“An age of science is necessarily an age of materialism,” wrote Hugh Elliot early in the last century. “Ours is a scientific age, and it may be said with truth that we are all materialists now.”
One does not have to look far to discover the continued accuracy of Elliot’s assessment. Scientific materialism—the claim that everything in the universe can be fully explained by science as the products of unintelligent matter and energy—has become the operating assumption for much of American politics and culture. We are repeatedly told today that our behaviors, our emotions, even our moral and religious longings are reducible to some combination of physical processes interacting with our environment.
In 1943, British writer C. S. Lewis wrote prophetically about the dangers of scientific materialism in a small, penetrating volume titled The Abolition of Man. There Lewis warned that “if man chooses to treat himself as raw material, raw material he will be: not raw material to be manipulated, as he fondly imagined, by himself, but by mere appetite…in the person of his dehumanized Conditioners.”
My book Darwin Day in America explores the impact on American politics and culture of the materialistic abuse of science Lewis warned about so many years ago. Contrary to its title, the book is not just about Darwin. It is about how modern science—a very good thing—has been misappropriated by scientific elitists who want to offer a materialistic explanation of every part of human culture.
Darwin comes into the story because his theory of unguided evolution based on natural selection and random variations offered a seemingly convincing explanation for how materialism could actually work. That is why someone like Richard Dawkins praises Darwin for making “it possible to be an intellectually fulfilled atheist.” But Darwinism is only one part of the larger problem, and scientific materialism reaches far beyond Darwin.
The effort to apply scientific materialism to American public policy began in earnest more than a century ago with high hopes. Around the turn of the 20th century, defenders of scientific materialism began issuing increasingly lofty claims about how the understanding of the material world offered by science could be enlisted to solve all the problems of human society. The same scientific advances that produced inventions like the steam engine and medical breakthroughs like the germ theory of disease were also supposed to supply the basis for eliminating a host of social ills ranging from poverty and crime to unproductive workers.
Writing in the journal Science in 1903, J. McKeen Cattell, president of the American Society of Naturalists, argued that previous scientific achievements in helping man subjugate the natural world were just a foretaste of the future power science would bestow on man to control human nature:
The nineteenth century witnessed an extraordinary increase in our knowledge of the material world and in our power to make it subservient to our ends; the twentieth century will probably witness a corresponding increase in our knowledge of human nature and in our power to use it for our welfare.
Charles Eliot, president of the American Association for the Advancement of Science (AAAS), similarly predicted in 1915 that “biological science” would open the door “to the prevention as well as cure of [the]… bodily defects” that caused such antisocial behaviors as murder, robbery, forgery, and prostitution. “These are all biological problems; and the progress of biological inquiry during the past fifty years is sufficient to afford the means of solving on a large scale these fundamental social problems.”
Such comments embodied perfectly the optimistic vision offered by scientific materialism at the dawn of the last century. During an era when science seemed to be uncovering the material basis of all human problems, it was widely believed that science with a capital “S” could lead to the transformation of society, bringing about greater human freedom, dignity, and happiness in the process. In short, scientific materialism was supposed to be a great engine of human progress in politics and culture.
It was not. Human nature was not reformed; crime did not disappear; and scientific materialism did not usher in a new age of liberty, equality, and fraternity. Instead, the excesses of scientific materialism have continued to influence American public policy in at least five important ways.
One influence of scientific materialism on American public policy has been the elevation of technocracy—rule by scientific expert—over democracy. Since science was supposed to be the only true source of objective information about the world, proponents of scientific materialism logically concluded that scientists—not the general public or their elected representatives—should be the ultimate arbiters of public policy.
At its core, this message was profoundly anti-egalitarian and anti-democratic. Speaking before the Second International Congress of Eugenics in 1921, Alleyne Ireland declared that current conditions had rendered America’s original form of government, established by the Constitution and the Declaration of Independence, “utterly unsuitable.” America’s Founders believed that “governments derive their just powers from the consent of the governed,” and they set up arrangements “designed with a view to making abuse of power difficult.” But in an age when government must increasingly provide a wide range of social services, society could no longer afford to rely on government by non-experts. Ireland stated that it was “imperative…that the omnipresent activity of government should be guided by the light of scientific knowledge and conducted through the instrumentality of a scientific method.”
The claim that society should place its faith in scientific experts rather than ordinary citizens or elected officials was a common refrain in public policy debates influenced by scientific materialism. To be sure, few were as blunt as Ireland in directly attacking the Constitution or demanding that scientists govern ordinary citizens. Yet in controversy after controversy, the underlying message was unmistakable. Whether the issue was education or welfare or crime, members of the public were urged to place their trust in the findings of scientific experts rather than in their own core beliefs or the views of political and religious leaders. Science dictated the replacement of punishment with treatment in the criminal justice system, the enactment of forced sterilization in the welfare system, and the substitution of supposedly “value-free” information from sex researchers for traditional moral teachings about family life in public schools. In each of these areas, the claim was made at least implicitly that scientific expertise should trump other sources of knowledge, including ethics, philosophy, tradition, religion, and common sense.
Of course, there is much that can be said in favor of the authority of scientific expertise in modern life. In an increasingly complex and technologically driven world, the need for scientific input on public policy would seem obvious. Since many policy questions today arise in such science-based fields as medicine, transportation, and ecology, why should politicians and voters not simply defer to the authority of scientific experts in these areas?
Although this line of reasoning exhibits a surface persuasiveness, it ignores the natural limits of scientific expertise. Scientific knowledge may be necessary for good public policy in certain areas, but it is not sufficient. Political problems are preeminently moral problems, and scientists are ill equipped to function as moralists. C. S. Lewis warned about this drawback of technocracy in the 1950s. “I dread specialists in power, because they are specialists speaking outside their special subjects,” Lewis wrote. “Let scientists tell us about sciences. But government involves questions about the good for man, and justice, and what things are worth having at what price; and on these a scientific training gives a man’s opinion no added value.”
For example, wildlife biologists may be able to provide policymakers with information about which species are in danger of extinction. Perhaps they can also predict some of the costs of a species’ extinction to biodiversity. But they have no more authority than anyone else in determining whether a particular endangered species is more valuable than the jobs that may be lost trying to save that species from extinction. Politics is largely about ranking and reconciling competing goods; but the ranking of goods involves questions of justice and morality, and as Lewis pointed out, “a scientific training gives a man’s opinion no added value” on such questions.
Technocracy poses a further difficulty: The limits of human reason assure that experts can be wrong, sometimes egregiously. If the history of scientific materialism in politics shows anything, it is that scientific experts can be as fallible as anyone else. They are capable of being blinded by their own prejudices and going beyond the evidence in order to promote the policies they favor. Alfred Kinsey’s empirical claims about the sexual behavior of the general American public were junk science, given his deeply flawed sample population; yet that did not stop him from boldly making his claims and vigorously defending them as sound science.
The errors of the scientific community in the early 20th century were profound. For decades, eugenics—the effort to breed better human beings by applying the principles of Darwinian biology to reproduction—was embraced as legitimate by America’s leading scientists and scientific organizations such as the AAAS. Critics of eugenics, meanwhile, were roundly stigmatized as anti-science and religious zealots. Yet the critics of eugenics were the ones who turned out to be right, not the scientific elites.
Similarly, the lobotomy was uncritically embraced for years by the medical community as a miracle cure, and the scientist who pioneered the operation in human beings won a Nobel Prize for his efforts. Only after tens of thousands of individuals had been lobotomized did healthy skepticism prevail.
The point is that public policy claims made by scientists ought to be scrutinized by policymakers and citizens in the same way that public policy claims made by other interested parties are scrutinized. Any suggestion that policymakers should simply rubber-stamp the advice of the current majority of scientists is profoundly subversive of the fundamental principles of representative democracy. As equal citizens before the law, scientists have every right to inform policymakers of the scientific implications of their actions, but they have no special right to demand that policymakers listen to them alone.
Unfortunately, there seems to be a growing chorus urging that public policy be dictated by the majority of scientific experts without input from anyone else. Today, this bold assertion is made not just with regard to evolution, but concerning a host of other controversial issues such as sex education, euthanasia, embryonic stem-cell research, cloning, and global warming. On these matters, any dissent from the orthodoxy of the “experts” allegedly represents a “war on science.”
A second influence of scientific materialism on public policy has been the cultivation of a vigorous form of utopianism. Believing they possessed the key to understanding and ultimately controlling human behavior, defenders of scientific materialism over the past century were supremely confident that science could usher in heaven on earth if experts were only permitted to implement its teachings without obstruction.
Their heady optimism is not difficult to understand. By the late 19th century, science had produced marvelous advances in medicine, agriculture, sanitation, and transportation. Why could the triumphs of the scientific method over the natural world not be extended to the social sphere? If science could prevent the spread of physical diseases like smallpox, why could it not also prevent outbreaks of social diseases like crime and poverty? If science could breed better strains of cattle and corn, why could it not breed better kinds of people?
Addressing the American Breeders Association in 1913, U.S. Secretary of Agriculture James Wilson acknowledged that the wholesale replacement of “inferior” human stocks with “the best part of the human race…at first seems like an Utopian vision” but then quickly added: “Why should it not come? Must science stop in its beneficence with the plant and the animal? Is not man, after all, the architect of his own racial destiny?”
Wilson’s rosy rhetoric revealed the startling naivet at the heart of the scientific materialist agenda. Scientists and policymakers who were readily skeptical of claims made by religion or tradition turned out to be supremely credulous when it came to claims made in the name of science. They accepted at face value the purported benefits of such procedures as lobotomies, psychosurgery, and forced sterilization. They made grand promises about how science could solve intractable social problems such as crime and poverty. They showed little appreciation for the fact that science, like all human endeavors, could be misused, especially when allied with political power.
Eugenist Herbert Walter sanguinely predicted that nothing like “the Spanish Inquisition or…the Salem witchcraft persecution” would take place in an age of modern science. Only two decades before the Nazis ascended to power in Germany, Walter predicted that “it is unlikely that the world will ever see another great religious inquisition, or that in applying to man the newly found laws of heredity there will ever be undertaken an equally deplorable eugenic inquisition.” Eugenist Harry Laughlin similarly asserted with confidence that no one—not even one person—had been wrongly sterilized in America.
AAAS president Charles Eliot at least acknowledged the prospect that physical and chemical science could be enlisted “as means of destruction and death.” But even he thought the application of biology to society posed no danger: “Biological science has great advantage in this respect over physical and chemical [science]. It can not so frequently or easily be applied to evil ends.” Eliot wrote those words in 1915 as the eugenics movement was well on its way to forcing the sterilization of thousands of people across America.
This is not intended to imply that scientific materialism was the only source of utopianism in America. There were elements of utopianism in religious reform movements of the 1800s and early 1900s, as well as in various expressions of secular populism. But scientific materialism was one of the most powerful sources of utopianism because it eroded previous obstacles to the spread of utopianism.
Prior to the rise of scientific materialism, a strong realist, anti-utopian sentiment in American political culture counterbalanced the idealism and utopianism of reformers. America’s Founders, in addition to their idealism, displayed a keen realism about the imperfections of human nature. “If men were angels, no government would be necessary,” James Madison wrote in The Federalist. “The best Institutions may be abused by human depravity…. [T]hey may even…be made subservient to the vilest of purposes,” echoed George Washington.
The anti-utopian undercurrent in American culture continued during the 19th century when writers such as Nathaniel Hawthorne satirized the overblown hopes of contemporary reformers. In his short story “Earth’s Holocaust” (1844), Hawthorne described how militant do-gooders planned to cleanse the earth of imperfection by creating a giant bonfire out on the western prairies on which they could throw every conceivable cause of social evil. The great conflagration burned for days and consumed everything thrown into it, but the fire still did not produce the perfect society. Hawthorne’s punch line was that the reformers failed because they could not reach the ultimate cause of human misery: the human heart. Social conditions might wax and wane, but sinful human nature was unchangeable this side of heaven.
Scientific materialism tried to refute this kind of political realism. According to its adherents, human nature was not fixed; it could be remade through the methods of modern science. Men may not be angels now, but under the right biological and environmental conditioning, they might become angelic. Scientific breeding and medical treatment could usher in a new age only dreamt of by previous reformers. Scientific materialism undermined the very premises of American political realism.
One would like to believe that Americans have learned from the excesses of scientific utopianism, but current political controversies inspire no confidence in this regard. The miracle cures may be different today, but the utopian rhetoric is remarkably similar.
Seventy years ago, eugenics promised to cure America’s social problems through better breeding. Today, mental-health crusaders promise to eliminate behavioral problems among America’s children by screening every schoolchild for mental illness and putting millions of them on psychoactive drugs. Like the eugenics crusade of the last century, the current push to increase dramatically the number of children on psychoactive drugs reduces behavioral problems to a purely material cause. Like the eugenics crusade, it is accompanied by grandiose claims that go far beyond the actual science. Like the eugenics crusade, it is justified in humanitarian terms even while it raises serious issues about civil liberties and human dignity. How many people will be harmed before this latest crusade runs out of steam?
A third influence of scientific materialism on public policy has been dehumanization. Although its supporters saw scientific materialism as a way to solve social problems and advance human dignity, the historical record shows that it often denigrated entire classes of humanity. The claim that men and women could be reduced to their physical capacities plus their material inputs turned out to be profoundly dehumanizing.
In criminal justice, the belief that a person was, in the words of one textbook, “no more ‘responsible’ for becoming wilful and committing a crime than the flower for becoming red and fragrant” may have led to more humane treatment in some cases, but it also robbed the criminal offender of the dignity of being treated as a rational being whose choices matter. At the same time, in many other cases it opened the door to horrific forms of “scientific” rehabilitation that never would have been allowed if they had been imposed as punishments.
- In sex education, the depiction of human sexuality as little more than mammalian behavior reduced human beings to the level of animals and drained human relationships of the moral and spiritual context that gave them their deepest meaning.
- In the corporate world, scientific materialism fed eugenic employment policies and the use of advertising to manipulate consumers scientifically into purchasing products.
- In the welfare system, the quest to identify the biological roots of poverty paved the way for forced sterilization, anti-immigrant hysteria, and the demonization of anyone who was regarded as physically or mentally imperfect.
The impact of scientific materialism on welfare policy is especially worth noting because it directly challenged the guiding principles of the existing social-welfare system. Charity in the traditional view was premised on the idea that all human beings are created in the image of God and therefore worthy of assistance, mercy, and redemption. Eugenic welfare reformers denounced such humanitarian views as false and dangerous. Harvard biologist Edward East attacked the idea that “man is created in the image of God” as unscientific and suggested that the claim that all human beings have equal worth is ludicrous. Margaret Sanger warned of the “dangers inherent in the very idea of humanitarianism and altruism, dangers which have today produced their full harvest of human waste, of inequality and inefficiency.”
America’s experience with the dehumanizing effects of scientific materialism was far from exceptional. The three regimes of the 20th century best known for being founded explicitly on the principles of scientific materialism—Soviet Russia, Nazi Germany, and Communist China—are most remembered for their horrific brutality rather than any advancement of human dignity. In Germany, the connection between scientific materialism and Nazi crimes against humanity is unmistakable, as historian Richard Weikart has ably demonstrated in his recent book on the influence of Darwinian ethics in Germany.
The dehumanizing effects of scientific materialism remain a live issue for public policy today, especially in so-called right-to-die cases. Efforts to redefine mentally and physically disabled infants and adults as already dead, the widespread careless diagnosis of the “persistent vegetative state,” and the demeaning rhetoric of bioethicists such as Peter Singer all raise, chillingly, the ghosts of evils past.
A fourth influence of scientific materialism on public policy has been relativism. Darwinian theory in particular has supplied a powerful justification for evolving standards in politics and morality. Part of the justification is by way of analogy: If evolution is the normal state of the natural world, why should it not be regarded as the normal state of politics?
The preeminent achievement of applying the evolutionary paradigm to politics was the doctrine of the evolving Constitution championed by Woodrow Wilson and other Progressives. No longer would American government be hamstrung by a static understanding of human nature or human rights. It must adapt and evolve to meet the challenges of new conditions. In the words of Wilson:
[L]iving political constitutions must be Darwinian in structure and in practice. Society is a living organism and must obey the laws of Life…. [A]ll that progressives ask or desire is permission…to interpret the Constitution according to the Darwinian principle.
But the link between Darwinian theory and relativism is not merely analogical. In The Descent of Man, Darwin depicted morality as the evolving product of natural selection. Rather than reflecting timeless standards of truth sanctioned by God or nature, moral codes evolved by natural selection to promote survival. As the conditions for survival changed, so did what was moral for any species. In one situation, maternal love might be moral; in another situation, infanticide. In one situation, kindness might be moral; in another situation, cruelty.
While Darwin surely hoped that traditional virtues were biologically beneficial in 19th century Britain, if circumstances changed and those virtues no longer promoted survival, he would have to grant that they would no longer be virtues. Darwin himself admitted as much in a particularly startling passage:
If…men were reared under precisely the same conditions as hive-bees, there can hardly be a doubt that our unmarried females would, like the worker-bees, think it a sacred duty to kill their brothers, and mothers would strive to kill their fertile daughters; and no one would think of interfering.
Whatever his own personal moral preferences, Darwin’s reductionistic account of the development of morality left little room for objectively preferring one society’s morality over another’s. Each society’s moral code presumably developed to promote the survival of that society, and so each society’s moral code could be considered equally “natural.”
Darwin’s evolutionary explanation of the origin of the family was just as relativistic. It was clear from his account that there was no right form of marriage or family life for every time and place. Sexual standards differed sharply across societies and human history, and each form of family life was adapted to meet the biological and environmental requirements of its particular situation. In Darwin’s framework, everything that regularly occurred in nature must be regarded as normal almost by definition.
While for the most part Darwin did not press his relativistic analysis of morality to its logical conclusion, he laid the groundwork for others who came after him. The ultimate result of Darwinian moral relativism can be seen in the sex research of zoologist Alfred Kinsey and the moral pluralism embraced by sex education reformers from the 1960s to today. Their efforts to convince the public that all variations of sexual behavior are “normal”—including, according to some of them, adult-child sex and even incest—were a logical culmination of the approach Darwin pursued in The Descent of Man.
Stifling Free Speech
A final influence of scientific materialism on public policy has been the suppressing of free speech and debate over the public policy implications of science. This is surely one of the most striking ironies of the effort to enlist scientific materialism to reform society.
In their own minds, proponents of scientific materialism were the defenders of enlightenment against superstition and rational debate against unreasoning dogmatism, but the rhetoric they employed against their opponents is often far from conducive to open debate. The repeated insistence that scientists know best and, thus, politicians and the public should blindly accept the policy views of scientists did not encourage critical scrutiny of scientific claims made in politics.
Even less conducive to genuine debate was the frequent playing of the religion card in policy disputes involving science. With the help of sympathetic journalists, proponents of scientific materialism portrayed every policy dispute as a battle pitting the enlightened forces of science against bigoted religious extremists. Promoters of eugenics heaped scorn on Catholic and fundamentalist critics of forced sterilization. Advocates of Kinsey-style sex education demonized parents who raised objections as Bible-thumpers who were conspiring against democracy. Today, defenders of a Darwin-only biology curriculum similarly accuse their opponents of trying to insert the Biblical creation story into science classes, even when such claims are inaccurate.
Perhaps the most disturbing aspect of these attempts to frame policy disputes in terms of religion versus science is the attempt to shift the focus from the content of the debates to the supposed motives of those who oppose any claim made in the name of science. Instead of addressing the policy arguments raised by critics of sex education or Darwin-only science education, defenders of scientific materialism try to make the religious beliefs of their opponents the central issue, arguing that critics’ real or perceived religious motivations somehow disqualify them from being active participants in the public square.
America is a deeply religious country, and no doubt many critics of the agenda of scientific materialism are motivated in part by their religious beliefs. So what? Many opponents of slavery were motivated by their religious beliefs, and many leaders of the civil rights movement were even members of the clergy. All of them had an equal right with other citizens to raise their voices in public debates. So long as religious persons in politics offer secular justifications for their policy proposals, they have every right to demand that their ideas be heard on the merits regardless of their private religious views.
In the controversy over the teaching of Darwinian theory in public education, reporters often note the supposed religious beliefs of critics of Darwin’s theory, but they almost never investigate the anti-religious beliefs of many of the leading defenders of evolutionary theory. Why? Motives are either relevant for both sides of a political dispute, or they are irrelevant to either side. The willingness of some reporters to embrace uncritically the agenda of Darwinists represents a grave disservice to the public as well as a serious breach of journalistic ethics. Given the troubled legacy of scientific materialism in public policy, what is needed is greater critical scrutiny of scientific materialism in politics, not less.
Conservatives who are uncomfortable with current debates over science and public policy need to realize that the debates are not going to go away, because scientific materialism raises fundamental challenges to the traditional Western understanding of human nature and the universe. Scientific materialism is central to arguments over moral relativism, personal responsibility, limited government, and scientific utopianism.
Moreover, these debates are not going away because many of America’s most influential scientists are avowed materialists, and it is nearly impossible for them to separate their materialism from their policy recommendations. Nearly 95 percent of biologists in the National Academy of Sciences, for example, identify themselves as either atheists or agnostics. We are not supposed to wonder how their materialism influences their application of scientific expertise to public affairs?
As members of a free society, we should be willing to defend vigorously the right of laypeople and scientists to voice dissent from the current scientific consensus, whether the issue is global warming, the over-prescription of Ritalin for children, the content of sex education, or even the debate over Darwinism and intelligent design.
We do not always have to agree with dissenters in order to defend their right to present their views free from harassment and intimidation. But if we are unwilling to defend their right to debate scientific issues implicating public policy, we have no grounds for complaint when the agenda of the scientific elites leads to coercive utopianism or when every attempt to raise a different point of view is smeared as an attack on science.
Contrary to the assertions of some, robust public scrutiny of claims made in the name of science does not constitute a “war against science.” Indeed, it may be the very thing that saves science from its own excesses.
- Hugh Elliot, Modern Science and Materialism, 2nd impression (London: Longmans, Green, and Co., 1927), p. 138.
- C. S. Lewis, The Abolition of Man (New York: Macmillan Publishing, 1947), p. 84.
- Richard Dawkins, The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design (New York: W. W. Norton and Co., 1996), p. 6.
- J. McKeen Cattell, “Homo Scientificus Americanus,” Science, April 10, 1903, p. 569.
- Charles W. Eliot, “The Fruits, Prospects and Lessons of Recent Biological Science,” Science, December 31, 1915, p. 926.
- “Eugenics in Politics,” The New York Times, October 9, 1921, p. 93.
- C. S. Lewis, “Is Progress Possible? Willing Slaves of the Welfare State,” in God in the Dock: Essays on Theology and Ethics (Grand Rapids: Eerdmans, 1970), p. 315.
- See, for example, Chris Mooney, The Republican War on Science (New York: Basic Books, 2005).
- James Wilson, “Presidential Address,” American Breeders Magazine Vol. 4, No.1 (First Quarter, 1913), p. 56.
- Herbert Walter, “Human Conservation,” in Horatio Hackett Newman, Evolution, Genetics and Eugenics, 3rd ed. (Chicago: University of Chicago Press, 1932), p. 531. The essay was reprinted from a book published by Walter in 1913.
- Harry Hamilton Laughlin et al., Legal Status of Eugenical Sterilization (Chicago: Fred J. Ringley Co., 1930), p. 79.
- Eliot, “The Fruits, Prospects and Lessons of Recent Biological Science,” p. 928.
- James Madison, Federalist Paper No. 51 in Alexander Hamilton, James Madison, and John Jay, The Federalist Papers (New York: New American Library, 1961), p. 322.
- George Washington, “[Proposed Address to Congress],” in John C. Fitzpatrick, ed., The Writings of George Washington from the Original Manuscript Sources, 1745-1799 (Washington, D.C.: United States George Washington Bicentennial Commission), Vol. 30, pp. 301-302.
- Nathaniel Hawthorne, “Earth’s Holocaust,” at www.eldritchpress.org/nh/holo.html (July 26, 2005).
- Nathaniel Cantor, Crime, Criminals and Criminal Justice (New York: Henry Holt and Co., 1932), p. 265.
- Edward M. East, Heredity and Human Affairs (New York: Charles Scribner’s Sons, 1927), p. 29.
- Margaret Sanger in Michael W. Perry, ed., The Pivot of Civilization in Historical Perspective (Seattle, Wash.: Inkling Books, 2001), p. 214.
- Richard Weikart, From Darwin to Hitler: Evolutionary Ethics, Eugenics, and Racism in Germany (New York: Palgrave Macmillan, 2004).
- Woodrow Wilson, The New Freedom: A Call for the Emancipation of the Generous Energies of a People, with an introduction and notes by William Leuchtenburg (Englewood Cliffs, N.J.: Prentice-Hall, Inc., 1961), pp. 41-42.
- Charles Darwin, The Descent of Man, and Selection in Relation to Sex (Princeton, N.J.: Princeton University Press, 1981), Vol. 1, p. 73. This is a reprint of the first edition, which was published in 1871.