“Why Trust Science?” by Naomi Oreskes.

Photo by Louis Reed 

It was 27 January 1985, the fortieth anniversary of the camp’s liberation. Holding candles, their faces mutilated and bodies disfigured, the survivors of Josef Mengele’s experiments on twins looked out at us from TV sets across the world. They were starting a campaign, asking world governments to find the man known as the angel of death.

Josef Mengele had been trained by an admirer of Adolf Hitler. At university, his favorite subjects were medicine, zoology, physics, philosophy and anthropology, in which he earned a doctorate from Munich University. In May 1943, he arrived at Auschwitz, where he was responsible for deciding who would work at the camps and who would be sent to the gas chambers. Meanwhile, in his laboratory, he carried out some of the most gruesome experiments on human subjects ever undertaken, committing some of the worst war crimes of history.

The procedures were painful—he seldom used anesthetics as he carried out amputations, lumbar punctures and typhus injections. He infected wounds to compare each twin’s reaction. He is alleged to have dissected a one-year-old while the child was still alive. On one occasion, he injected thirty-six children with different colored dyes, to see whether he could change the color of their eyes. Many of them went blind and were later gassed, since he had no further use for them. A Jewish doctor who was an inmate recalled that he once saw samples of eyes on a table: “They each had a number, a letter. The eyes were very pale yellow to bright blue, green and violet.” “They were pinned up like butterflies,” said another witness, who saw an entire wall covered in eyes, “I thought I was dead and already living in hell.”

The idea that inspired Mengele, that people had a moral duty to cultivate the healthiest possible lineage, was centuries old. In Sparta, newborns were inspected by the elders to ensure that only the strong survived, while the weak were left to die. Roman Law stipulated that deformed children be put to death. Auschwitz may have been one of the worst recent examples in public memory, but that wasn’t where it all began.

Eugenics became a global movement in the first half of the twentieth century. The French Society of Eugenics was founded in 1912, with the aim of researching and applying “useful knowledge for the reproduction, conservation and enhancement of the species,” and studying “issues related to the influence of economic, legal and custom status on the value of successive generations and on their physical, intellectual and moral aptitudes.” The Greater Japan Eugenics Society was founded in 1917 and the Japanese parliament passed a eugenics bill in 1940. Several Latin American countries also had societies devoted to eugenics.

In America, eugenicists ascribed troublesome innate tendencies to certain human populations (Italians were violent; Jews were thievish). They also denounced the American declaration of equality as a myth. “Only one objection can be raised against it,” Alfred Schultz wrote in his 1908 book, Race or Mongrel, “that it does not contain one iota of truth.” Between 1907 and 1937, thirty-two states passed laws prescribing compulsory sterilizations. Several books on education and law contained chapters on eugenics, as did many high school and college textbooks. According to the Dean of the University of Virginia Medical School, “the future medical curriculum” should “include a course in sound eugenics.”

Why should we trust science? Because it works, you might answer. But this common response misses some important considerations. Breeders, for example, could choose the qualities of their dogs and horses before scientists understood how heredity worked. In the eighteenth century, as science historian Alberto Martinez reminds us in Science Secrets, experimenters amused and perplexed the public with demonstrations of static electricity, and engineers harnessed electricity to build devices, even though they barely knew what it was and how it worked. In 2017, Australian researchers published a study showing that firehawks carry burning sticks to spread fire, just as indigenous people had long observed—although they had previously always met with skepticism from scientists. Clearly, we can obtain useful and reliable knowledge without science.

Why trust science, then? As Naomi Oreskes argues, generally, when scientists reach a consensus, it is supported by the evidence. Anticipating the objections of those who point to eugenics as a counterexample, she writes,

Insofar as eugenics, like the Limited Energy Theory [which proposed that women should not be allowed to study, as it would imperil their reproductive capacity], was conceptualized and justified as a logical deduction from scientific theory, we cannot simply explain it away as a misuse or misapplication of science. So was there a scientific consensus on eugenics? The short answer is no.

The long answer is, well, it’s not quite so simple. There’s no doubt that a number of prominent scientists became fascinated by eugenics. One such scientist was Albert Einstein. He despised his wife as “a physically and morally inferior person.” She suffered from depression and nervous breakdowns, and he blamed it on her genes. When their son became mentally and emotionally unstable, Einstein attributed it to “the severe hereditary flaw” in his wife’s bloodline. He praised the ancient Spartan practice. “To keep something alive that is not viable beyond the years of fertility is undermining civilized humanity,” he wrote to a friend in 1917. “So it would be urgently necessary that physicians conducted a kind of inquisition for us.”

But the history of eugenics is complex because it involved a broad array of participants and was informed by a wide range of values. In Japan, for instance, eugenicists defended women’s right to education because of their critical roles as mothers. In America, many eugenicists participated in campaigns to eradicate sexual diseases, prohibit alcohol and grant women the vote. In Germany, the Nazis maintained that tobacco threatened health, and promoted several anti-smoking campaigns. Eugenicists did not always agree with each other. In a little known eugenics congress that took place in Paris in 1937, many of those present protested against mandatory sterilizations. Delegates from Argentina, Brazil, Italy, Portugal and Switzerland opposed the US approach: “We have no pretension of being directors of peoples or legislators,” they declared. They supported the goal of improving the quality of the population, but thought it should be achieved through more modest and prudent measures.

We usually think of eugenics as part of a conservative movement, but it was supported by several progressives, too. John Maynard Keynes, for example, called it “the most important, significant and, I would add, genuine branch of sociology which exists.” Socialist economist Sidney Webb asserted that “no consistent eugenicist can be a ‘Laissez Faire’ individualist unless he throws up the game in despair. He must interfere, interfere, interfere!” In his 1915 book, A New Treatment of Economics, Frank Albert Fetter warned that progress was threatened “unless social institutions can be so adjusted as to reverse this process of multiplying the poorest, and of extinguishing the most capable families.”

Yet not all scientists sympathized with eugenics. Social scientist Franz Boas, for example, conducted empirical research to test these ideas, subjecting over 17,000 subjects from reformatories, asylums, parochial and private schools to anthropometric analysis. His results, he reported, showed that “all the evidence is now in favor of a great plasticity” in human traits. When he studied the spread of Europeans across the world, their exploration of the Americas and the rise and fall of their empires, he noted that “historical events appear to have been much more potent in leading races to civilization than their faculty.” The only thing the eugenicists had proven, he concluded, was “how easily the human mind is led to a belief in the absolute value of those ideas that are expressed in the surrounding culture.”

A number of biologists and geneticists also criticized eugenics. While most scientists accepted—and accept—that traits are influenced by both genes and environment, little was known about the role each factor played in human development. “In the face of so much ignorance,” wrote one author, “how can anyone be justified in making sweeping generalizations with reference to these subjects?” Biologists Raymond Pearl and Herbert Spencer Jennings gave public speeches criticizing eugenics on ethical grounds. After visiting statistician Karl Pearson’s laboratory, Pearl commented that Pearson’s lack of biology training often led him to take “an absurd position in regard to biologically obvious things.”

Some geneticists pointed out that, even if the diseases identified by eugenicists were inherited, eugenic policies could not cure them. In the case of recessive diseases, for example, in which the disease is only manifested in those who have inherited two copies of the gene responsible, many people who are heterozygous for the gene may spread the disease unknowingly. Geneticist Reginald Punnet calculated that it would take 90 generations to diminish the incidence of “feeblemindedness” from 1 in 100 people to 1 in 10,000. In other words, eugenicists would require more than two thousand years to make inroads into the problem.

How can the world’s populations be improved? This is the question the Science Service of Washington DC asked a group of experts. They published their joint response on 16 September 1939. The question, they stated, raised “far broader problems than the purely genetical ones,” for “both environment and heredity constitute dominating and inescapable complementary factors in human wellbeing,” and real progress would be impossible “without economic and social conditions which provide approximately equal opportunities for all members of society.” This paper, which was officially entitled “Social Biology and Population Improvement,” but later known as The Geneticists’ Manifesto, was signed by twenty-four geneticists, including J. B. S. Haldane, Julian Huxley and Theodosius Dobzhansky.

Oreskes uses five historical examples to highlight a common theme: the lack of consensus among scientists. The other four subjects she examines are limited energy theory, continental drift, contraceptives and depression, and dental floss. I have chosen to focus on eugenics because this dark chapter in the history of science has been used and abused for political purposes by both right and left. For example, Ross Pomeroy of the Global Warming Policy Forum (a climate change denial think tank) has claimed that eugenics is an instance of how “scientific consensus leads to mass murder.” Oreskes notes that

these claims are misplaced: scientists did not have a consensus about eugenics or continental drift. Social scientists, socialist geneticists, and some mainstream geneticists critiqued eugenics; the rejection of continental drift was a distinctly American affair. (Europeans for the most part withheld judgment, which is a different thing.) Nor was there a consensus over the Limited Energy Theory, the Pill or dental floss … A key finding from historical inquiry into these episodes, then, is that in all of these cases there was significant, important, and empirically informed dissent within the scientific community.

Contra popular beliefs and simplistic narratives, the history of science repeatedly shows that most scientists, most of the time, have been honest and objective in their pursuit of truth. Take the case of drapetomania. Invented by American physician Samuel Cartwright in 1881, this disease was diagnosed as the reason why some negroes attempted to escape their masters. In her book Superior, Angela Saini tells us that Cartwright’s nosology was “patently rooted in the desire to keep slaves enslaved, to maintain the status quo in the American South.” Cartwright was a distinguished physician, but that does not mean that everyone took his ideas seriously. Many physicians complained that the evidence he provided was very weak. Drapetomania never became a standard diagnosis in American psychiatry. One anonymous contemporary writer, in the Buffalo Medical Journal, quipped that “the same cautious induction and logical accuracy” led him to believe that drapetomania resulted from the synchronization of the patient’s body with the magnetic north.

Oreskes does not deny that scientists may be wrong, but she argues that individual scientists make mistakes mostly when they ignore certain lines of evidence. One case that she doesn’t mention, but which fits this pattern, concerns the removal of homosexuality from the Diagnostic and Statistical Manual of Mental Disorders. Backed by psychiatrists (many of whom were themselves homosexual and belonged to an unofficial group called the GayPA), activists challenged the idea that homosexuality was a mental disease. They presented the Kinsey reports, which suggested that the prevalence of homosexuality was higher than previously believed, and a study by psychologist Evelyn Hooker, who compared homosexuals’ and heterosexuals’ IQs and showed that homosexuality was not associated with psychological disturbances. The panel were shocked. Many had never heard of the studies, and, when the Nomenclature Committee held their next symposium, they agreed to remove homosexuality from the DSM.

So why were they unaware of the relevant studies? One psychologist recalls that, at the time, finding relevant medical literature

would involve numerous trips to the library, copying articles in journals, checking out books, lugging the whole business back to [the] office, and poring over it before writing (on a typewriter or by hand) a first draft. Now the same feat of reviewing the literature can be accomplished while sitting in front of a computer and accessing all the same sources and finding many more of them, all a few clicks away. The mind is more easily expanded in academia today than it was in the past.

Co-authorship was rare. In 1900, only around 7% of papers in the natural sciences were co-authored. By 1960, around 60% were. By 2000, the average number of authors per paper in the medical sciences was seven. Co-authorship is now the norm, rather than the exception, in many sciences. Thus, such oversights are far less likely today.

On the basis of studies showing that more diverse teams tend to yield better outcomes, both in qualitative metrics, such as creativity, and quantitative metrics related to performance, Oreskes posits that diversity of values, methods, evidence and scientists is a precondition of a firm consensus. She isn’t the first to suggest this. Boaz Miller has argued that a diverse community may pose new questions, identify limitations, suggest alternative interpretations of extant data and open new lines of evidence and inquiry, thereby facilitating the formation of an evidence-based consensus. Diversity of methods and evidence has long been considered necessary. In fact, this is one of the features that distinguishes science from pseudoscience. As Mario Bunge argued long ago, while most pseudosciences remain isolated from other fields, sciences are always interconnected and their study domains often overlap.

Trust in scientific consensus is not the same as blind faith. A scientific consensus doesn’t tell us what we should do—it only points out what we can’t ignore. These days, such trust is a rare commodity. Consider the current pandemic. In a recent survey, 70% of Democrats said that they trust the World Health Organisation, by contrast with only 25% of Republicans, 86% of whom put more trust in President Trump. This is a symptom of a broader malaise that has characterized Trump’s administration, during which scientific agencies such as the Environmental Protection Agency (EPA), the National Park Service (NPS) and the US Fish and Wildlife Service (USFWS) have cited political pressure as one of the greatest barriers to science-based decision-making. Last year, Brazilian president Jair Bolsonaro announced a freeze on 42% of the funds earmarked for the country’s Science and Communications Ministry. Six scientific societies warned that it would “take many decades to rebuild the country’s science and innovation capacity.” Mexico’s left-wing president Andrés Manuel López Obrador has cut the country’s science budget and appointed a man with no medical or epidemiological training as head of the Institute of Health and Wellbeing.

Likewise, it’s not uncommon to hear that regulations designed to protect human health and the environment are too costly to be implemented—although they often end up costing less than expected, and the benefits outweigh the costs. For example, the US Acid Rain Program was forecast to cost $2.4–5 billion per year. It actually cost less than $1 billion. The Montreal Protocol was forecast to cost an annual $65 billion by 2020: instead, benefits exceeded costs by a factor of more than 30:1. The environment and the pandemic aren’t unrelated concerns. Many of those who have downplayed the risks posed by climate change also downplay the risks of coronavirus. Coronavirus risk denial overlaps with climate change denial.

What are some issues on which there is a scientific consensus? There’s a great deal of evidence to show that tobacco causes lung cancer, that there is no risk threshold for alcohol consumption, that water fluoridation is both safe and necessary, that glyphosate (the active ingredient of most common herbicides) poses no risk to human health. There’s a scientific consensus that there has been real, anthropogenic climate change, and that coronavirus is deadlier than the common flu.

What you choose to do with this information is up to you. But you could start by reading Oreskes’ inquiry. You won’t be disappointed.