This always goes against some earlier person's interpretation, who will not like it very much. ... It's almost like social anthropology or politics -- you can only win by somehow yelling louder than the other person or sounding more convincing.
Now and then, we discern a meaningful thread in the narrative, but it generally leads away from Darwin and his followers. Here are some significant overarching problems with the typical consensus science accounts we are urged to accept, summarized:
Basic outlines of our origins are admitted to be uncertain and conflicting: In PNAS, paleobiologist Bernard Wood puts it like this:
The origin of our own genus remains frustratingly unclear. Although many of my colleagues are agreed regarding the "what" with respect to Homo, there is no consensus as to the "how" and "when" questions.
Similarly, physical anthropologist John Hawks, no friend of design as an explanation of human origins, has called the circular dating processes often used "the genetic equivalent of money laundering!"
The evolution of consciousness is presently inexplicable: Can we really understand a transition from the excrement-throwing ape to the early cave paintings as a long, slow series? Would it go like this? Ape, brute, oaf, not just an oaf, not quite an oaf, somewhat less oafish than when last noticed, many oafish characteristics seem to have been lost ... not half the oaf he used to be ... ? How would it really work?
It's much easier to picture such a process for physical appearance, as in the famous Ascent of Man graphics in pop science magazines, than for the origin of human consciousness. But is even that fabled Ascent of Man just a modern myth? Science writer Henry Gee explains in Nature, "We have all seen the canonical parade of apes, each one becoming more human. We know that, as a depiction of evolution, this line-up is tosh. Yet we cling to it."
If we continue on our present course, we not only cling to it, we are stuck with it. If we wanted to chart a new course, we must begin by asking, what can we responsibly believe, based on what we know, about human evolution?
Editor's note: Here are links to the whole "Science Fictions: Human Evolution" series to date.