After the First World War, power shifted to the newly-confident states of the former European Empires such as South Africa and the USA, and the newly emerging Russian Empire of the Soviet Union.

In Europe most social structures were in tatters, and most people were searching for new meanings to their lives. But with the post-war revival of religious belief, and with no new evidence about evolution, evolutionary biologists were confused and low-key. The daily process of picking up the pieces was excruciatingly painful for ordinary people, who were not much interested in science, especially after the recent displays of science on battlefields all around the world. The mood encouraged biologists to react by developing popular topics about human race, plant breeding, and the control of population growth, all of which led to supporting new kinds of social and political extremism.

The former quiet researchers of biological science found themselves as the drivers of new distractions. They were feeding the minds of social reformers, economists and politicians with their own new agendas of psychology, racism, eugenics and agricultural reform. These were distractions away from the main line of evolutionary mechanisms, studies which had been so dull before the war that no-one really missed afterwards. Darwin’s name was rarely used and interest in evolution fell considerably, seeming to be remote from the task of urgently rebuilding a new western world. Instead, the main order of the day for scientists was to look in more detail at the chemistry and physics of molecules in inanimate objects rather than organic life.

Not all the new advances were in the physical sciences, and some became so involved with public and even political scrutiny that their scientific role got lost. Plant breeding, for example, was to be helped by an Imperial Botanical Conference in 1924, sharing ways to grow better crops and even protect the environment. The conference was held in London at Imperial College and it hosted the biologists as part of the victorious British Empire Exhibition. The colonial governments displayed their national heritages and many reconstructed bits of their most interesting natural environments from ecological surveys.

There was economic and political pressure encouraging the Empire to grow more food, and leading specialists from around the Empire had been invited together to debate how to do this. With his military reputation, his new political role and his philosophy of holism Jan Smuts was in his element. It was also the first opportunity for Arthur Tansley to meet the great General.

Unsurprisingly, the two men didn’t hit it off. The big Boer soldier and the wiry intellectual cockney had only their love of plants to share, and that quickly became more of a battle than a balanced exchange. All the talk of botanical surveys left Tansley feeling penniless and without any other support while Smuts had money and fame as well as a free travel pass on the railways. Another of Tansley’s competitors, William Bateson, was also in attendance talking about his strange idea of a genetic map for all the plant resources available in the Empire. Just to finish off a bad month for Tansley, he failed to become the leader of the first botanical survey of the entire Empire.

The meeting had useful seminars on the production of rubber and sugar-cane, how to improve the breeding of apples and coconuts and other crop plants. To help improve expertise and communication it was decided to survey the natural plant and animal resources of every country in the Empire, their ecology and their commercial application. But the meeting didn’t help Tansley to improve this knowledge as he had hoped, while Smuts went away celebrating the lead that South Africa offered with results of their own six years survey of vegetational resources. The meeting had also forced Tansley onto the defensive when it came to decide which country should run the whole project, with South Africa so well ahead in expertise and plans for the future. There was even the slogan ‘holism and evolution’ to promote Smuts’ ecological ambitions, though no-one was aware then what that might involve.

Towards the end of the meeting Smuts invited all the participants to attend another conference that he was hosting in Cape Town two years later, the first overseas meeting of the British Association. It stimulated Smuts to write Holism and Evolution giving an overview of global ecology, “a recognition of the fact that all organisms feel the force and moulding effect of their environment as a whole.” He owed a debt to the American poet Walt Whitman for many of his ideas that nature was at harmony: it “is at bottom a friendly universe, in which organised tolerant co-existance is the rule and destructive warfare the exception.” Smuts then suggested that each animal and plant cell served as a balanced entity with their organism, co-operating with and serving the whole system. Smuts sent a copy of his new book to Winston Churchill who “peered with awe” at the philosophy of holism and ironically in return mailed a copy of his own book The World Crisis.

But 1924 brought an apparently sudden change in direction for Smuts. He had been South Africa’s Prime Minister since 1919 and his party lost the 1924 general election. That gave him time to share the excitement growing within the large group of animal and plant ecologists in the country. There was also time for him to read the latest controversial theory from a German geologist, Alfred Wegener who had come up with the then outrageous suggestion that continents moved apart, their lighter rocks drifting over the heavier mantle beneath. He argued that this very slow movement caused a widening of the Atlantic Ocean because it meant that Africa was moving away from South America and Europe from North America. It was a model that explained the modern distribution of land masses and of the many groups of plants and animals that spread among them. There were also clear connections of geological strata from one side of the Atlantic to the other, but most people thought that Wegener’s idea was too far-fetched to be serious.

This model of moving continents explained a lot of what many South African biologists had been thinking for some time, that their flora comprised species invading from the north and others, such as the Protea family, that were more like plants of Australia and South America. Wegener was suggesting that these regions as well as India had been part of a single continent, since called Gondwanaland, which began splitting up around two hundred million years ago. The migrations appealed to Smuts as well as his colleagues and he soon followed with an idea about human migrations into Africa. “Our Bushmen are nothing but living fossils whose ‘contemporaries’ disappeared from Europe many thousands of years ago. The little pigmy populations that hide in the tropical and sub-tropical forests are the representatives of the long-vanished human past.”

It was one of the first signs in public that Smuts was linking his ideas of plant ecology and holism with the origins of particular human races. Something had pushed his thinking about ecology out of the cosy philosophy of the academic’s arm-chair into a mainstream political policy of race. Not only was he going to use one to justify the other, but he was going to use the honourable reputations of particular scientists to help demonstrate theory behind a new racial policy. First he gathered support from the local scientists and then he used the British Association, which conveniently met in Cape Town in 1929, and the 1930 International Botanical Congress in Cambridge, to gather international support. It was there that Tansley observed with his own brand of understatement that the ideas were “certainly beset with many difficulties which practical ecologists would have to consider and discuss.”

At the Cape Town meeting Smuts had lined up an amazing collection of supporters to help him get across to his electorate and the rest of the world some of his ideas about the migration of human races. The by-then 70 year-old physiologist JS Haldane, Jack’s father, and King George V, were unexpected supporters, while large numbers of South African scientists were loudly approving. Diplomatically on the edge was Julian Huxley who declared “I cannot follow you all the way” while more decisively HG Wells said that black people were “being deprived of educational opportunity and political expression.”

Smuts was a shrewd political operator and he saw to it that the holism and eugenics issues were debated in public at the conference. Although the two ideas appeared at first to be very different, maybe there was something they had in common, and the South African leaders of the Empire botanical surveys wanted to emphasise that. So Smuts was confident that his argument would go down well with the Cape audience and insisted there should be a vociferous opposition to his campaign. Of course, it was so vociferous that the argument would persuade even more people to switch sides to his own cause. Smuts asked the newly appointed zoology professor at Cape Town University, Lancelot Hogben, to speak against his holistic applications. Hogben had just left Lankester’s old chair of zoology at University College London and was known to hold open house to militant black student leaders. He based his attack on Jack Haldane’s recent mathematical proof that natural selection pushes evolution forward gradually. Not only was Hogben highly numerate but he was a practiced experimenter with the toad Xenopus.

This was a re-emergence of the old familiar argument about quality and quantity, the subjective and the objective. It was like what had come between Ray and Newton, Lankester and Galton, and now it was between Smuts and Hogben. But this time, there was a poisoned tag attached to the softer holistic side. At first it seemed their ideas of holism and ecology were certainly compatible and maybe very similar. But while Tansley was a professional academic and a full-time thinker, it seemed that Smuts had other motives. Tansley felt badly let down, deserted by one with whom he had agreed so much even though they had never worked closely. They had never really known one another’s minds.

Hogben was beginning to understand this position in which he found himself and he let rip. The holistic eugenicists should “be concerned with sterilising the instruments of research before undertaking surgical operations on the body politic.” Smuts replied that Hogben was merely a friend of Bertrand Russell. “Russell and I do not see eye to eye on philosophy. He is an atomist while I am a holist”. Hogben stuck it out in South Africa for another year and then returned to London where he found a job at the London School of Economics.