On page 100 of Not by genes alone (Boyd, 2005) Richerson and Boyd say “one of Charles Darwin’s rare blunders was his conviction that the ability to imitate was a common animal adaptation”. It is today less clear where the blunder lies. Many species of animal seem to learn by observation. It is possible that Richerson’s and Boyd’s assertion is based on the fact that that for many species there is not a lot to learn. Eating grass, where there is grass, is not a complex operation, and lambs and calves do not have to be disciplined into watching adults at work for hours before they take their first nibble. With lions and wolves the case is different.
If this is an error, it is a small one. But on page 83 Boyd and Richerson make a far more sweeping and dogmatic assertion under the heading Cultural variants are not replicators. Here they present Richard Dawkins’ throwaway, he says so himself, suggestion of memes as being replicators, and then quire rightly dismisses it. But while memes might be the playground of people incapable of the kind of reductionism that science requires, Boyd and Richerson, instead of testing their assertion, accept it as a fundamental truth and build the rest of their thesis on it. Which I think is a pity, because Not by genes alone is a great trailblazing book, and contains a huge amount of valuable explanation and reasoning. While I don’t agree with all of it, it’s a must-read for anybody interested in cultural evolution.
On the other hand I think the unexamined assumption that cultural variants are not replicators has been damaging to the pursuit of what is the case, and allowed a whole slew of what, put politely, you could call holistic thought, often wrapped in abstruse mathematics where the basic functions are chimeras, to undermine what would like to be accepted as science.
And so I propose, in a bid to prevent the whole concept of cultural evolution falling into extinction when the funding has wrung it dry, a thought experiment. Let us suppose that there is a cultural variant at a certain scale, that it does replicate with fidelity, and that it is as numerous as genes. And let us suppose that cultural evolution is indeed the process of the emergence of human culture, and this process is strictly Darwinian.
The question of what the Darwinian “factor”, certainly not memes or genes, actually is is easily answered, without resort to metaphysics, mumbo jumbo or the summoning of strange and inexplicable forces beyond our ken. It’s not the principle that’s difficult, but the number of deeply engrained pre-Enlightenment thought processes that have to be disrupted in order for the principle to be accepted. If cultural evolution is Darwinian, then like all evolution the rate of change is at the lithic plate level, very slow, centimetres per year. Or maybe it depends on the extinction of weak variants. As Niels Bohr said, “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather its opponents eventually die, and a new generation grows up that is familiar with it.”
I have already developed this thought experiment in a horribly discursive hundred and forty thousand words which my wife is fairly brutally helping me to fine down to a more acceptable hundred thousand, and I will weary you with that no more just now.
For the moment, just a few indicators. I start with a tweet, the irreducible (well, reduced to 140 characters) nucleus of Darwinian theory:
observed phylogenetic heritability, incessant replication with fidelity, an envelope of fractional variation, selection by external factors.
The indigestible bare bones of the hypothesis are here:
that human culture, which is to say the extended human phenotype, is a subset of the mass of the universe that has evolved, in the manner described by Darwin, step by step and alongside and in obligate symbiosis with the hominin organism.
That, it suggests, is how human culture emerged, in obligate symbiosis with the hominin line from about 3.2 million years ago, step by minute step.
This would be consistent with the findings of the Discussion meeting issue ‘Major transitions in human evolution’ organized and edited by Robert A. Foley, Lawrence Martin, Marta Mirazón Lahr and Chris Stringer.
The conclusion of this conference is that the evolution of the human organism and the available coincident archaeology point to a gradual, very gradual development of material cultural forms down and across a vertical and horizontal matrix of hominin species.
And what is such a supposition worth? Well, clearly it needs detailed explication. Most intractably opposed to it is the belief that the Darwinian model is dependent on “life” and genes. Clearly it is not dependent on genes, of which Darwin knew nothing. It is dependent on, his word, “factors”. As for life, that life should be crucial to natural selection seems to me an arbitrary assumption. The material universe is continuous, in all dimensions, and I argue, I hope at least testably, that the Darwinian model applies to anything that conforms to it, and not to anything that doesn’t. Thermodynamics, chemistry and physics are just as germane as life to a Darwinian theory of evolution. I have read Nick Lane as well as “On the Origin of Species”.
At the moment the extended human phenotype (in the sense in which Richard Dawkins uses it) weighs in at around thirty trillion tons (Scale and diversity of the physical technosphere: A geological perspective: Jan Zalasiewicz et al). This has increased by orders of magnitude from a few kilogrammes of flakes struck by the first Australopithecine technologists maybe 3.2 million years ago. By at the latest around 195kya the Homo sapiens brain had reached its present size and shape, and therefore its present energy consumption. Meanwhile, the evolution of the lithic technology was preceding at its usual smooth and unhurried rate. How in the final analysis in energy input and output terms can the existence of this big brain be accounted for? Chris Stringer has suggested “social complexity”, but social complexity at its widest might mean the totality of the relationship of human beings with each other and their collective extended phenotype, in which case it elides the explanation with the thing it tries to explain; or social complexity could just mean various gradations of immediate, physically mediated social relationships, which a) are in themselves an energy cost, not a source and b) may not do much to distinguish us, let alone Homo sapiens circa 200,000 years ago, from wolves, killer whales or elephants.
Of course energy sources, that is to say fuel for respiration, can emerge in the context of social complexity, at whatever scale you choose to apply it, but this emergence will have been in evolutionary time, not rapid enough to prevent the immediate extinction that the energy consumption of the increasing brain size might incur if in competition with, say, socially coherent groups of probably Homo erectus that were producing Fauresmith stone blades half a million years ago. The evolution of all life forms suggests that if a species can successfully do what it does with less energy, the less energy consuming form will be selected. There is some evidence that the Homo sapiens brain has decreased slightly in size since it reached its maximum around 200kya. It certainly hasn’t got any bigger. This suggests that our present brain is the minimum size for doing whatever it was doing 200kya, while any further development would incur costs with inadequate nutritional return. That has the converse somewhat condign implication that whatever the H. sap. brain was doing 200kya is the same kind of thing, obviously with different content, that it’s doing today; not the same thing, but the same processes, the same highly complex operations; certainly more complex than being able to follow family and friends relationships in soap operas.
I am suggesting a fundamental re-exploration of what the Homo sapiens brain was and is doing, not in neurological but in out in the world material culture terms.