This year marks the 200th anniversary of the birth of Charles Darwin. It is also 150 years since the publication of the book that made him world famous, indeed notorious – On The Origin Of Species By Means Of Natural Selection.
For a man who consciously cultivated scholarly obscurity and whose real claim to our attention is as a natural scientist, Darwin’s image is extraordinarily contested.
On the one hand, we have the benign sage portrayed in David Attenborough’s recent BBC special, Charles Darwin And The Tree Of Life. On the other, you have the Darwin who is under constant attack from the Christian right.
The Guardian recently trumpeted an opinion poll commissioned by the religious think-tank Theos. According to this “only” half the British population think that Darwin’s theory of evolution by natural selection is definitely or probably true.
Some 22 percent accept either creationism or “intelligent design” – in other words, they think that God directly created all the complex variety of living beings.
This is one reason why Darwin’s legacy is disputed. It has come under fire from those who campaign for “intelligent design” to be taught on equal terms with evolutionary theory at schools.
This is presumably why Attenborough devoted so much of his programme to carefully and vividly demonstrating how subsequent scientific research has confirmed the theory of evolution.
But Darwin is also suspected by many on the left. They fear that his ideas have served to legitimise a succession of reactionary ideologies.
These start with “Social Darwinism” in the 19th century – the attempt by various ideologues to prove that biological evolution justifies capitalist competition and the imperialist domination of “inferior” races.
Then, much more recently, there has been the development of sociobiology. This involves reducing the behaviour of human beings in society to the demands supposedly put on them by their genes.
The reactionary implications of this kind of approach are well brought out by Richard Dawkins’ portrayal of people as “lumbering robots” driven unconsciously by the “selfish genes” that use them as means for their reproduction.
None of this has much to do with Darwin. Social Darwinism was developed before The Origin Of Species was published, notably by the liberal sociologist Herbert Spencer, who coined the slogan “survival of the fittest”.
It usually relies on the very different, indeed incompatible, conception of evolution developed earlier by the French zoologist Jean-Baptiste Lamarck.
Nor was Darwin a racist. Adrian Desmond and James Moore, the authors of an outstanding biography of Darwin, have just published a new study, Darwin’s Sacred Cause.
They document how disgusted he was when confronted with slavery in South America during his five-year voyage on HMS Beagle in the 1830s.
Darwin developed the idea of evolution by natural selection after returning to England. In his notebooks he attacked the idea that black people belonged to a different species from whites: “Do not slave holders wish to make the black man other kind? From our origin in one common ancestor we may be all netted together.”
Indeed, at the core of Darwin’s theory is the idea that, not just human beings, but all living organisms, are “netted together” through the evolutionary process.
The Origin Of Species seeks to establish two basic claims. The first is that evolution, what he calls “descent by modification”, happens.
The Christian orthodoxy of Darwin’s day held that all the different kinds of plants and animals were “special creations”. In other words, God designed all the different species as we know them today.
The implication was that nature has no history. But by the middle of the 19th century this had ceased to be credible.
The development of geology revealed that the earth itself had a history, and also exposed, often buried deep in rock strata, the fossilised remains of extinct plants and animals.
It was an obvious conclusion that these were the ancestors of the present day array of plants and animals. But if living organisms evolved – developed and changed from one kind into another – how did this happen?
Enter Darwin’s second great claim, the theory of evolution by natural selection itself. This explained how evolution worked on the basis of three assumptions.
The first is that, according to Darwin, “many more individuals of each species are born than can possibly survive… consequently, there is a frequently recurring struggle for existence”. An organism’s chances of survival will depend on how well adapted it is to its environment.
Second, the individual members of a species differ slightly from one another. Moreover, they are able to pass these variations on to their offspring. Third, some of these differences will allow the organisms that possess them, in a given environment, to reproduce better than others.
What do these assumptions imply? Take a population of organisms belonging to the same species and living in a common environment.
The descendants of those organisms that develop variations that fit them better to that environment will become, over time, a larger proportion of the population.
Or, as Darwin puts it: “Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relations to any other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring.
“The offspring, also, will thus have a better chance of surviving, for, of the many individuals which are periodically born, but a small number can survive. I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection.”
One of the most important things about natural selection is that variations do not develop because they may fit the affected organism better to its environment. A creationist would say, for example, that the human eye was designed by God to allow us to see.
For Darwin, the eye develops through the “very slow, intermittent action of natural selection” – an almost endless process of minor modifications in different organisms each of which adapts the organism better to its environment.
The reason why each variation takes place is nothing to do with any conscious or unconscious purpose of increasing the organism’s chances of survival.
We now know that variations are caused by small, random changes in the genetic code – the strings of DNA modules that govern the manufacture of proteins as plants and animals develop – when they are passed on from parents to offspring. It is purely a matter of good or bad luck whether or not a variation helps or hinders the organism cope with its environment.
So evolution is blind, according to Darwin. It is the constant interplay between genetic mutations and environmental changes that leads to the proliferation of different species each representing a specific niche in the struggle for survival.
Darwin took the idea of the “struggle for existence” from the writings of Thomas Robert Malthus, the early 19th century economist. Malthus argued that there was a natural tendency for the human population to grow faster than the production of food. This made the division of society into rich and poor inevitable.
Darwin’s great contemporary Karl Marx commented: “It is remarkable how Darwin recognises among beasts and plants the English society of his day with its division of labour, competition, opening up of new markets, ‘inventions’ and the Malthusian ‘struggle for existence’.”
Darwin in fact said he used the idea of a struggle for existence in “a large and metaphorical sense”. Thus he argued that it may pit animals or plants not necessarily against each other, but against their environment:
“There must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life.”
Despite his criticisms of Darwin, Marx wrote that The Origin Of Species “is very important and serves me as a natural-scientific basis for the class struggle in history”. Indeed, at Marx’s funeral in 1883, his great friend and collaborator Friedrich Engels compared the two men.
He was right to do so. Marx dethroned all the kings and queens, the great men and women of history. He showed how societies change as a result of the conflicts that develop in the way in which they organise production.
Darwin dethroned God. He allowed us to see all the variety and richness of life as nothing to do with divine purpose, as the result of a blind process of natural selection. As he puts it in the final paragraph of The Origin Of Species, “There is grandeur in this view of life.”