The descent of Charles Darwin

This year marks 150 years since Charles Darwin’s The Descent of Man was presented to the public in 1871, his follow up to the Origin of Species published 12 years earlier.

Descent was the second of his books outlining his idea of evolution by natural selection and was overtly aimed at tying mankind into the natural evolutionary past.

It was a revolutionary text much of which still resonates today. It also contains ambiguities and contradictions that have been present in evolutionary science ever since.

Naturalist

The context in which Darwin was writing in 1870 was crucial to understanding this book. This was the height of the Victorian industrial and imperialist era.

In the intervening years since Origin the world had seen the American Civil War, fought over the issue that Darwin had felt a keen sensitivity to – slavery.

The whole Darwin Wedgwood family had been anti-slavery campaigners throughout the 19th Century.

By 1870 Bismarck was on the march and war in Europe was about to erupt. In Britain the industrial wealth was fuelling the growth of the British Empire – the ‘civilising mission’ was very much afoot around the world.

Also in the intervening years between the Origin and the Descent Darwin had built up a legion of naturalist followers who sent him observations from around the world describing the behaviour of plants and animals.

Revolutionary

He had maintained a dialogue with the scientific circles emanating from London.

This included public papers and ongoing correspondence with friends such as evolutionist Thomas Huxley, botanist Joseph Hooker, geologist Charles Lyell, anatomist George Mivart, his cousin Francis Galton as well as his co-discoverer of natural selection, Alfred Russell Wallace.

This circle was small but it was intense for Darwin and much of The Descent of Man was written in response to disagreements he was having with them, particularly Mivart and Wallace.

Outside of this circle there was still much opposition to evolution as an idea from both the religious and political establishment.

Darwin himself spent most of his adult life treading a very thin line between respectable Victorian gentleman and revolutionary naturalist and writer. Nowhere is that more apparent than in this book.

Creation

The main point that Darwin felt compelled to make in The Descent of Man was that humans had very much come about by a vast historical gradual process of natural selection and had gradually ‘descended’ from primate ancestors and earlier versions of hominids.

He had agonised over this issue because he knew that it simultaneously undermined the creation ideas that underpinned established religion as well as destroying man’s nobility above the natural animalistic world.

Within his circle he had been dismayed by the refusal of his old friend Charles Lyell and his new friend Wallace to accept that mankind fell under the purview of evolution.

They maintained that the mind of man, his brain power, had to be a special creation separate and superior to animals.  

Rereading the book now I was struck by what an achievement of writing it is.

Natural

Long passages read like a stream of consciousness about the natural world reporting and interpreting his received information from around the world.

In each chapter he politely explains the issue he is responding to: “As Mr Wallace has argued...” or “According to Professor Owen....” and then proceeds to destroy their arguments with reasoning and facts deployed with equal politeness.

It is partly a work of ecology, tying man into natural systems and lauding the ability and complexity of other animals.

He pays tribute to the social system of ants, the intricacy of spider’s webs, the group life of chimpanzees and there is a lengthy exposition of the sex life of Crustaceans.

It is a work of reality in the natural world. There are not hypothetical experiments or the reductionism of modern science. This is placing man within the real system of natural life on Earth.

Reproduction

The first half of the book is a step by step destruction of the arguments that kept man out of the evolutionary system.

The second half of the book is a lengthy exposition of sexual selection, firstly in other species and then showing how sexual selection has affected the development of humans.

It is revolutionary. He is overt about religion being the result of a superstitious instinct and compares the faculties of mind between man and other animals.

Any differences are of ‘degree’ not from separate creation and his passages about the brain anticipate modern neuroscience.

Sexual selection was the other side of natural selection for him – the reproduction side where Origin had been the survival side.

Fittest

Talking so matter-of-factually about the pervasiveness of sex was a shock to the prudish Victorians and sexual selection has remained an idea that even scientists have struggled with since.

Darwin was in tune with natural selection because he had meditated upon it for many years. The natural system was one where traits would be retained through survival and then reproduction and anything facilitating either of these things would very likely be retained.

A whole range of physical and behavioural traits have been retained across all species that seem to be ‘ornamental’, that serve no useful function, except that they facilitate sex and through doing so will be reproduced.

This is still a contentious idea today in science and has needed determined modern advocates such as Geoffrey Miller, Holly Dunsworth and Richard Prum.

The language of Descent is fascinating. Darwin rarely uses the word evolution. In the intervening years Herbert Spencer had coined the phrase ‘survival of the fittest’ and Darwin refers to it once - and tentatively.

Living

The modern evolutionary terms of ‘adaptation’ and ‘fitness’ are absent. Darwin uses ‘adapted’ in the past sense, in that species become adapted due to preservation of variations and as in the origin stresses that the ‘conditions of life’, environmental pressure, are important.

He emphasises the importance of ‘social instincts’ in man and shows how these exist in other species.

In describing the evolution of man his is the language of an ecosystem arising alongside a myriad of other amazing animals: “The difference in mind between man and the higher animals...certainly is one of degree and not of kind.”

And later: “If any single link in the chain had never existed, man would not have been what he now is. We may, with our present knowledge, recognise our parentage; nor need we feel ashamed of it.

"The most humble organism is something much higher than the inorganic dust under our feet; and no one with an unbiased mind can study any living creature, however humble, without being struck with enthusiasm at its marvellous structure and properties.”

Rage

And yet, there is Chapter 5 of The Descent of Man: On the Development of Intellectual and Moral Faculties during Primeval and Civilised times.

Here, Darwin writes in the explicit tones of social Darwinism, the pernicious hierarchical view of evolution that was pursued in his name by imperialists, industrialists, white supremacists and eugenicists and would lead to huge historical forces being unleashed in the twentieth century.

This chapter now makes for tough reading for Darwinists like myself as he laments the over-reproduction of ‘inferior’ peoples and explicitly portrays the superiority of ‘civilised’ man over ‘savages’.

“The nations of Europe now so immeasurably surpass their former savage progenitors and stand at the summit of civilisation.”

These ideas are certainly wrong. I would still argue that this has to be seen in the context of its time. His cousin Francis Galton had only published his ideas of ‘hereditary genius’ the year before in 1869 and the philosophies of Auguste Comte and Herbert Spencer were all the rage.

Reductionist

There was an assumption that the ‘civilisation’ of Western Europe was superior to the rest of the world and the rest of the world just needed to be conquered and educated.

This is an ambiguity that runs right through The Descent of Man. On the one hand Darwin is dragging a reluctant mankind down among the animals and on the other is keeping civilised man as “the wonder and glory of the Universe”.

It explains why this book has been difficult for advocates of evolution and students will always be pointed to the more ecological and theoretical Origin of Species. His respectable Victorian reputation was constantly grappling with his revolutionary ideas and in Chapter 5 of Descent the Victorian wins over.

This ambiguity and contradiction has carried on till this day. The crude reading of natural selection as the survival of the fittest is still a powerful summary of evolution in wider culture.

Even among evolutionary and biological science there is often an assumption of progress. The history of science since Darwin has been dominated by reductionist investigation, trying to prove in ever greater detail, how evolution has occurred.

Technological

In many ways the ecological approach to nature partly arose in the 1960s and 70s as the antidote to reductionist biological science.

In recent years there has been a confluence as the truth of man-made climate breakdown becomes manifest. The same ambiguity that Darwin portrayed is at work.

Humans are an amazing species with amazing capabilities to influence and control life on Earth and yet we are a part of a natural system that is much larger than us.

The ambiguity is still being played out today. Modern evolutionist Steven Pinker outlines a convincing argument for progress not far from the Victorians idea of 'civilisation’ in his book Enlightenment Now but was castigated by environmentalists such as George Monbiot for not taking the environmental challenge seriously.

Many scientists working in environmental and biological science believe that environmental problems can be solved by technological solutions.

Conditions of life

Many ecologists and naturalists believe that science has disrupted natural systems that have evolved over millions of years and we will run into trouble through not respecting nature and evolution.

It’s still a battle between man's providence over nature versus humanity's humility within nature.

It’s a subtle but important philosophical difference that is having a real world impact and reconciling the two may be important to our future. This has started to happen.

Environmentalism has become more scientific and Earth systems science has grown in universities around the world.

Evolutionary biology is becoming more aware of what Darwin referred to as the conditions of life. As an example the journal Nature instituted its sub-journal: Ecology and Evolution in 2017.

Legacy

Most scientists increasingly accept that the environmental challenges need changes in human actions and behaviour as well as technological solutions. This is not an either/or, it’s an attack on both fronts.

Modern science continues to amaze but it does need to be tempered with a dose of humility towards nature. In evolutionary science some of the language is not helpful.

The continual use of ‘fitness’ betrays a tendency towards the misleading ‘survival of the fittest’ and there is much conflation around adapt, adapting, adapted and adaptation.

Saying that humans can adapt to their circumstances is a social Darwinist or even Lamarckian idea. It’s an important difference to say humans became ‘adapted’ in the past sense by a gradual honing by the environment over millions of years and puts humans in a more humble context within nature.

We need a more subtle understanding of evolution in which there is more of a demarcation between the process of evolution and the legacy of evolution.

System

The gene is the mechanism by which evolution has occurred but the legacy is unique, complex, functioning individual organisms with an uncertain future delicately tied into their surroundings and their social and physical context. 

The Anthropocene, this era in which we have realised that human arrogance had become self destructive to the planet that we live on, should be a wakeup call for scientists, politicians, and indeed for people everywhere.

If Darwin were here I would laud him for his courage and original revolutionary thought but I would also show him the calamity that ideas of human superiority have had in the 150 years since he wrote The Descent of Man.

Perhaps we need to pursue a post-Darwin ecological approach to evolution, one that takes man off of his pedestal, brings a confluence to the science, where all people are valued in their great diversity, and a realisation that we have been an overly disrupting influence in the Earth’s evolved life system.

The Author

Stuart Hobday is a PhD researcher in Philosophy at UEA, is the founder of Norwich Science Festival and the author of Encounters with Harriet Martineau.