Human origins: take care with the evidence

This article by STEVE DRURY continues a discussion of the origins of human culture and morality. People & Nature last month published a review by Steve of Christopher Boehm’s book Moral Origins: The Evolution of Virtue, Altruism and Shame. Chris Knight of the Radical Anthropology Group took issue with the review in an article, The Revolution That Worked. Here, Steve Drury responds to Chris Knight.

hand print

Hand print made with red ochre at the Chauvet cave, southern France, about 30,000 years ago

In his comments on my review of Christopher Boehm’s Moral Origins, Chris is concerned that I view the drift of Boehm’s argument as characteristic of sociobiology. Since I was asked to review that book and not Boehm’s life’s work, I stand by that as a sociobiological, “neo-Darwinian” perspective is what the entire book implies. Anyone can say – in another book, in this case – that they are against a scientific or philosophical tendency, but that is not something that leaps from the page when they explicitly use its methodology, as Boehm does in Moral Origins with his continual rumination about how this or that form of Darwinian selection shaped human morality.

Let’s remind ourselves: natural selection of whatever kind takes place at the level of the individual. Its outcome, the harnessing of an attribute controlled by a particular form of a gene (allele) that is favourable for future fitness is passed to descendants of that individual who express its particular function and may pass it on further. As Steven Rose and many other biologists have discovered and emphasised, biological heritage is a great deal more complicated than that.

I know of no evidence that cultural attributes developed collectively by socially conscious beings are passed on in that way. Yet the ability for conscious behaviour of individuals in such a society does seem inevitably to be connected to the genome that they inherited but is certainly not determined absolutely by it, as the sociobiologists etc would have us believe.

My view of Boehm’s book and his other work on this topic is coloured by some general principles in the natural sciences, including (1) to make sure you keep up with developments in that field and (2) not to omit deliberately evidence unfavourable to one’s ideas. I found that Boehm avoids both responsibilities.

In the first case he takes the molecular-clock age for a split between an evolutionary branch towards humans and another towards living chimps and bonobos as being fixed for all time. In fact it is a very crude estimate based on far more questionable assumptions than is dating using radioactive decay, which also has its limitations. The rates of human and chimp mutation, on which ‘molecular clocks’ depend, are only crudely understood. The timing of evolutionary branchings split on degree of dissimilarity between human and chimp genomes, those of both with gorillas and orang-utans have recently been put back by a long time, which opens up a host of new possibilities. No doubt assigning age to points of genetic divergence will undergo further development.

In the second case, in his trying to justify a parsimonious reconstruction of behavioural aspects of “Ancestral Pan” Boehm simply omits a wealth of widely known, convincing evidence for broad behavioural norms among 6 million years worth of hominin fossils. His most telling omission in my view is the lack since about 6 million years ago of prominent canines (the central feature of male competition for females among other living, dominantly vegetarian great apes). Another is the marked decrease in the difference between male and female stature with the emergence of the first well-described human species (Homo ergaster), which may signify something about a change in male dominance over females, and has been suggested to mark the origin of pair bonding: there may be other possibilities. That occurred at some time before about 2 million years ago, as did the first occurrence of stone tools in the archaeological record.

Boehm also takes the idea of a “last common ancestor”, derived by comparison of different species’ genomes, as indicating that such a being had to be behaviourally similar to one or the other living species, his choice being the chimpanzee. That is convenient for his thesis, but may not be valid. Among many equally likely possibilities, he could have considered it to be, for instance, an upright ape without massive canine teeth, but doesn’t even cite the possibilities. My mention of the 7-9 million-year old fossil ape from Italy, Oreopithecus, which had small canines and an upright gait, is a case in point. A more recent publication implies that descendants of that being might have migrated together with other animals from Europe to Africa at a time when the Strait of Gibraltar was closed between 5.3 to 5.6 million years ago, which strengthens the point. Boehm might also have considered a pertinent view that chimps and gorillas have evolved to specialised ecological niches from very different common ancestors, whereas hominins seem to have been widely distributed generalists. He could also have made it clear that fossil evidence for animals on the chimp or gorilla branches of the great-ape evolutionary ‘bush’ has yet to be found.

Boehm’s point of departure is, in my view, undermined by these points and I took up his omission of them in my review. Chris makes no comment on that important issue. I felt that Boehm had chosen to break some basic scientific principles in order to shore-up his long-held thesis about human origins. And that kind of trait simply goes on and on in what is a somewhat woolly book.

My views are not coloured by how highly Boehm is regarded in anthropological circles. In an era when the whole of science is warped by the influence of capital it is easy to be lionised when one climbs on a bandwagon with other ambitious liberals such as Steven Pinker and Jared Diamond – hence my attention to Boehm’s political conclusions that coincide with theirs and with Thomas Hobbes’s Leviathan, i.e. an embrace of the bourgeois state. As to whether Boehm is a theoretical “friend”, I’m not sure I would like as a pal, or as a neighbour, someone who reckons humanity’s current difficulties could be resolved by a “nuclear war with the destructive power of the whole of world war two, or a similar global disaster”, that “might galvanise our entire world of nations”!

It is pretty clear from my review that I find the obsession with cranial capacity as a sign of “human potential” somewhat Victorian. Revolutions there almost certainly were, throughout the development of the genus we call Homo, but concrete evidence in palaeontology and archaeology is notoriously hard to come by, and hard to interpret convincingly.

The central role of iron-based pigments in early human culture is a case in point: to recognise either rock  art or pigments for body painting is potentially key to a great deal. Really convincing stuff first appears more than 100,000 years ago in the African record and is associated with anatomically modern human remains. But there is so much ochre in African geology – much of the continent is at least as red as Australia (!) – that it is exceeding difficult to tell whether more widely scattered pieces of ochre are natural debris or artefacts. Probable ochre artefacts that have been found are from caves or rock shelters that offer the best chance of finding preserved human remains and other tools. Camp sites in open ground are far less likely to be preserved in the record; the more so further back in time because of erosion. Yet we can see, from citations by members of the Radical Anthropology Group in which Chris participates (e.g. here), the record of probable hominin-associated ochre-pigment goes back to around 600,000 years, i.e. well before the time of “fully modern” humans. I’d place a substantial bet that anthropogenic ochre objects will eventually be discovered in Africa much further back in time, much in the manner that the age for the earliest evidence for deliberate use of fire and cooking foodstuffs is steadily increasing.

It was a bit of a tired ruse by Chris to try to undermine what I had to say by suggesting a link with old Colin Renfrew. I think a closer read of my review would reveal that my emphasis on the shift to settlement and the domestication of nature, during the “agricultural revolution” – not my phrase! – is not quite the same as that of many Meso- to Neolithic archaeologists. In terms of human production of the means of life it certainly was a revolution, but carried within it the seeds of its opposite. In less than 10,000 years, that opposite – serfdom, slavery and alienation of human from human, humans from the natural world, and the majority from the richness of human culture – materialised and reached its global limits in the form of capital. I’d shift the designation of a life that is “solitary, poor, nasty, brutish, and short”  (another Hobbesianism!) to the majority of people, who in these societies became the objects of agriculture-dominated economics and the forms of state it supported. To escape from it the most profound social revolution is required: the negation of the sudden shift from nomadic hunter-gatherer to settled agricultural and pastoral economy following the end of the last glacial period. Then people stand a chance of being “fully human”.

As regards my “anti-revolutionary” stance, I think Chris will find that I focus on the development of tools, their passing-on across time and space, and the emergence of consciousness as a unique and fundamental break between humans and the rest of nature. That revolution lies at the root of social being: the condition for subsequent social revolution. It partially and progressively freed humans from genetic “tyranny” that stemmed from being a passive part of the struggle with the rest of nature. As our human ancestors found themselves able to transform nature they discovered they could also change themselves through culture. Indeed, as beings with the weakest physique on the African plains and easy and probably quite tasty prey for big predators, they had to.

The interplay of culture with natural forces, within and outside human physiology, also transformed how genetic evolution shaped the human frame from its basic 2 million old model: a broader topic and potentially an object lesson in the dialectics of nature that Engels and Marx were not equipped to consider.  One aspect to be considered is a host of physiological features that, in a purely Darwinian sense, would have made humans less “fit”. The classic examples are: a general increase in physical “fragility”; birth at an earlier stage of foetal development to avoid increased pelvic stress from an enlarged cranium; and the related delay in infant development and dependency.

Through cultural development in a social context we have reached the stage where there is no “human nature”, behaviourally speaking, from which we cannot break … even though the last 10,000 years has shown how human control over behaviour is a double-edged and potentially catastrophic sword.

Egalitarianism, empathy and selfless altruism expressed in hunter-gatherer cultures, how they arise and their continuation in all modern societies, despite alienation, are central to a perspective of revolutionary social change. The weakening of the “tyranny” of natural selection and of an inescapable “human nature” equip us for changing ourselves through changing the world. The sociobiology cum neo-Darwinism that I believe permeates Moral Origins, whether actively or through negligence, is one of the biggest hindrances to that perspective.

Steve Drury’s review of Moral Origins is here

Chris Knight’s article The Revolution That Worked is here

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One Response to Human origins: take care with the evidence

  1. […] Christopher Boehm’s book Moral Origins, and the exchange that followed between Chris Knight and Steve Drury. […]

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