Science, Religion, and Human Inequality: Racism, Eugenics, and Euthanasia

Abstract

Over the past two or three centuries, some influential scientists and theologians have claimed the mantle of science to promote human inequality. They have achieved this by arguing that science provides support for racism, eugenics, and even euthanasia. Scientific racists not only claimed that science demonstrated the inequality of the human races, but also argued that the extermination of allegedly inferior human races was a natural, inescapable process. The eugenics and euthanasia movements have claimed that people with some disabilities are inferior, and thus, should be restricted from reproducing or even killed. The Nazi regime committed horrific atrocities in the name of these allegedly scientific ideas. Since the mid-twentieth century, most people in Western societies have rejected racism and compulsory eugenics and euthanasia. However, some prominent intellectuals are once again insisting that science demonstrates human inequality, and they do not consider killing those deemed inferior to be immoral. As Western culture becomes increasingly secular, religious voices are having less impact in countering these views.

1. Introduction

Yuval Noah Harari is not a scientist, but a very influential historian. However, in his 2015 bestselling book, Sapiens: A Brief History of Humankind, he appeals to science, especially evolutionary biology, to attack the claim in the US Declaration of Independence that “all men are created equal.”1 According to Harari, “the idea that all humans are equal is also a myth … According to the science of biology, people were not ‘created.’ They have evolved. And they certainly did not evolve to be ‘equal.’” Harari then sums up his inegalitarian position: “So here is that line from the American Declaration of Independence translated into biological terms: We hold these truths to be self-evident, that all men evolved differently, that they are born with certain mutable characteristics, and that among these are life and the pursuit of pleasure” (Harari 2015).

How did Harari form the idea that science had disproved human equality and human rights, too? This paper will address this question by tracing key biological scientists’ historical views about human nature and their resultant cultural impact on how we value others. Unfortunately, over the past few centuries, some influential scientists and religious leaders have claimed scientific sanction for inegalitarian philosophies. By the late nineteenth century, many leading biologists, anthropologists, and medical professors were insisting that racism and discrimination against people with disabilities were solidly based on settled science. They proclaimed that eugenics, the program to improve human heredity by controlling human reproduction, was scientific. The eugenics movement, which included some influential progressive/liberal ministers, promoted compulsory sterilization of those people deemed inferior. The more radical wing of the eugenics movement endorsed involuntary euthanasia for people with disabilities. These scientists and ministers disparaged anyone insisting on human equality as hopelessly backward and/or tradition-motivated.

Fortunately, after World War II, most scientists rejected scientific racism and eugenics—especially support for involuntary measures—as misguided. They recognized that these ideas were not scientific, so they often referred to them as “pseudo-scientific.” However, in many cases, these mid-twentieth-century and later scientists did not understand how prominent these ideas were among the earlier scientific community—including some of the most prominent scientists of that time—who insisted that these ideas were scientific. However, by the late twentieth and early twenty-first centuries, some scientists began insisting once again that science sanctions human inequality. They were usually not espousing racial inequality; nonetheless, like Harari, they were endorsing inegalitarianism.

2. Scientific Racism

In the eighteenth century, some scientists, such as the German anatomist Johann Friedrich Blumenbach, began investigating and classifying the various human races. However, Blumenbach, like most of his contemporaries, believed in monogenism, i.e., that all humans had a common origin, which was the dominant position in the Christian tradition. Blumenbach also thought that races had differentiated primarily because of environmental conditions, such as climate (Mosse 1985).

During the early nineteenth century, many biologists and anthropologists shifted to polygenism, the idea that human races were so different that they must have had different origins. Furthermore, many scientists began to claim that races were not only varied physically but also intellectually and behaviorally. This intellectual change reflected the decline of religious influence and the increase in secularization. The historian Nancy Stepan claims that because of this, “By 1850, racial science was far less universalistic, egalitarian and humanistic in its outlook than it had been in 1800” (Stepan 1982). This change reflects a significant shift from a traditional biblical view of race, where there is no distinction between Greek and Jew, barbarian, Scythian, slave, or free before God (Colossians 3:11). Claims from the antebellum South or elsewhere that the “mark of Cain” (Genesis 3:11) or the “curse on Ham/Canaan” (Goldenberg 2005) (Genesis 9:24–27) justified the enslavement or subordination of certain races are now recognized as classic examples of ripping verses out of context. Ancient Israel was commanded to treat the foreigner the same as the native, always remembering that they had been slaves in Egypt (Leviticus 19:33–34). Moreover, slavery in ancient times was not based on race or ethnicity but on conquest or debt (California Newsreel 2003).

The British anatomist Robert Knox reflected this secular inegalitarian outlook in his 1850 book The Races of Men. He declared therein that it is “simply a fact” that “human character, individual and national, is traceable solely to the nature of that race to which the individual or nation belongs.” Because of that, Knox asserted, “Race is everything: literature, science, art, in a word, civilization, depend on it.” Knox claimed that the race he called the Saxon race, which included many Britons, “is about to be the dominant race on the earth,” because of its superior racial qualities. Knox also stated, “I feel disposed to think that there must be a physical and, consequently, a psychological inferiority in the dark races generally.” Because of his belief in racial disparity, Knox exulted that the white races would eventually exterminate the dark races. In his book, Knox also peddled anti-Semitic and anti-Gypsy stereotypes—such as their alleged unwillingness to labor—claiming these were scientific observations of their racial characteristics. Knox, thus, claimed scientific sanction for belief in racial inequality and, moreover, that these racial inequalities would lead to the extermination of the allegedly inferior races (Knox 1850).

At the first meeting of the Anthropological Society of London in 1863, James Hunt, the founder and president of the society, made a presentation “On the Negro’s Place in Nature.” Hunt claimed that his findings were scientific and based on impartial observations, but in reality, they reflected the prejudices of many Europeans of his day. He asserted “that the Negro is inferior intellectually to the Europeans,” and because of this difference, “there is a far greater difference between the Negro and European than between the gorilla and chimpanzee.” Like Knox, he thought European imperialism was a natural consequence of racial differences. He stated, “Everywhere we see the European as the conqueror and the dominant race, and no amount of education will ever alter the decrees of Nature’s laws.” Hunt believed that racial characteristics were fixed biological properties and non-malleable features (Hunt 1863–1864; see also Mosse 1985, pp. 70–71). Like Knox, Hunt fostered a view of scientific racism that would become more prominent among many scientists by the close of the nineteenth century.

Terence Keel argues that these racist views are anchored in Christian intellectual history and were absorbed into science through European cultural prejudices (Keel 2018). We would suggest the opposite: European cultural prejudices were imported into Christian intellectual history by conveniently ignoring the verses cited above (as well as many others). Sadly, some religions do incorporate racism, such as the Hindu caste system; however, this shows the very broad, if not universal, human tendency to establish “us/them” worldviews in which one’s own ethnicity (or nation, political party, profession, alma mater, or sports team) deserves the highest status. Critically, “scientific facts,” not religious arguments, and polygenism, not biblical monogenism (which was increasingly ridiculed), were being used to justify racial differences and superiority.

Charles Darwin’s theory of evolution would also promote racism among biologists and anthropologists in the late nineteenth century.2 Darwin’s theory emphasized biological inequality, which was necessary for evolution to occur. The first two chapters of his On the Origin of Species (1859) dealt with biological variation, stressing the differences that develop within species. Darwin did not discuss human evolution in Origin (except for a very brief comment at the close of the book), because he knew that human evolution from animal ancestors would be extremely controversial. However, in 1871, he published The Descent of Man, which applied the principles of variation and natural selection to the human species.

Darwin outlined three main objectives of The Descent of Man: (1) to investigate whether humans are descended from animals; (2) to explain the process of human evolution; and (3) to describe “the value of the differences between the so-called races of man” (C. Darwin 1981, vol. 1, p. 3). Of the seven chapters in The Descent of Man that deal with human evolution, one is titled “On the Races of Man.” Racial themes are present in many other chapters, too. Thus, racism played a central role in Darwin’s theory of human evolution.

Darwin tried to demonstrate that some human races were closer biologically to the apes than others in order to convince his contemporaries that humans had evolved from some kind of simian species. Darwin thought that Europeans had evolved further away from apes than the black Africans, for instance. While admitting that the distance between present-day humans and simians seemed great, Darwin alleged that the gap would increase as the “savage races” were exterminated. This rested on Darwin’s view that the black Africans or Australian aborigines were currently the closest races to the gorilla, which he considered the highest of the ape species (C. Darwin 1981, vol. 1, p. 201). In the chapter “On the Races of Man,” Darwin confirmed his belief that races differ considerably, both physically and in their mental capacities. For this reason, he considered races to be distinct subspecies (C. Darwin 1981, vol. 1, pp. 216, 227).

In the second chapter of The Descent of Man, “Comparison of the Mental Powers of Man and the Lower Animals,” Darwin stressed the huge variation between humans in their mental capacities by pointing out racial differences. He stated the following:

Nor is the difference slight in moral disposition between a barbarian, such as the man described by the old navigator Byron, who dashed his child on the rocks for dropping a basket of sea-urchins, and a Howard or Clarkson; and in intellect, between a savage who does not use any abstract terms, and a Newton or Shakspeare [sic]. Differences of this kind between the highest men of the highest races and the lowest savages, are connected by the finest gradations. Therefore it is possible that they might pass and be developed into each other.

(C. Darwin 1981, vol. 1, p. 35)

Darwin considered Howard and Clarkson, leading British abolitionists, the epitome of moral goodness. They were, of course, Europeans—as Newton and Shakespeare were, too—and Darwin identified them as “the highest men of the highest races,” in contrast with the “lowest savages.” Thus, Darwin advanced his evolutionary theory by claiming that Europeans were intellectually and morally superior. This is tragically ironic because during Darwin’s time, these allegedly morally superior Europeans were exterminating the supposedly morally inferior natives in the Americas, Australia, and elsewhere. Most people today would not consider genocide an activity of people with superior morality, as Darwin did.

Genocide or racial extermination played a prominent role in Darwin’s theory of human evolution. As he explained earlier in On The Origin of Species, all organisms are locked in an ineluctable struggle for existence, which is most intense within each species because they compete for the same niche. Darwin thought that racial competition was a prime manifestation of the human struggle for existence. In The Descent of Man, he stated, “At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate and replace throughout the world the savage races.” (C. Darwin 1981, vol. 1, p. 201). A few years later, he reiterated this position in a letter to a colleague, stating that the “more civilised so-called Caucasian races have beaten the Turkish hollow in the struggle for existence. Looking to the world at no very distant date, what an endless number of the lower races will have been eliminated by the higher civilised races throughout the world” (F. Darwin 1902).

Many Darwinists in the late nineteenth and early twentieth centuries embraced human inequalities, including scientific racism, as an integral part of their worldview. Some, such as Ernst Haeckel, a leading evolutionary biologist in late nineteenth-century Germany, were even more racist than Darwin. While Darwin upheld the unity of the human species, Haeckel claimed that human races were so divergent they should be classified as ten separate species in four distinct genera. Haeckel also minimized the gap between humans and apes, claiming that “the differences between the lowest humans and the highest apes are smaller than the differences between the lowest and the highest humans.”3 Based on his racist views, Haeckel did not think people of allegedly lower races had much value either. In his 1904 book, The Wonders of Life, he discussed racial inequalities in a chapter entitled “The Value of Life.” The main point in that chapter was that not all humans have the same value. He stated, “The value of life of these lower wild peoples is equal to that of the anthropoid apes or stands only slightly above them” (Haeckel 1904).

One of the leading scientists in the United States in the early twentieth century, Henry Fairfield Osborn, a professor of anatomy at Columbia University and also a leading paleontologist, was also a proponent of scientific racism. Osborn, who was also president of the American Museum of Natural History in New York City, wrote the preface to Madison Grant’s book, The Passing of the Great Race, which promoted scientific racism. Grant was not a scientist, but he had many close friends who were scientists, and he founded the Bronx Zoo in 1895. Osborn insisted in his preface that Grant’s method “is the correct scientific method of approaching the problem of the past.” Osborn also gave his stamp of approval to Grant’s racism by stating, “Thus conservation of that race which has given us the true spirit of Americanism [here he means whites descended from Europeans] is not a matter either of racial pride or of racial prejudice; it is a matter of love of country, of a true sentiment which is based upon knowledge and the lessons of history rather than upon the sentimentalism which is fostered by ignorance.” Thus, Osborn contended that Grant’s views on race were “based upon knowledge,” while those rejecting his position on race were steeped in “sentimentalism” and “ignorance” (Osborn 1919).

The Bronx Zoo, still under the leadership of Madison Grant, aroused considerable controversy in 1906 when it displayed the African pygmy, Ota Benga, among its primates. Although protested by conservative black and white religious leaders in New York, the zoo and many scientists justified this move by claiming that it would help the public better understand biological evolution. This was based on the belief that black Africans were more closely related to apes than were white Americans and Europeans.4

By the 1930s and thereafter, scientific racism declined considerably among Anglo-American scientists. However, in Germany, scientific racism remained dominant in biology and anthropology until the collapse of the Nazi regime in 1945. Biologists and anthropologists promoting racism as scientific significantly contributed to the Nazi worldview. Eugen Fischer, for instance, was a leading anthropologist long before the Nazis came to power in 1933. He became a professor of anthropology at the University of Freiburg in 1918. In 1927, he was appointed director of the Kaiser Wilhelm Institute of Anthropology, Human Heredity, and Eugenics, which was one of the most prominent positions in Germany for an anthropologist. In a lecture published in 1910, Fischer outlined racial ideas that later became central in Nazi ideology. In that talk, Fischer insisted that races have different mental abilities. He claimed that the Nordic race is the highest race because it is the primary creator of culture (Fischer 1910). Throughout his career, Fischer articulated the view that human races were formed through Darwinian processes. In an essay from 1912 to 1913 on “Races and Racial Formation,” he stressed that racial variations are the basis for human evolution, and natural selection determines which races will survive and which will go extinct (Fischer 1912–1913). Another leading anthropologist in Germany, Otto Reche, was appointed professor at the University of Leipzig in 1927, thus before the Nazis came to power. He embraced Nordic racism and believed that races were engaged in a Darwinian struggle for existence.

Hitler and the Nazi regime insisted that their racist ideas were scientific, and many leading scientists—not only German ones—supported this contention. Fischer and Reche cooperated with the Nazi regime. Fischer helped formulate Nazi racial policy by participating in government-appointed committees to draft legislation. He lent support to Nazi racism by participating in the program to sterilize Germans who had been fathered by black African troops (who had been part of the French occupation forces after World War I) (Pommerin 1979). Reche taught racial theory to Nazi organizations and at Nazi conferences. He also offered to help the Nazi regime identify the racial makeup of individuals in Nazi-occupied Poland.5 Based on their understanding of scientific racism, Hitler and the Nazi regime committed some of the worst atrocities in world history by murdering millions of people based on their racial classification.6

After the collapse of the Nazi regime in 1945, scientific racism declined in Germany, as had already happened in the Anglo-American world. For the most part, scientific racism only continued to exist in the late twentieth century in fringe groups, such as neo-Nazis and white nationalists.7 With a few exceptions, such as the Nobel Prize-winning geneticist James Watson, scientists rejected the idea that science advances racial inequality.

Unfortunately, strongly racist views persisted in many southern conservative Christian denominations well into the 1960s Civil Rights Movement struggles, illustrating the strong influence of culture on one’s exegesis and avoidance of relevant biblical passages. Conservative Christians today are much more racially egalitarian, given the recognition of the total lack of biblical support and, secondarily, scientific warrant for discrimination (Keller 2020).

As distasteful as these racist views and their supposed scientific justifications are to contemporary scientists and people today, we are not citing individual extreme positions, but scientists who were the founders of and leaders in their scientific disciplines and the academy in the 18th to early 20th centuries, as their prestigious positions, classic publications, and titles illustrate. Sadly, they shaped and represented “consensus science” in their lifetimes, as demonstrated by their ability to influence government policies. In an era of colonialism, the idea that “some people are more evolved than others” fit well with Western thinking. While there surely were some scientists who disagreed with these views for religious and non-religious reasons, their opposition is not mentioned by these influencers. There appears to be virtually no dialog or discussion questioning them in scientific circles, as the naysayers mentioned by these influencers are only from conservative religious groups. It was not until the horrors of Nazi Germany shocked the world and biological determinism was deconstructed in the 1970s by Richard Lewontin and others (Edge et al. 2022) that scientific racism became pseudo-scientific.

3. Eugenics

Human inequality was a central feature of the eugenics movement, which aimed to improve human heredity. Many of the leading figures in the eugenics movement were scientists or physicians, and they claimed that their views were based on solid science. By the 1890s and the first decades of the twentieth century, many—maybe most—biologists in the US, UK, and Germany embraced eugenics.

Though many eugenicists believed in scientific racism, the primary thrust of eugenics was to try to rid the world of people with disabilities, especially mental disabilities. Eugenicists regularly referred to disabled people as “inferior,” “having lesser value,” “unfit,” “lower,” “useless,” “burdens to society,” “degenerate,” “defective,” and even “worthless.” For example, Ignaz Kaup, a professor of social hygiene at the University of Munich in the early twentieth century, wrote an article in 1913 on “What Do the Inferior Elements Cost the State and Society?” He warned against false compassion for the “inferior,” since “our healthy offspring have the right to be protected from decay through those who are genetically pestilent, and every progressive nation has the duty to reduce the ballast of the costs of inferiority.”8

Kaup’s attitude was not unusual among eugenicists, who often used similar disparaging terminology, as well as terms such as “pests,” “parasites,” and “vermin,” to describe people with disabilities. The prominent German geneticist Erwin Baur, a fervent supporter of eugenics, at the close of his widely used text on genetics, drew distinctions between people who are inferior and superior (Baur 1914). The German neurophysiologist Kurt Goldstein wrote a book on eugenics, in which he argued that population increases are beneficial, but only if “every individual has value.” This implies that some individuals have no value, a point Goldstein made explicit immediately thereafter, stating, “The increase of worthless individuals is indeed rather harmful” (Goldstein 1913). Similar expressions about the inferiority and even worthlessness of some individuals—usually the disabled—abound in the writings of biologists, psychiatrists, and physicians around 1900. In 1912, a German medical professor, Hugo Ribbert, reflected this trend when he stated, “The care for individuals who from birth onwards are useless alike mentally and physically, who for themselves and for their fellow-creatures are a burden merely, persons of negative value, is a function altogether useless to humanity, and indeed positively injurious” (Ribbert 1918). Ribbert’s comments reflect contempt for any individuals who do not measure up to his own standards.

Francis Galton, the founding father of the eugenics movement, wrote in his memoirs, “The publication in 1859 of the Origin of Species by Charles Darwin made a marked epoch in my own mental development, as it did in that of human thought generally” (Bulmer 2003). Darwin’s Origin convinced him of the important role that variation and heredity played in biological species, including humans. In 1865, he published his first essay on heredity, “Hereditary Talent and Character,” in Macmillan’s Magazine, followed by a book, Hereditary Genius, in 1869. Galton had a significant impact on the science of heredity in the late nineteenth century. He won many over to his view that people deemed superior or talented should reproduce as prolifically as possible, while those deemed inferior should be discouraged from reproducing. In an article published in 1873, for instance, he argued that inferior people who procreated should be deemed enemies of the state, and—even more ominously—he opined that they “have forfeited all claims to kindness.” Galton and his disciples believed that controlling human reproduction would biologically improve the human species (Gillham 2001).

In 1905, the German physician Alfred Ploetz founded the Society for Race Hygiene, the first eugenics organization in the world. He recruited the two leading Darwinian biologists in Germany, Ernst Haeckel and August Weismann, as honorary presidents. Ploetz founded a eugenics journal and co-edited it with Ludwig Plate, a zoologist. Most of the members of the Society for Race Hygiene were scientists or physicians. Ploetz stressed biological inequality between humans and continually criticized Christianity, humanitarianism, and democracy for their egalitarian ideals (Ploetz 1895). When he founded the Society for Race Hygiene, he hoped to recruit members only from those whom he considered biologically superior. However, this was impractical because he lacked the ability to measure biological superiority objectively. Nonetheless, members were supposed to have a medical exam before marrying to ascertain if they were fit to reproduce (Ploetz 1911). Another leading figure in the German eugenics movement, the physician Wilhelm Schallmayer, also dismissed egalitarianism with scorn. “Making the unequal equal,” he wrote, “can only be an ideal of the weak” (Schallmayer 1903).

The leading figure in the early stages of the American eugenics movement was Charles Davenport, a zoologist who became a professor at Harvard University in 1892 and at the University of Chicago in 1899. In 1904, Davenport transferred to the Station for Experimental Evolution at the Cold Spring Harbor Laboratory to pursue eugenics research. He founded the Eugenics Record Office there in 1910 to compile genealogical records that traced people’s hereditary traits. Like other eugenicists, he stressed human inequality and the need to rid the world of those he considered biologically inferior. He stated in 1909 that “society must protect itself[;] as it claims the right to deprive the murderer of his life so also it may annihilate the hideous serpent of hopelessly vicious protoplasm” (Paul 1995). Despite this inflammatory language, Davenport was not promoting killing people, but rather controlling reproduction to “annihilate” the allegedly dangerous biological traits of people with congenital disabilities. Davenport’s work on human heredity was so highly regarded by other scientists that he was elected to the National Academy of Sciences in 1912 (Spiro 2009, p. 131).

Davenport’s friend, Madison Grant, was just as strong a supporter of eugenics as of scientific racism. In The Passing of the Great Race he stated, “A rigid system of selection through the elimination of those who are weak or unfit—in other words, social failures—would solve the whole question in a century, as well as enable us to get rid of the undesirable who crowd our jails, hospitals, and insane asylums.” He explained further that this did not mean harming disabled individuals, but it could be accomplished by sterilizing them. Thereby, the “weaklings” and “worthless race types” could be eliminated from future generations (Grant 1936). In 1926, Grant held a meeting in his home with several others, including Osborn, to found the American Eugenics Society (Spiro 2009, p. 180).

In some jurisdictions in the United States and Europe, eugenics proponents convinced lawmakers that eugenics had scientific sanction, so they should introduce public policy to eradicate disabilities in future generations. One of the most popular measures was compulsory sterilization of people with disabilities. When laws for compulsory sterilization were being debated in various states in the US, many scientists, physicians, and psychiatrists supported such legislation. Their efforts were aided by progressive/modernist Protestants such as the Reverend Oscar McCulloch of Indiana, who saw eugenics as supporting the social gospel and as a scientific means of keeping the sins of the fathers from being passed on to their children (see Exodus 34:7, 20:5, and Deuteronomy 5:9) (Zenderland 1998). With this combination of religious and scientific support, in 1907, Indiana became the first state in the US and the first jurisdiction in the world to pass a law that allowed for compulsory sterilization for eugenics purposes. Through clever American Eugenics Society strategies, such as sponsoring “eugenics sermon contests” to spread the word to progressive, eugenics-minded church leaders and their congregations, eventually over half the states in the US passed laws for the compulsory sterilization of criminals and/or people with mental disabilities. Christine Rosen documents how these religious leaders “genuinely believed that eugenics would increase human happiness” (p. 184) but also observes how they “embraced modern ideas first and adjusted their theologies later… And it was when these self-identified liberal and modernist religious men abandoned bedrock principles to seek relevance in modern debates that they were most likely to find themselves endorsing eugenics. Those who clung stubbornly to tradition, to doctrine, and to biblical infallibility opposed eugenics and became, for a time, the objects of derision for their rejection of this most modern science” (Rosen 2004, p. 5). By the 1960s, when the scientific errors of eugenics were recognized, and most of these laws were set aside, approximately 60,000 Americans—approximately half of them in California—were sterilized without their consent. In Europe, several countries, including all the Scandinavian ones, introduced compulsory sterilization by the 1930s (Paul 1995, ch. 5).

The most radical implementation of eugenics policies in the world occurred in Nazi Germany, for Hitler and his regime were fanatical in their pursuit of the biological improvement of the human species (see Weikart 2009). In the summer of 1933, the Nazi regime issued a decree calling for the compulsory sterilization of people with mental and congenital physical disabilities. They applied this so zealously that approximately 350–400,000 Germans were sterilized in the twelve years of the Nazi regime. This comprised approximately one out of every two hundred Germans. The Nazi regime also promulgated laws to encourage those deemed good hereditarily to have as many children as possible.

As with scientific racism, eugenics declined after World War II. One of the ideas underpinning scientific racism and eugenics was biological determinism. By the mid-twentieth century, it was being challenged, especially by environmental determinism as well as traditional Christian religious ideas such as free will. Thus, biological determinism declined, making racism and eugenics intellectually and theologically untenable. Moreover, the radical Nazi eugenics program produced a backlash against racism and eugenics. Furthermore, by the mid-twentieth century, Western culture was increasingly stressing individual freedom, including in relation to reproduction, and this flew in the face of compulsory measures, such as sterilization. Finally, by the late twentieth century, the disability rights movement fought against the idea that people with disabilities were second-class citizens and had lesser value than other people.9

Some today may wish to dismiss these supposedly scientific supports for eugenics as the view of a few individual extremists. Nevertheless, we have striven to show that these views were espoused by influential scientists who were the founders of and leaders in their scientific disciplines and the academy in this era, as well as by leading progressive Protestant ministers. These leaders shaped and represented “consensus science” at this time and influenced government policies. While there surely were some scientists who had reservations for non-religious reasons, their opposition is not mentioned by these influencers, who only call out conservative religious leaders as their opponents.

4. Euthanasia

Some influential scientists also played a key role in the advent of the euthanasia movement in the late nineteenth century, a movement which was far more consistently resisted by religious groups than racism and eugenics. Beginning in 1870, public discussion began in Europe about euthanasia, which included assisted suicide (which is how the term is usually used today) and the involuntary killing of people with disabilities. Many secular advocates of euthanasia in the late nineteenth century saw it as a means to promote eugenics. They denied that all humans have equal value, so they did not think it was objectionable to kill those deemed inferior.10

Ian Dowbiggin, the historian who has provided the best overview of the euthanasia movement in America, explains what influenced its emergence in the nineteenth century: “Trends such as eugenics, positivism, social Darwinism, and scientific naturalism had the effect of convincing a small yet articulate group in the early twentieth century that traditional ethics no longer applied to decisions about death and dying” (Dowbiggin 2003, p. 2). These secularizing tendencies changed people’s mindset about the meaning of life and death, and thus helped give impetus to the euthanasia movement.

One secularizing tendency—Darwinism—played a particularly powerful role in helping undermine the Judeo-Christian sanctity-of-life ethic. Dowbiggin highlights this by claiming, “The most pivotal turning point in the early history of the euthanasia movement was the coming of Darwinism to America” (Dowbiggin 2003, pp. 2, 8). Nick Kemp, the foremost historian of the British euthanasia movement, concurs with Dowbiggin, writing, “While we should be wary of depicting Darwin as the man responsible for ushering in a secular age we should be similarly cautious of underestimating the importance of evolutionary thought in relation to the questioning of the sanctity of human life.” (Kemp 2002, p. 3, quote at p. 19). A leading expert on the early history of euthanasia in Germany, Hans-Walter Schmuhl, found a similar development in the German euthanasia movement. He explains, “By giving up the conception of the divine image of humans under the influence of the Darwinian theory, human life became a piece of property, which—in contrast to the idea of a natural right to life—could be weighed against other pieces of property.” (Schmuhl 1987, pp. 18–19, quote at p. 106).

The German Darwinian biologist Haeckel was one of the earliest individuals publicly to promote killing people with disabilities. In 1870, in the second edition of his book on biological evolution, Natürliche Schöpfungsgeschichte (Natural History of Creation), he backhandedly promoted infanticide for babies with serious disabilities. He stated the following:

If someone would dare to make the suggestion, according to the example of the Spartans and Redskins, to kill immediately after birth the miserable and infirm children, to whom can be prophesied with assurance a sickly life, instead of preserving them to their own harm and the detriment of the whole community, our whole so-called “humane civilization” would erupt in a cry of indignation.

(Haeckel 1868, pp. 152–55; quote at p. 155)

This did not overtly call for killing disabled babies, but it strongly implied that he supported it. In his 1904 book, Lebenswunder (The Wonders of Life), Haeckel admitted that he supported killing infants and adults with disabilities. He claimed that people with hereditary mental illnesses had not developed beyond the stage of animals, so it was morally permissible to kill them, just as we kill animals. Some people, he insisted, have lives that are “completely worthless.” He suggested that a panel of physicians should determine which cases were serious enough for involuntary euthanasia (Haeckel 1904, pp. 21–22, 134–36).

In the late nineteenth century, the euthanasia movement was considered rather radical, but it was going to gain steam in the early to mid-twentieth century. In 1937, Charles Francis Potter, a former Unitarian minister who founded the First Humanist Society of New York in 1933, established the Euthanasia Society of America (ESA). Though he was not a scientist, his humanist worldview, as reflected in the Humanist Manifesto of 1934, which he signed, claimed that science was the proper guide for one’s life. Potter also recruited some leading scientists to join the ESA, such as the geneticist Clarence Cook Little, who served as president at the University of Maine and the University of Michigan in the 1920s, and the biologist Oscar Riddle.11 When Riddle was featured on the cover of Time magazine on 9 January 1939, the brief caption with his photo on the cover proclaimed, “Evolutionist Riddle. ‘All men are created unequal.’” Like many other eugenics advocates, Riddle rejected human equality, and this anti-egalitarianism infused the euthanasia movement.

Another prominent scientist in the mid-twentieth century who promoted involuntary euthanasia for people with disabilities was the Nobel Prize-winning biologist Alexis Carrel. In his 1935 book Man, the Unknown, Carrel explicitly promoted using gas chambers to kill some people whom he called “inferior individuals” (Carrel 1935). Carrel was featured on the cover of Time magazine twice in the 1930s. An article on “The Right to Kill” in Time on 18 November 1935, reported, “The Rockefeller Institute’s famed Nobel Prizeman Alexis Carrel declared that sentimental prejudice should not obstruct the quiet and painless disposition of incurables, criminals, hopeless lunatics.” (Time Magazine 1935).

In Germany, public debate over involuntary euthanasia erupted in 1920, when the psychiatry professor Alfred Hoche and the legal scholar Karl Binding published their controversial book, Permitting the Destruction of Life Unworthy of Life. In this book, Binding and Hoche not only called people with mental disabilities “life unworthy of life,” but Binding claimed they are “not only absolutely worthless, but existences with negative value” (Binding and Hoche 1920). In his autobiography, Hoche explained that his view of nature shaped his vision of killing people he considered inferior. He stated that in nature,

the continued existence of the species is everything, the individual is nothing; she [nature] carries on an immense waste of seeds, but the individual, after she has given it—the mature one—opportunity to pass on its seed to the future, she heedlessly lets die; it is for her purposes without value.

(Hoche 1935)

Binding and Hoche’s book faced significant criticism initially, but it began to make the idea of euthanasia—voluntary and involuntary—respectable among scholars and physicians.

We do not know if Hitler read Binding and Hoche’s book, but his attitude and the mindset of many of his Nazi colleagues mirrored their perspective. In a 1937 Nazi documentary film, Opfer der Vergangenheit (Victim of the Past), the commentator stated, “In nature everything weak unfailingly perishes. In the last few decades we have sinned terribly against this law of natural selection. We have not only preserved the life [of the weak], but we have even allowed them to reproduce. All this misery could have been prevented, if we had previously prevented the reproduction of the hereditarily ill.” The film also insisted that people with mental illnesses “are lower than any animal.”12 Though most Germans in the 1930s and 1940s rejected involuntary euthanasia, the Nazi regime found several scientists and medical professionals who enthusiastically assisted them in their program to kill people with disabilities. Hitler’s personal physician, Karl Brandt, had studied under Hoche and embraced Hoche’s views about euthanasia. Under Brandt’s leadership, the Nazi regime began systematically killing people with congenital disabilities in 1939. By the close of World War II, they had murdered approximately 200,000 Germans and tens of thousands of others in occupied lands.13

After World War II, most Europeans and Americans recoiled against euthanasia, partly in response to the horrors of the Nazi regime’s atrocities. However, by the 1980s and thereafter, support for euthanasia would grow in some segments of European and American society. The Netherlands, Belgium, and Switzerland led the way in legalizing euthanasia in Europe, and Oregon pioneered assisted suicide in the United States. Unlike the Nazi euthanasia program, most of the support for euthanasia today is for assisted suicide and/or voluntary euthanasia.

However, some intellectuals are still promoting involuntary euthanasia for individuals with serious disabilities, and like their predecessors in the nineteenth century, they use scientific rationales to justify their inegalitarian position. One of the leading bioethicists of the late twentieth and early twenty-first centuries, Peter Singer, includes Darwinism as one factor in his view that humans are not intrinsically valuable. Singer’s position is complex, arguing for an “equal consideration of interests” and concluding that speciesism is immoral, since both animals and humans feel pain (Singer 1975). Instead of species membership, he argues that characteristics such as self-awareness, rationality, and future-oriented preferences should be used in evaluating the moral status of a person (Baranová 2025). Singer notes that Darwin “undermined the foundations of the entire Western way of thinking on the place of our species in the universe.” He complains that even though Darwin “gave what ought to have been its final blow” to the “human-centered view of the universe,” the commonly held view that humans are special has not disappeared. Singer is now trying to provide the deathblow to the sanctity-of-life ethic (Singer 2000). For instance, he supports selective abortions and utilitarian infanticide based on the idea that babies are not equal to adult humans. He states, “It’s a simple fact that a three-year-old human has pretty much the same self-awareness, rationality and capacity to feel pain as an adult ape. So they should be given equal moral consideration” (Hari 2004). Hence, according to Singer, not all humans are equal because they do not have the same cognitive abilities (Baranová 2025).

The philosopher James Rachels agreed with Singer about the effect of Darwinism on the value of human life. His book, Created from Animals: The Moral Implications of Darwinism (Rachels 1990), argues that Darwinism—a position he supports—undermines the Judeo-Christian sanctity-of-life ethic. “I shall argue,” Rachels stated, “that Darwin’s theory does undermine traditional values. In particular, it undermines the traditional idea that human life has a special, unique worth.” He applauded Darwinism for discrediting the outmoded “idea of human dignity.” Like Singer, Rachels uses these Darwinian ideas to support a view of human inequality that approves of abortion and euthanasia.14

Peter Singer, with the support of many scientists, such as Richard Dawkins, Jared Diamond, and Jane Goodall, began the Great Ape Project, which aims to extend the moral circle to apes. Their 1993 declaration demands that apes be included in the “community of equals” that includes humans, chimpanzees, gorillas, and orangutans. According to their declaration, these great apes should all be granted some moral rights, including the right to life, the right to individual liberty, and freedom from torture. However, despite their high-minded rhetoric, they do not mean that everyone in these four species would be equal; as in George Orwell’s Animal Farm, some animals are more equal than others. Singer and his colleagues base moral rights on an individual’s “capacities,” so unborn humans and mentally disabled humans are not included in the moral community. Because of this, in their opinion, these people can be killed (Cavalieri and Singer 1993). Consequently, they promote human inequality.

In general, Christians, Jews, and Muslims have mostly been opposed to all varieties of euthanasia. They view every human life as having dignity and value because it is a gift from God, and no person has the authority to kill an innocent person, even if that person wishes to die or is disabled. They apply these principles to the embryo and fetus as potential persons, and thus, oppose abortion since this similarly judges the individual as worthless. However, some liberal Christian and Jewish denominations, following secular culture, are pro-abortion and affirm the individual’s freedom of choice regarding the means and timing of death (Saint Joseph’s University Institute of Clinical Bioethics n.d.; Pew Research Center 2013). Moreover, the overwhelming majority of world religions oppose the killing of disabled people, arguing instead that they need special protection and care (BBC 2014; ReligionFacts 2015). The extreme views of Singer regarding terminating the disabled appear to be echoed only in the Unitarian Universalist Church, where “loss of dignity” is equated with “physical or mental disability” (Ostling 2021).

5. Present Trends

Advances in biotechnology and medicine are giving rise to what some are calling the “new eugenics,” where the secular marketplace offers life-and-death choices to individuals in an ethical and moral vacuum (McDaniel 2023). In vitro fertilization, which enables child sex selection and screening for hereditary disabilities, is widely available, and genetic manipulation to cure genetic defects is on the horizon. As these technologies develop further, they offer the promise of “designer babies.” Married couples and individuals are being offered choices that should involve spiritual reflection, but which often do not because so many (even religious) people today are more influenced by popular culture and media than by any religion. While some of these advances can be viewed as curative, and thus as medical benefits, many fall into the category of “playing God” in shaping the life of another individual. In a secular-to-nominally religious culture equipped with technology driven by the profit margin, there is no venue to consider and to guide these eugenic practices. Moreover, euthanasia today, under the label of “Medical Assistance In Dying” (MAID) or assisted suicide, can project the messages that “you are better off dead than alive,” “you should not be here,” and “you are worthless” to those facing challenging issues, but not fatal diseases (Favaro 2022), and can be motivated by the desire to reduce the costs of socialized medicine, a justification that feels very similar to Nazi “useless eater” rationales (Zhu 2022; Coelho et al. 2023). Cultural/peer norms, expectations, and subtle “fully medically informed” pressure can motivate women to abort babies with Down’s syndrome, for example, as is happening in Iceland (Klucznik and Slepian 2018; Burke 2021), although the government notes that there is no legal pressure to do so, and they officially respect the dignity of the disabled (Embassy of Iceland in London 2018). Thus, science today is generating powerful tools, while religion is marginalized, with no other alternate moral/ethical virtue leaders and standards beyond Hollywood, social-media influencers, naturalism, and radical individualism.

6. Conclusions

Over the past couple of centuries, some influential scientists, theologians, and other non-scientists have claimed the mantle of science to justify various forms of human inequality. Some of the most egregious examples are scientific racism, eugenics, and euthanasia. It is humbling and distressing to realize that these views were espoused, not by isolated extremist individuals, but by many of the scientific and religious thought leaders and consensus-makers who shaped the culture of their day. While most people in our society today have come to reject scientific racism and compulsory forms of eugenics and euthanasia, some prominent scholars, such as the historian Yuval Harari mentioned in our Introduction, are still claiming that science provides support for some forms of human inequality. Human equality or inequality is not a scientifically tractable concept, as it involves moral judgments that are fundamentally religious in nature. However, with the decreasing influence of religion in Western society to provide an external moral compass, we increasingly appear to be living in “let every man do what is right in his own eyes” (Judges 21:25) times, where science is called upon to justify stances that are often based on one’s own prejudices, convenience, and/or worldview.