If you were going to argue that any species on Earth is the product of intelligent design, then humans would be a pretty logical choice – after all, we’re the only species that’s capable of knowing whether we’re designed, and if so, of inquiring as to who our Designer might be. That makes us a pretty remarkable species. In a recent unsigned post, Evolution News and Views attempts to summarize the evidence for humans as products of intelligent design. Unfortunately, it does such a poor job that it ends up shooting itself in the foot. In this post, I’d like to highlight the questions which any halfway-decent case for humans being design products needs to address, and suggest a few answers.
Briefly, the questions which any theory positing that humans were designed needs to answer are as follows:
(1) What exactly are human beings?
(2) Which physical and mental attributes of human beings can we confidently say were designed?
(3) Did these attributes all appear at once? And if not, what are the implications for human equality?
(4) Which hominins in the fossil record qualify as human?
(5) Can we identify the point in the fossil record at which human beings appear, as products of intelligent design? If not, why not?
What exactly are human beings?
The recent ENV post provides us with no definition of “human being,” so it fails to address question (1). We are told that “[o]ur capacity for abstract thought, self-conscious reflection, and ability to communicate put us in another category entirely” from the apes. Later, we are informed: “Humans are the only species that uses fire and technology.” Then we read that “[h]umans are the only species that composes music, writes poetry, and practices religion.” A little further on, we learn more: “Humans are also the only species that seeks to investigate the natural world through science.” Then there is a quote from Noam Chomsky: “Human language appears to be a unique phenomenon, without significant analogue in the animal world…” Finally, we come across this claim: “Some of our moral abilities cannot be explained by natural selection.” OK, so which of these is the “human-making” property? Is it fire use, technology, science, language, abstract thought, self-conscious reflection, morality or religion? And if it’s all of the above, then why do all of these capacities go together? Why are they inseparable?
If I had to pick just one or two of these abilities, I would focus on language and theory of mind. Arguably, these two abilities undergird the other distinctively human cognitive abilities. There can be no distinctively human thought without language, and there can be no art, morality or religion without a belief in other minds, each having their own perspective on the world. Intelligent Design theorists would do well to focus exclusively on these two abilities, and search for scientific evidence of their having been designed.
Which physical and mental attributes of human beings can we confidently say were designed?
Question (2) is answered near the end of the ENV post: “Humanity’s unique physical, behavioral, and cognitive abilities collectively show the design of our species.” Unfortunately, the article says little about the physical features which distinguish us from the apes, beyond noting that “we have many more finely controlled muscles in our hands, face, and tongues” that apes lack, without which we would be incapable of artistic dexterity, language or the ability to express a range of subtle emotions in our faces. Later, we are told that humans “are the only primates that always walk upright, have relatively hairless bodies, and wear clothing,” but we are not told whether our upright stance, bodily nakedness and use of clothing are part of the way we were designed. Apparently, the author of the post believes that all of the human cognitive abilities listed in the preceding paragraph were designed by our Maker, too – meaning, presumably, that not one of them is a mere by-product of some other, more fundamental cognitive feature. That in turn means that all of our distinctive cognitive abilities are equally fundamental, which is quite a tall claim to make. Such a claim needs justification.
The author of the latest ENV post also appears badly confused about the number of beneficial mutations that were required to make us human:
How many mutations would it take to evolve the anatomical changes necessary for walking and running? Dozens if not hundreds or thousands — if it could happen by random mutation at all. If the time span available for human evolution from a chimp-like ancestor is six million years, the effective population size is ten thousand, the mutation rate is 10^-8 per nucleotide per generation and the generation time is five to ten years (for a chimp-like ancestor), only a single change to a particular DNA binding site could be expected to arise. It strains credibility to think that all sixteen anatomical features evolved fortuitously in that same time frame, especially if each required multiple mutations. Given these numbers, it is extremely improbable, if not absolutely impossible, for us to have evolved from hominin ancestors by a gradual, unguided process.
Two comments are in order here. First, the number of beneficial mutations that have been fixed in the line leading to human beings was calculated ten years ago by Dr. Ian Musgrave, over at Panda’s Thumb: it’s about 240. Musgrave adds:
As for neutral mutations, Professor Larry Moran has supplied the answer, in his post, Why are the human and chimpanzee/bonobo genomes so similar? (February 28, 2014):
The human and chimp genomes are 98.6% identical or 1.4% different. That difference amounts to 44.8 million base pairs distributed throughout the entire genome. If this difference is due to evolution then it means that 22.4 million mutations have become fixed in each lineage (humans and chimp) since they diverged about five million years ago.
The average generation time of chimps and humans is 27.5 years. Thus, there have been 185,200 generations since they last shared a common ancestor if the time of divergence is accurate. (It’s based on the fossil record.) This corresponds to a substitution rate (fixation) of 121 mutations per generation and that’s very close to the mutation rate as predicted by evolutionary theory.
It is distressing to see Intelligent Design proponents arguing for the design of the human body, without even bothering to familiarize themselves with these numbers. That’s what I call leading with your chin.
The logical course of action for an ID advocate would be to focus specifically on the beneficial mutations that have enhanced the human brain, identify precisely what each of them does, and search for signs of design in these mutations. There shouldn’t be too many: perhaps a couple of dozen. That’s a manageable research task: not too big and not too small.
Did these attributes all appear at once? And if not, what are the implications for human equality?
Question (3) is not addressed at any point in the ENV post. But the question is an important one, which needs to be confronted. To be sure, there is a difference between a behavioral or cognitive capacity and the manifestation of that capacity. For instance, science, as an enterprise, goes back no further than 2,500 years, and yet hunter-gatherers (whose lifestyle has remained largely unchanged for millennia) have no problem in grasping core scientific concepts: indeed, any normal human can master them. But suppose we were to find a tribe of people who proved to be utterly incapable of grasping mathematics, science, philosophy or religion, no matter how many times these subjects were explained to them. Suppose too that this tribe’s DNA revealed that it branched off from the ancestors of other modern humans at a very early date. We might reasonably conclude that some of the cognitive abilities we consider distinctively human arose after the date when the tribe’s ancestors diverged from those of other modern humans. In that case, should we view the members of the tribe as our equals, or our inferiors? If the former, why? Again, what if it turned out the Neandertals lacked some of these abilities? Does that make them inferior to Homo sapiens? If not, why not? The question is an especially pressing one for “human exceptionalists,” most of whom are fervent egalitarians who oppose any form of scientific racism. But if was Stephen Jay Gould, a scientist who campaigned tirelessly against racism and sexism, who declared: “Human equality is a contingent fact of history” (The Flamingo’s Smile, Harmony Books hardcover edition, 1985, p. 186). In his eponymous essay, Gould invites his readers to imagine what would have happened if Australopithecus robustus, which died out around one million years ago, had survived down to the present day: “It might well have survived and presented us today with all the ethical dilemmas of a human species truly and markedly inferior in intelligence (with its cranial capacity only one-third our own). Would we have built zoos, established reserves, promoted slavery, committed genocide, or perhaps even practiced kindness?”
Which hominins in the fossil record qualify as human?
Question (4) is addressed only obliquely in the ENV post. There is a quote from Science and Human Origins (Discovery Institute Press, paperback, 2012, p. 45): “Hominin fossils generally fall into one of two groups: ape-like species and human-like species, with a large, unbridged gap between them.” This, I have to say, is nonsense. Three hominins are more than enough to refute the charge: Homo naledi, Homo erectus georgicus and Homo floresiensis. On which side of the divide do each of these hominins fall, and why?
Homo floresiensis appears to have shared some anatomical similarities with Australopithecus sediba, Homo habilis and especially, Homo erectus georgicus, as well as having a brain that was no larger than a chimp’s (380 cubic centimeters), although curiously, its dorsomedial prefrontal cortex, an area of the brain associated with higher cognition, is about the same size as that of modern humans, and the species appears to have made simple stone tools, similar to those used in the region one million years ago, and possibly used fire for cooking (however, this is controversial). Some scientists have even proposed that the species was capable of building bamboo rafts (which would have required the use of language), thereby enabling them to cross the 19-kilometer straits separating their island from the Indonesian mainland. Other experts, who are more skeptical, have suggested that they may have drifted across on natural rafts, instead.
As for Homo naledi, Wikipedia describes it as an “an anatomical mosaic,” remarking: “The physical characteristics of H. naledi are described as having traits similar to the genus Australopithecus, mixed with traits more characteristic of the genus Homo, and traits not known in other hominin species.” The brain size of this hominin varied from 450 to 610 cubic centimeters, which is less than half that of Homo sapiens. Nevertheless, some creationists, such as Todd Wood, consider it human, on the grounds that there is good evidence that it buried its dead (see here for a brief discussion of alternative hypotheses).
Homo erectus georgicus dating from 1.8 to 1.7 million years ago had an average brain size of just 686 cubic centimeters, which is well outside the modern human range. The only tools made by this subspecies are those belonging to the primitive (Mode I) Oldowan culture of early Homo. Wikipedia adds:
The fossil skeletons present a species primitive in its skull and upper body but with relatively advanced spine and lower limbs, implying greater mobility than the previous morphology. It is now thought not to be a separate species, but to represent a stage soon after the transition between H. habilis to H. erectus; it has been dated at 1.8 mya…
Two of the skulls — D2700, with a brain volume of 600 cubic centimetres (37 cu in), and D4500 or Dmanisi Skull 5, with a brain volume of about 546 centimetres — present the two smallest and most primitive Hominina skulls from the Pleistocene period.
If Homo erectus is to be regarded as human, then we will have to accept this subspecies of Homo erectus as human, too, despite its primitive skull and upper body.
Dr. Ann Gauger has informed me that she regards Homo erectus (who appeared 2 million years ago) as the first true human being, but on largely theological grounds: “The reason I place Adam so far back? It is the problem of ensoulment, of monogenism, and of genetics… It solves the problem of an huge initial population size, and gives pop[ulation] gen[etics] time to work… I have difficulty accepting that God would have parallel races derived from the same ancestry, and ensoul some and not others. That’s if I accept common ancestry. With a unique origin that is early, everyone is ensouled.” I sympathize strongly with Dr. Gauger’s concerns here, but this is not by any stretch of the imagination a scientific argument.
To be fair, however, Dr. Gauger does put forward some scientific arguments for the full humanity of Homo erectus. Her first argument relates to Homo erectus‘ ability to create aesthetically pleasing objects, such as the master handaxe found at Kathu Pan in South Africa, and dating back to 800,000 years ago. She cites a 2015 paper by Stout et al., arguing that Acheulean toolmaking was more difficult than it appears, imposing a host of complex cognitive control demands on the individuals who made them, including planning/simulation of future actions and mental time-travel. On the other hand, the authors of a 2016 paper by Corbey et al., titled, The acheulean handaxe: More like a bird’s song than a beatles’ tune?, argue that the form of Acheulean handaxes was at least partly under genetic rather than cultural control. Additionally, the authors contend that Acheulean handaxes “do not exhibit the kind of signal predicted by cultural evolutionary models and ethnographic data,” and that social learning of axe-making techniques would have resulted in greater copying errors than that observed in the archaeological record. Furthermore, the very slow rate of change in the design of the Acheulean handaxe is inconsistent with what we know about cultural transmission. In particular, “the greatly increased rate of technological change observed in post‐Acheulean industries” is “difficult to square” with the notion that Acheulean handaxe design was transmitted culturally. The authors propose that the design of Acheulean handaxes was shaped by genetic constraints, pointing to bird nests as examples of how complex structures may arise through a combination of innate behaviors and individual learning, without the need for cultural transmission.
Another argument mentioned by Dr. Gauger relates to Homo erectus‘ ability to use fire. There is evidence that Homo erectus was able to tame fire as far back as 1,000,000 years ago, and perhaps use it to cook meat as well. The recently reported evidence for the controlled use of fire at Wonderwerk cave in South Africa has impressed some anthropologists. Others, however, are more skeptical. Wil Roebroeks of Leiden University in the Netherlands and Paola Villa, a curator at the University of Colorado Museum of Natural History in the U.S, commented as follows: “Is the Wonderwerk evidence good enough to suggest that hominins a million years ago were regular fire users all through their range? A definite ‘no’ – we do not have the evidence to back up such a claim, before 400,000 years ago.” The more recent date of 400,000 years ago means that the controlled use of fire was an innovation that may well have been due to Heidelberg man.
A further piece of evidence for cognitive sophistication on the part of Homo ergaster / erectus, touched on by Dr. Gauger, relates to this hominid’s ability to transport pieces of rock over a distance of 12-13 kilometers, compared with just tens or hundreds of meters for Australopithecus and early Homo (see here). This does indeed suggest a certain degree of foresight on the part of Homo ergaster / erectus, but it can hardly be considered definitive proof.
I should add that until a few years ago, many anthropologists believed that there were stark anatomical differences between the ape-like Australopithecus and the more human-like Homo erectus, and many of them also believed that Homo habilis should be classified as a species of Australopithecus. This view is now regarded as out-of-date. Recent papers published in 2012 – see Early Homo: Who, When, and Where (by Susan C. Antón, in Current Anthropology, Vol. 53, No. S6, “Human Biology and the Origins of Homo,” December 2012, pp. S278-S298), Origins and Evolution of Genus Homo: New Perspectives (by Susan C. Antón and J. Josh Snodgrass, in Current Anthropology, Vol. 53, No. S6, “Human Biology and the Origins of Homo,” December 2012, pp. S479-S496) and Human Biology and the Origins of Homo: An Introduction to Supplement 6 (by Leslie C. Aiello and Susan C. Antón, in Current Anthropology, Vol. 53, No. S6, “Human Biology and the Origins of Homo,” December 2012, pp. S269-S277) show that the transition from Homo habilis to early Homo ergaster / erectus was not much larger than that between Australopithecus and Homo habilis. A detailed anatomical comparison (see the article by Antón and Snodgrass, cited above) indicates that the transition from Australopithecus to early Homo, who appeared about 2.3 or 2.4 million years ago, and from early Homo to Homo ergaster / erectus, is much smoother and more gradual than what anthropologists believed it to be, ten years ago. The authors write:
The shift from Australopithecus to Homo was marked by body and brain size increases, a dietary shift,
and an increase in total daily energy expenditure. These shifts became more pronounced in H. erectus, but the transformation was not as radical as previously envisioned.
Back in 2013, over at Uncommon Descent, I wrote a lengthy post arguing the case for Heidelberg man as Adam, which would have made all his descendants (Denisovan man, Neandertal man and Homo sapiens) human as well. I don’t know any other Intelligent Design proponent or creationist who has championed this opinion. However, there are two problems with this view: first, many scientists now doubt the validity of Homo heidelbergensis as a taxon – news that was apparently greeted with glee by certain creationists. Additionally, there seems to be no clear-cut transition between Heidelberg man, his supposed ancestor, Homo erectus, and his purported descendants (Denisovan man, Neandertal man and Homo sapiens), which makes it very difficult to draw up a list of unique characteristics that distinguish Heidelberg man from his evolutionary predecessors and successors.
Finally, there are some creationists (notably, Hugh Ross and Fazale Rana) who believe that only Homo sapiens qualifies as truly human, meaning that the Neandertals were brute beasts, lacking rational souls – a view that is difficult to square with evidence presented by Dediu and Levinson, in their paper, On the antiquity of language: the reinterpretation of Neandertal linguistic capacities and its consequences (Frontiers in Psychology, 4:397. doi: 10.3389/fpsyg.2013.00397), indicating that they possessed language.
The Neandertals managed to live in hostile sub-Arctic conditions (Stewart, 2005). They controlled fire, and in addition to game, cooked and ate starchy foods of various kinds (Henry et al., 2010; Roebroeks and Villa, 2011). They almost certainly had sewn skin clothing and some kind of footgear (Sørensen, 2009). They hunted a range of large animals, probably by collective driving, and could bring down substantial game like buffalo and mammoth (Conard and Niven, 2001; Villa and Lenoir, 2009).
Neandertals buried their dead (Pettitt, 2002), with some but contested evidence for grave offerings and indications of cannibalism (Lalueza-Fox et al., 2010). Lumps of pigment — presumably used in body decoration, and recently found applied to perforated shells (Zilhao et al., 2010) — are also found in Neandertal sites. They also looked after the infirm and the sick, as shown by healed or permanent injuries (e.g., Spikins et al., 2010), and apparently used medicinal herbs (Hardy et al., 2012). They may have made huts, bone tools, and beads, but the evidence is more scattered (Klein, 2009), and seemed to live in small family groups and practice patrilocality (Lalueza-Fox et al., 2010).
I should point out, however, that Dediu and Levinson’s 2013 paper has been critiqued by Berwick, Hauser and Tattersall, who argue in their commentary that: (i) “hominids can be smart without implying modern cognition”; (ii) “smart does not necessarily mean that Neanderthals had the competence for language or the capacity to externalize it in speech”; (iii) the earliest unambiguous evidence for symbolic communication dates from less than 100,000 years ago; and (iv) although they may have had the same FOXP2 genes as we do, “[n]either Neanderthals nor Denisovans possessed human variants of other putatively ‘language-related’ alleles such as CNTAP2, ASPM, and MCPH1.”
Recent evidence seems to bear out the authors’ skepticism about the Neandertals’ use of language. Scientists at the 2017 annual meeting of The American Society of Human Genetics discussed the significance of Neandertal genes, pointing out that “some ‘Neandertal’ genetic variants inherited by modern humans outside of Africa are not peculiarly Neandertal genes, but represent the ancestral human condition,” according to a report by Ann Gibbons in Science magazine (October 23, 2017). But there was more. New findings strongly suggest that the Neandertals would have suffered some severe speech impediments, if they spoke at all:
Other geneticists at the meeting zeroed in on archaic DNA “deserts,” where living humans have inherited no DNA from Neandertals or other archaic humans. One of these regions includes the site of the FOXP2 “language” gene. This suggests that in our ancestors, natural selection flushed out the Neandertal version of this gene. Using statistical software that evaluates gene expression based on the type of gene, Vanderbilt graduate student Laura Colbran found that Neandertal versions of the gene would have pumped out much less FOXP2 protein than expressed in modern brains. In living people, a rare mutation that causes members of a family to produce half the usual amount of FOXP2 protein also triggers severe speech defects, notes Simon Fisher, director of the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands, who discovered the gene. Expression of FOXP2 may be key to language, Fisher says.
The upshot of all this is that unless ID proponents want to give up their belief in human equality, they would do best to bite the bullet and accept the fact that there’s something pretty unique about Homo sapiens, after all. If any human species was designed, it’s this one. I might add that if the “human-making” attributes are language and a theory of mind, these appear to have originated with our species. Art, science and religion seem to be unique to our species as well, although there is evidence that the Neandertals buried their dead.
One could perhaps argue (following Dubreuil) that morality goes back to Heidelberg man, with his capacity for self-sacrifice. But Dubreuil’s case, while impressively argued, remains speculative. And human morality without a theory of mind really does sound rather odd.
Can we identify the point in the fossil record at which human beings appear, as products of intelligent design?
Once again, the ENV post makes no attempt to address this question. However, there are already hints of an answer.
As we have seen, there are no clear-cut boundaries between Australopithecus and early Homo, between early Homo and Homo erectus, between Homo erectus and Heidelberg man, and between Heidelberg man and Neandertal man. However, there is one species whose appearance in the fossil record is relatively sudden: Homo sapiens. As Ian Tatterall and Jeffrey Schwartz put it in their article, The morphological distinctiveness of Homo sapiens and its recognition in the fossil record: Clarifying the problem (Evolutionary Anthropology, Volume 17, Issue 1, pp. 49-54):
Species are historically differentiated entities that, osteologically, may be differentiated to inconveniently varying extents. Living Homo sapiens is a distinctive morphological entity that is easily distinguished in both cranial and postcranial morphology from all other living hominoids and from the vast majority of its fossil relatives.
In his 2012 book, Masters of the Planet, paleoanthropologist Ian Tattersall American Museum of Natural History argues that Homo sapiens had a highly distinctive appearance which marks him out from other hominids: “[e]ven allowing for the poor record we have of our close extinct kin, Homo sapiens appears as distinctive and unprecedented.”
I’d like to draw readers’ attention to Benoit Dubreuil’s well-argued essay, Paleolithic Public Goods Games: Why Human Culture and Cooperation Did Not Evolve in One Step (Biology and Philosophy (2010) 25:53–73, DOI 10.1007/s10539-009-9177-7). Dubreuil’s claim is that the human prefrontal cortex reached its present form about 700,000 years ago, with the appearance of Heidelberg man, whose advanced prefrontal cortex conferred on him “modern-like abilities for inhibitory control and goal maintenance.” In plain English, Heidelberg man’s advanced cortex meant that he was able to control his selfish impulse to turn tail and run from dangerous predators, and put his own life at risk in order to defend the “greater good” of the group; additionally, he was able to make long-term plans and commitments relating to his and his family’s future. These advances, Dubreuil believes, would have allowed Heidelberg man to hunt big-game (which is highly rewarding in terms of food, if successful, but is also very dangerous for the hunters, who might easily get gored by the animals they are trying to kill) and make life-long monogamous commitments (for the rearing of children whose prolonged infancy and whose large, energy-demanding brains would have made it impossible for their mothers to feed them alone, without a committed husband who would provide for the family) became features of human life. Dubreuil refers to these two activities as “cooperative feeding” and “cooperative breeding,” and describes them as “Paleolithic public good games” (PPGGs). He believes that Homo erectus lacked these abilities: while there’s good evidence that he ate a lot of meat, there’s no good evidence that he hunted large-scale game. Dubreuil thinks he was probably an active scavenger, which means that he ate meat from carcasses that other animals had killed, and confronted any creature that tried to stop him eating.
Given the strong claims made by Dubreuil on behalf of Heidelberg man, it is all the more surprising to find him readily acknowledging that the human brain did not stop evolving there: the distinctive features of Homo sapiens‘ brain enabled modern man to make further cognitive advances, relating to theory of mind, language, symbolism and art. These advances, Dubreuil believes, were triggered by developments in the temporoparietal cortex of the brain, rather than the prefrontal cortex:
One of the most distinctive features of Homo sapiens’ cranium morphology is its overall more globular structure. This globularization of Homo sapiens’ cranium occurred between 300 and 100,000 years ago and has been associated with the relative enlargement of the temporal and/or parietal lobes (Lieberman et al. 2002; Bruner et al. 2003; Bruner 2004, 2007; Lieberman 2008). Paleoneurological reconstructions are currently insufficient to identify the precise regions that benefited from globularization. It is not unreasonable, however, to link this change with a functional reorganization of the higher association areas of the temporal and parietal areas…
The temporoparietal cortex is certainly involved in many complex cognitive tasks. It plays a central role in attention shifting, perspective taking, episodic memory, and theory of mind (as mentioned in Section “The role of perspective taking”), as well as in complex categorization and semantic processing (that is where Wernicke’s area is located)…
I have argued elsewhere (Dubreuil 2008; Henshilwood and Dubreuil 2009) that a change in the attentional abilities underlying perspective taking and high-level theory of mind best explains the behavioral changes associated with modern Homo sapiens, including the evolution of symbolic and artistic components in material culture.
Finally, I’d like to close with a quote from a paper by M. Somel, X. Liu, and P. Khaitovich, titled, Human brain evolution: transcripts, metabolites and their regulators, in (2013) Nature Reviews Neuroscience 14, 112–127, (February 2013), doi: 10.1038/nrn3372. The authors write:
There is accumulating evidence that human brain development was fundamentally reshaped through several genetic events within the short time space between the human-Neandertal split and the emergence of modern humans. (Somel et al., 2013, p.119, emphases mine.)
In short: if we were going to pick a hominin species which was clearly marked off from its predecessors (and from other contemporaneous species), it would have to be Homo sapiens.
Is there a clear point in time when the act of design that made us human might have occurred? recent discoveries have pushed the origin of Homo sapiens back to at least 300,000 years ago, and we still don’t know if this was a sudden or a gradual event. On the other hand, the great leap forward in human culture seems not to have taken place until about 100,000 years ago, which is when modern human behavior emerged in South Africa. This seems to have been a relatively sudden event.
So if there was a special intervention in human history, that’s when I’d look for it. But a 100,000-year-old dawn of humanity doesn’t sit well with monogenism, as Dr. Ann Gauger is well aware. Be that as it may, the best thing for the ID movement to do right now would be to take the advice of the late Sir Anthony Flew, and “follow the evidence wherever it leads.” Amen to that.