Interest in Charles Darwin’s theory of evolution among those on the left stretches back a long way. Karl Marx wrote of Darwin’s Origin of Species, “Although it is developed in the crude English style, this is a book which contains the basis in natural history for our views.”
Marx’s appreciation of Darwin was ahead of its time. Darwin’s central idea – the theory of natural selection – was not generally accepted until the 1930s. By then the discovery of genes, which encode information about an organism and allow it to be passed down to subsequent generations, provided a mechanism through which natural selection could take place.
But widespread acceptance of natural selection did nothing to quell debate about the workings of evolution. Stephen Jay Gould’s contribution to these arguments, which helped spark the so-called “Darwin wars”, was among the most important.
Professor Steven Rose, himself a noted neurologist and science writer, co-edited a new collection containing 45 of Gould’s greatest essays. “The scientific core of the book is Gould’s contributions to the critique of a fundamentalist neo-Darwinism,” said Rose.
“The fundamentalist position has been most clearly expressed by scientist Richard Dawkins. It says that in evolution there is a unit of selection – the gene. Genes are what he calls ‘replicators’ and the organism is what he calls the vehicle – a passive carrier for the replicators.”
Scientists believe that humans have over 20,000 genes, some other organisms have more, some fewer. Genes are subject to random mutations producing novel characteristics in an organism. According to modern accounts of natural selection, this variation gives different organisms a greater or lesser chance of surviving and reproducing, passing on some of their genetic make-up to the next generation.
“Natural selection acts on organisms,” said Rose. “But fundamentalist neo-Darwinism says that the phenotype [the physical make-up and behaviour of an organism] is exactly the product of its genes. For them, it’s the gene that is the key unit of selection.”
It was this fundamentalist view that Gould, along with other scientists such as Richard Lewontin, set out to challenge. “Gould’s position is that the gene is not the only unit of selection,” said Rose. “After all you can’t select one gene because the way an organism creates itself depends on the interplay of hundreds of thousands of genes.” Selection, argued Gould, might operate at the level of an organism, a local population of organisms or of a whole species.
A second major theme in Gould’s work is expressed in a famous paper, included in the new collection, which he presented with Lewontin. The paper, entitled The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme “made the people who heard it at the Royal Society absolutely apoplectic with anger. But it was a brilliant paper,” said Rose. Like so many of the essays in the collection, this paper uses an example drawn from Gould’s vast knowledge of areas beyond the natural sciences to make its point.
In architecture, a spandrel is the triangular space that is created between two arches. The spandrels of the San Marco Cathedral in Venice, are an architectural by-product of mounting a dome on four arches – even if they subsequently appear to have been central to the intentions of the architect. “The design is so elaborate, harmonious and purposeful that we are tempted to view it as the starting point of any analysis, as the cause in some sense of the surrounding architecture”, wrote Gould and Lewontin. “But this would invert the proper path of analysis.”
Gould’s point, developed through this analogy, is straightforward. According to Rose, “Not everything we see around us is an adaptation. Some things may be accidental, some may be the consequence of adaptations for quite different processes.
“Gould also coined the term ‘exaptation’. He used this to describe how adaptations for one purpose could be pressed into service for another. The best example is feathers, which evolved to provide heat protection for reptiles but then became extraordinarily efficient and useful for flying.”
Contingency – the role of chance events – plays a key role in Gould’s work. “If you go back again to fundamentalist neo-Darwinian theory, and again Dawkins is the best exponent of this, there is an idea that there is a finite number of solutions to the problems posed by evolution,” said Rose. “You start with a primeval soup and the conditions of the primitive earth, and you will end up, pretty much automatically, with people.
“Gould argued that, in fact, there is a hell of a lot of accident in all this. You could not predict how things will turn out simply by looking at the starting point. He made an analogy with winding the tape of history back and letting it run forward again – it’s in the highest degree unlikely, he said, that things would emerge in the same way. For example, the asteroid that wiped out the dinosaurs and made space for an explosion of different mammals was an accident.”
As well as arguing that selection operates on a number of levels, and giving greater scope to contingency, Gould put forward a powerful argument about the tempo of evolutionary change. His theory of punctuated equilibrium is probably his most widely known contribution to evolutionary theory.
“The debate about punctuated equilibrium goes right back to the period after the publication of Origin of Species,” said Rose. “Darwin insisted that evolution had to be gradual, taking place through infinitesimally small steps. Many of Darwin’s allies said, ‘It can’t happen like that. We must be able to make leaps, otherwise small changes will simply be wiped out.’ There were a lot of fights among evolutionists over this question.
“This wasn’t really resolved until the neo-Darwinian synthesis of the 1930s, in which the consensus became that, because you have genetic mutations, small evolutionary changes could be preserved across generations. This opened up the possibility of slow Darwinian evolutionary change. What Gould and Niles Eldredge pointed out in their punctuated equilibrium theory is that if you look at the fossil record over hundreds and thousands of millions of years you have stasis – no change in the fossil form.
“Then over a relatively short evolutionary space of a few hundred thousands of years, or a few million years, there are dramatic changes to the fossil record. In a sense, it depends what timescale you regard as short and what you regard as long. So it became a semantic fight in a number of ways. But what this masks is another fight about the relationship between genes and phenotypes.
“If you are getting constant changes in genes at a fairly fast rate – such as those produced by naturally occurring radiation – and yet the fossil structure, which reflects the phenotype, doesn’t change, it tells you there isn’t a one-to-one relationship between the gene and the phenotype. The organism has properties that mean it can compensate for genetic change and it will end up pretty much the same. But, eventually, if there is a sufficient accumulation of genetic change, you will get a rapid change in the phenotype-speciation [the formation of new species] to use the evolutionist term.
“The essence of the theory of punctuated equilibrium seems to me to be unproblematic. The reasons people became so angry about it are more to do with politics and ideology than anything else.”
Some of the attacks on punctuated equilibrium consisted of “opponents suggesting it was a Marxist plot – an attempt to translate social revolution into the biological world”, said Rose. The charge of introducing Marxism into his work was one that Gould would certainly have rejected. However, he was associated, especially in his early life, with many left causes. He was involved in the anti-Vietnam war movement in the US and played a major role in the radical Science for the People group. During his time as an undergraduate student in Leeds, he picketed racially segregated dance venues.
His commitment to anti-racism is one point at which Gould’s scientific views and politics met, and this is reflected by a series of essays in the new collection. According to Rose, “He had a major impact in destroying the basis for so-called scientific racism.”
But it is not simply the scientific contributions Gould made within his field, or his political sympathies, that make the new collection a joy to read. Now, more than ever, science is the subject of huge interest, as attested by large numbers of popular science books and television programmes. But it is also the subject of a great deal of fear and trepidation.
Gould’s essays shine with a desire to make science relevant and accessible, but also exciting and entertaining. Aside from the essays directly concerned with Gould’s work, the reader will discover a number of gems. “How The Zebra Gets Its Stripes” attempts to answer the question, “Is a zebra a white animal with black stripes or a black animal with white stripes?” “The Darwinian Gentleman at Marx’s Funeral: Resolving Evolution’s Oddest Couplings” considers why one of only nine mourners at Marx’s funeral was E Ray Lankester, a “stout and imposing relic of Victorian and Edwardian biology”.
Science, for Gould, also appears to be something very human. In “The Median isn’t the Message”, written shortly after he was diagnosed with terminal cancer, he uses his illness to explain, with typical eloquence, some basic principles of statistics. Even the most tragic of circumstance is marshalled in the attempt to educate and fascinate. This collection is a fitting tribute to a great practitioner and populariser of scientist.
The Richness of Life – the Essential Stephen Jay Gould, edited by Steven Rose and Paul McGarr, is published by Jonathan Cape, £25. It is available from Bookmarks. Phone 020 7637 1848
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