Chapter 19 Chapter 10 The Social Implications of Evolution-1

The phrase "social Darwinism" conjures an image as if human beings are in a desperate struggle for survival, and as if social Darwinists advocate weeding out the unfit as a necessary step to progress.From Richard Hofstadter's book, Social Darwinism in American Thought (Hofstadter, new edition, 1959), we know that this invented illusion often competes with the brutal capitalist got in touch.The best example of this image is the industrial revolution at the end of the 19th century, when those "robber capitalists" competed cruelly by exploiting the people in order to obtain the maximum profit.It seemed inevitable that Darwinian metaphors would be used to uphold the norms of struggle preached by industrialists.If the natural world progresses through individual competition, then the survival of the fittest must be the key to human economic and social progress.Of course, Hofstede's book touches on other situations that make use of the Darwinian analogy.The important arena of struggle may not be between individuals at all, but between nations or races, fighting to preserve imperialism, colonialism, and slavery.There are even societies in which the struggle for existence is replaced by a form of artificial selection called eugenics, due to a slight misinterpretation of the argument for struggle.Its role is to control the reproduction of the population, thereby preventing the reproduction of non-adaptive individuals. ##Given its wide range of connotations, it is not surprising that it is difficult to give a precise definition of "social Darwinism" (Halliday: 1971; Rogers, 1972).A recent study of "social Darwinism" in the UK (Jones, 1980) showed that even liberals and socialists can adapt the idea of ​​natural selection to their own ends.It is impossible to think of Social Darwinism as a simple and obvious application of Darwinism to the human sphere.The link between biology and social thought can be made in different ways, and in each case a certain aspect of scientific theory is selectively emphasized.Those who tout war as an evolutionary drive are convinced that individual competition reduces a people's ability to resist external enemies.In contrast to the dazzling new social tendencies, biological ideas were used as a means of rationalizing established ideological positions.The link between science and ideology also works both ways; scientific theories are to some extent influenced by the social context in which they are formulated.If ruthless capitalism appears to be the direct application of natural selection to economics, we must remember that Darwin's theory itself is often thought to be founded on the influence of Malthus (Chapter 6; Young, 1969, 1971b, 1973). ideological basis. ##Historians must know many ways to analogize society on a biological basis, but if they extend "social Darwinism" to cover so many different ideas that "social Darwinism" becomes essentially When it's meaningless, that's also going to get you nowhere.Darwin's name is often used by those systems of thought concerned with social progress, with the result that Darwin's theory suffers from the public the bad name that other theories rightfully bear.Bannister (1970, 1979) challenged Hofstede's claim that the capitalist form of social Darwinism was prevalent in late-nineteenth-century American thought.His attack is two-way, not only against the degree of so-called popularity, but also against the internal logic of the analogy with Darwin's thought.He points out that liberal historians have deliberately exaggerated an earlier generation's reliance on the meaning of struggle, in order to emphasize how superior their views are to this polished vulgarity. "Social Darwinism" is a term that has been criticized by opponents of free competition.The frequency with which industrialists use the language of Darwinism may be overestimated, since many ideas that appear to advocate the logic of natural competition are actually motivated by quite different motives.This leads to a debate about what real purpose Herbert Spencer's philosophy of individualism has.For Hofstede, it was Spencer who spread Social Darwinism from England to America.However, Spencer's preference for Lamarckism prevented him from accepting the view of natural selection in biology. It can also be considered that he regarded free competition more as the stimulation of people's behavior than the elimination of the unsuitable. ## From the other extreme of political ideas, it is important to understand the relationship between Darwinism and Marxism (Heyer, 1982).Marx welcomed the idea of ​​evolution because of its inherent materialist character, but from the outset he believed that Darwin's mechanisms reflected the competitive climate of Victorian capitalism.It is now clear that the alleged story of Marx dedicating a volume of Capital to Darwin was based on a misinterpretation of their correspondence (Colp, 1974; Feuer, 1975; Fay, 1978).Only a slight resemblance can be found between Darwin's concept of struggle and Marx's belief in the class struggle as the driving force of history, since the latter has its origins in dialectical philosophy.In post-revolutionary Russia, Darwinism has always been hostile, as in the case of Lysenko (see Chapter 9). ## Marxists' rejection of choice theory is understandable, but we should not be led astray into thinking that Darwinism's connection to capitalism is unquestionable.The fact that Spencer was a Lamarckian tells us that there is more than one biological analogy to the model provided by the free enterprise society.The Spencer case also demonstrates that non-Darwinian evolutionary theories may play a considerable role in social disputes.Most Lamarckists opt for a social policy of state intervention as a means of creating better conditions.They hoped that the resulting improvements would have a genetic effect, leading to a real biological advance in the race itself.The eugenics movement also advocated state regulation, but with a very different purpose. The eugenics movement hoped to limit the reproductive ability of the unfit.The extensive contemporary literature on the movement suggests that there was another source of scientific inspiration independent of Darwinism.Although eugenics was created in England under the influence of Darwinian theories, eugenics flourished in the United States after harnessing the new science of Mendelian genetics.But early geneticists rejected natural selection as a mechanism of evolution.They declared that the "bad" genes of the human race had to be artificially selected to weed out, ignoring the assumption that natural evolution was achieved by more rapid replication of adaptive genes. ## The interplay of biological and social thought is complicated by the fact that scientific theories are often embroiled in contemporaneous controversies, with the parties to these controversies differing widely in their fundamental perspectives.Can the above-mentioned political differences be seen in opposing attitudes on the question of which of "nature and nurture" is the most important factor in determining human quality? (Pastore, 1949; Cravens, 1978).Those who believe that nature—that is, heredity—is a fundamental influence reject the notion that improvement and education have beneficial effects on human character.If a man has inherited bad qualities, nothing can help him, and any attempt is a waste of money.This tendency produced conservative political thought based on the need to limit the number and influence of the underclass, since those living in the underclass were believed to be the main source of bad qualities.Weeding out the unfit can be done by natural or artificial selection, by social Darwinism or eugenics.Both Darwinism and Mendelism provided the scientific basis for eugenics because both emphasized the determinative influence of heredity on the biological qualities of an individual.Conversely, the Lamarckian emphasis on "soft inheritance" can be seen as an extreme form of the belief in "man can conquer nature".Lamarckism believes that if there are better external conditions, human nature can be improved 〖HTH〗〖HTSS〗, and that this improvement can be inherited from generation to generation.In fact, for supporters of "acquired determinism", there is no need to advocate genetic effects, and one can also argue that better conditions will create better human nature.Thus, despite the decline of Lamarckism, liberal ideas continued to prevail in the 20th century. ## There is also a thought much deeper than any particular biological theory, which tends to consider human differences in terms of rank.Eugenics and social Darwinism are based on the hierarchy of individuals within a society.The assumption that some people are inherently more capable than others reflects the fact that society is divided into upper and lower classes.The tendency to classify by race is even more prevalent.Europeans almost inevitably believed that other races were inferior to them, and their inferiority was measured by their technological and social development.It is easy to imagine that the "lower" races correspond to the "earlier" stages in the passage from the ape to the highest form of man.In theory, Darwinism should have fundamentally destroyed the concept of linear and hierarchical progress, because Darwinism emphasizes the continuous branching characteristics of evolution.But virtually all evolutionists accept that human origin is a linear schema, and use this view to justify prevailing racial discrimination.Lamarckism should be more readily adopted by those who consider evolution in terms of hierarchy, since Lamarckians are closer to the belief that evolution is likened to the progressive development of an embryo toward an ultimate goal.The biologists who have most persistently attempted to establish racial hierarchies have almost always incorporated a considerable Lamarckian element into their biological thinking.It is easier to deduce a social prejudice into a "scientific" theory through a non-Darwinian approach, although in this case none of the theories completely escapes the widespread underlying attitude.

Social Darwinism The most familiar view of social Darwinism is that which justifies the competitive spirit of Victorian capitalism in terms of the "struggle to live".But the question that some modern historians have been left unresolved is the extent to which the arguments of social Darwinism were used at the time, even with similar differences in the understanding of Darwin's own beliefs.Greene (1977) cites a variety of interpretations, ranging from those who at one extreme condemn Darwinism for promoting aggressive individualism (Harris, 1968) to those who deny Darwin's sympathy for social Darwinism at the other extreme point of view (Freeman, 1974).Certain aspects of Darwin's writings can indeed be interpreted from any angle.Greene points out that Darwin was influenced by, and not unaware of, the Victorian ethos that favored economic competition.Darwin saw the role of individual and tribal competition in human evolution, and feared that loose selection in civilized groups would be harmful to the race.At the same time, he was reluctant to accept some of the more extreme implications of free competition policy.He was amazed when he read a newspaper article declaring that his theory justified Napoleon and every profiteer.Although he felt that something was needed to stop the spread of bad qualities within the race, he clearly did not want to see a competition based on power and cunning.

The paradox in Darwin's own thinking can be resolved simply by linking Darwin to the movement that Jones (1980) sees as "the first meaningful use of Darwin's theory in a political context."This was not an aggressive form of Social Darwinism, but a more traditional form of liberalism; its fundamental aim was to limit the influence of the landed aristocracy.These liberals are not against the existence of a ruling class, but only against the degeneration of existing rulers.They pinned their hopes on a new 〖HTH〗natural〖HTSS〗nobility in the form of a professional class that should allow them to dominate in society.The quarrel between Darwinism and religion can be explained, at least in part, by the new class's use of evolutionary theory as a means of attacking the Church, the traditional hallmark of authority (Turner, 1978; Desmound, 1982).Darwin himself is a manor owner, and he has to deal with the affairs in Dunn's countryside every day.Some, like Aldous Huxley, also took an increasingly important place in public affairs at the national level.Moore (1982) argues that by burying Darwin in Westminster Abbey, Darwin's followers established themselves as a new ruling class, "under new management", resisting the old social hierarchy.The movement did not necessarily produce an aggressive social Darwinism, since the movement itself had confirmed the superiority of the new ruling class.If the number of unfit people at the bottom of society is so large that the whole society is overwhelmed, the solution is not to let them starve, but to limit their reproduction through government control.While Darwin was skeptical of artificial selection of humans, the professional class turned increasingly supportive of the eugenics movement towards the end of the 19th century.

A more extreme form of social Darwinism advocates a radically free competition policy aimed at breaking free from economic competition.The state must loosen restrictions on the freedom of movement of individuals, allowing individuals to rise and fall according to their abilities.Progress can only occur when the fittest are allowed to strive for economic dominance while those who are not suffer the consequences.This is the image of Social Darwinism that Hofstede describes as an integral part of the capitalist ethic.While some factory owners have used Darwinism in a high-profile defense of the free enterprise system, we must note that Bannister disputes this view, arguing that the popularity of the "struggle for existence" tenet is overrated (see also Heyer, 1982) .The debate inevitably centers on the reality of the extreme form of free competitive individualism promoted by Herbert Spencer and his followers.

From Spencer's early works, such as Social Statics (Spencer, 1851), and later works, such as Man and State (Spencer, reprinted 1969; Peel, 1971; Kennedy, 1978), one can Prove his support for free competition.In his view, the development from primitive society onwards, from feudal society to modern capitalism, is a crucial step in the evolution of human beings.Freedom is necessary for progress to be achieved through the accumulation of many individual efforts.Freedom is also a necessary means to bring all individuals into harmony with social development.Spencer insisted that the state only needs to be concerned with external affairs; as for internal affairs, it does not need to control people's lives and activities.There is no need for the state to control health care, education, and relief for the poor, which people today take for granted.For example, if a person wants to be a doctor or a teacher, then he is free to do these things, and as long as he can get people to pay for his services, he is successful.If he is not good at what he does, it only takes a few reckless customers to drive him away.In this case, the best protection the state can do for the public is to protect the losers from the pain caused by their own incompetence.

A similar view was advocated by Spencer's followers, notably the Yale economist William Graham Sumner.Sumner's philosophy can be summed up in three words: "Roots, Greed or Death." He publicly challenged anyone with a better coaching ability to take his place.He has little sympathy for those who fail in their careers: the lazy and incompetent are punished by nature, and any attempt to moderate frustration only opens the way for the spread of weakness.Factory owners also adopted Spencer's views, or at least claimed to base their actions on his philosophy.Andrew Carnegie claimed to be a disciple of Spencer, while railroad magnates James J. Hill and John D. Rockefeller used the term "survival of the fittest" to justify unbridled competition.

Now, some have questioned Hofstede's claim that there is ever a widespread use of the analogy of choice.Even Sumner disagreed with Spencer's optimism that free enterprise could lead to real progress.Although some examples can be cited, it has been suggested that even within the business world there was only limited acceptance of the "survival of the fittest" creed of life (Wyllie, 1959; Bannister, 1970, 1979).Those who have successfully eliminated their opponents may use this argument to justify their ruthlessness, but most ordinary businessmen, aware of their own weaknesses, beg to differ.Outside the business world, distinctly non-Darwinian social evolution enjoys a certain reputation.

Even if we admit that Spencer's philosophy has gained some support, we still have to ask, to what extent is free competition equal to natural selection?In fact, the connection between the two is at best somewhat similar.The fundamental purpose of economic competition is to establish a monopoly, and once this purpose is achieved, all the benefits of natural competition cease to exist.A successful person will dictate to his followers, and thus influence society, but if he does not have more offspring who inherit his qualities, then there is no corresponding biological effect.Inherited wealth clearly does not equate to inherited ability, although wealth translates into political influence in many cases.In fact, A. R. Wallace adopted this view in his defense of socialism (Durant, 1979).He proposed that if there were no distinction between rich and poor, husbands and wives would choose each other according to their biological qualities, as nature intended.

Seeing Spencer's social philosophy less as a form of natural selection than as an expression of the Victorian commitment to "self-reliance," in Samuel Smiles (1959), You can also find a lot of children with this view.This view later became the naturalization of the Protestant work ethic, and Moore (1985a) pointed out that many Protestant liberals saw Spencer's philosophy as an extension of their traditional moral outlook.The most important purpose of free competition is not to eliminate the unfit, but to encourage everyone to improve themselves through their own efforts.Laziness is considered a greater obstacle to progress than stupidity, and the strategy for idlers is not to destroy them but to compel them to make more effort.The best way of attaining this end is to check all attempts to alleviate the pain of nature's punishment for failure.Spencer, who acknowledged that one of the results of free competition is that the strong "knock over the side" of the weak, no doubt believed when he wrote Man and State in 1884 that spreading socialism was By bad character breeds everywhere in the society.If it were not for the support of the state, it would never be possible for the unfit to multiply to the point of becoming a burden.In Spencer's philosophy, however, true progress arises from the stimulation of individual agency by the fear of failure and poverty.Socialism not only allows the survival of the unfit, but it also destroys the autonomous quality that is so important to social development.The fear of pain teaches everyone how to adjust to the new economic situation, and the next generation learns this directly from their parents.This policy looks less like Social Darwinism and more like Social Lamarckism, which also shows Spencer's biological preference for Lamarckism.It can be seen that what is given to social Darwinism should in fact belong to Spencerism, and there is no similarity to natural selection.

By the end of the 19th century, Spencer's popularity had begun to wane.He attacked the wave of nationalism that was prevailing in many countries as an inefficient form of militarism; however, nationalism turned out to be more powerful than free competitive individualism.The thrill of pride felt by many who had hoped for conquest and colonial expansion suggests that there is a second level of competition, which may also be called Social Darwinism. The credo of "survival of the fittest" was inevitably applied to the expectations of the struggle of nations, each convinced that it had proven itself to be the most adapted.Expectations of future warfare lead to a desire for national unity that runs counter to the corporate freedoms that have been valued in the past.Therefore, although the high-profile Darwinism is sung, the concept of national struggle has begun to deviate from the fundamental feature of the biological selection mechanism-individual competition.

In his book Physics and Politics (Bagehot, 1872), Walter Bagehot emphasized the importance of national cohesion.In deliberately applying the fundamental principle of natural selection to society, Bagehot pointed out that throughout history the strongest nations have dominated their weaker neighbours, and that, insofar as strong nations have contributed to the development of civilization, They are also indeed the fittest.The subordinate peoples are oppressed, if not destroyed, and know the advantages of the conqueror.Bagehot clearly departed from the true spirit of choice theory, for he insisted that the growing power of the state was the main driving force behind the situation.Rather than advocating individual competition, Bagehot admired anything, including religion, that facilitated the subordination of the individual to the will of society.The church and the state should be united for the strength of the nation, while freedom of thought should be suppressed.Throughout history, those peoples who were the first to reach a higher level of organization became the conquerors; this means that the same factors must have governed the competition of nations. In the 20th century, it was still popular for a time to see national or racial competition as central to human progress.The basis of the idea that made the eugenics movement (see below) attractive was that white races must be prevented from biologically degenerating themselves if they were to maintain their superiority over other races.At this time some archaeological anthropologists tried to propose that the fossil record of human evolution showed that advanced humans had been killing inferior humans (Bowler, 1986).The disappearance of Neanderthals from Europe is seen as the same process by which whites wiped out the Aboriginal peoples of the Americas and Australia, only at an earlier time.Until 1949, Arthur Keith established a theory of human evolution. According to this theory, the struggle between tribes and races is the main driving force of evolution.It makes sense that Keith and other advocates of the race struggle were not interested in explaining the emergence of higher races through natural selection.Selection is merely a passive process whose effect is to weed out those races which are left behind in their progress.The concept of struggle already has a meaning of its own, and its function has nothing to do with the biological Darwinian theory. Darwinism has also had some, sometimes contradictory, influence outside the English-speaking world.In France, biological Darwinism had little influence, while social Darwinism there placed little emphasis on the concept of individual struggle (Clark, 1984).In Germany, thinkers from different ideological backgrounds accepted the theory of evolution and were willing to call themselves Darwinists (Kelly, 1982).Historians have paid great attention to the militaristic form of Social Darwinism, according to which war was celebrated as a means by which powerful nations exercised their authority (Zmarzlik, 1972).Advocating the idea of ​​the rule of the fittest is not just a perversion of Darwinism by aristocratic legions.Instead, this view was encouraged by Ernst Haeckel, one of Germany's leading Darwinists (Gasman, 1971).Haeckel made evolution the cornerstone of his quasi-religious philosophy—monism, whose fundamental thesis is the unity of mind and matter (Holt, 1971).An organization called the "Union of Monists" spread monism throughout Germany.Although Haeckel was dismayed that Germany was united by the military rather than the middle classes, he and his followers were quick to endorse a strong central government.The theory of evolution taught them that progress throughout history has been achieved by domination of neighbors by superior races.The struggle must continue to ensure continuous progress, and in the next stage Germany will emerge as world ruler.During World War I, Haeckel was a fanatical nationalist, deeply disappointed by Germany's final defeat. The "Unitarian League" played a role in the subsequent emergence of Nazi ideology, emphasizing the inherent superiority of the Germans and advocating their ultimate victory. Haeckel insisted that for a nation to be strong, it must be unified and centralized.This was the exact opposite of the tone of individualism advocated by Spencer, whose ideas were ridiculed in Germany as a reflection of poor British commercialism.A strong nation cannot tolerate such internal strife that divides the country, but should unite all people to follow the goals directed by the ruler.Curiously, Haeckel, like Spencer, was a Lamarckian in his views on the problems of the internal development of species and societies.But Spencer favored the transition from militarism to capitalism, while Haeckel insisted that national competition remained the more important force driving progress.Therefore, the state must improve the quality of all citizens and cast them into a group running towards a clear goal.Spencer believed that nature must be left to its own devices, because humans could not control the direction of progress; Haeckel believed that humans could master their own agency and build powerful new nations in their own vision of the future. Apart from the pure concept of progress through struggle, there was little in German ideology that resembled the mechanics of choice.It cannot be denied that Darwin recognized the role played by the conquest of states in the process of human progress.From the perspective of biological origin, Nazism and Spencerism are two different combinations of Darwinism and Lamarckism.The Nazis absorbed other aspects of German thought, including racial sentiments such as 〖HTH〗nationality〖HTSS〗better than those around them, a misinterpretation of Nietzsche's concept of the "Superman", and Hegel's idealism national philosophy.The belief that citizens are subservient to the state, and that the aspirations of great leaders represent national goals, is clearly a characteristic of idealism, not Darwinism. eugenics Advocating the idea that the state has a responsibility to control the reproduction of unsuitable citizens is the basis of the eugenics movement.Darwin himself pointed out the problems posed by the lenient nature of natural selection in civilized societies, where strict weeding out of the unfit cannot be carried out.The weakness of social Darwinism, which advocates free competition, is that the least fit in society seldom disappear entirely; indeed, the ghettos of the metropolis were increasingly recognized as breeding grounds for bad characters.It is natural to suppose that the poorest classes of society contain the greatest number of persons of inferior character, since poverty may be regarded as a direct result of human incapacity.Darwin's nephew, Francis Galton, was the first to argue that the problem was growing out of control and that the state must play an active role in controlling the relative proportions of the fittest and the unfit.The mass reproduction of inferior people living in slums will degenerate the entire race, and at the same time cause the loss of public resources.In contrast, professionals with the highest levels of competence tend to have fewer children.The only solution is to reverse this natural tendency through government intervention.In Galton's view, the motivation to use artificial selection as a means to improve racial characteristics seemed religious in its effect.His writings later laid the foundation for the entire eugenics movement. (For a comprehensive review of eugenics, see Blacker, 1952; Allen, 1975b, 1976; Bajema, 1977; Farrall, 1979, Kevles, 1985). It was not until 1883 that Galton invented the term "eugenics", but long before that, he had already begun to try to establish a basic genetic view-abilities are inherited, not produced by education of.In his book "Inheritance of Genius" published in 1869, he obtained evidence through research on many famous families that sons can inherit their father's abilities.From this, he claimed, it was learned that the biological level of the race was maintained by ensuring that people of high ability had more children.Later, this view was called "positive eugenics", that is, the purpose of positive eugenics can be achieved by reducing taxes for professional-class people who have children.At the same time, Galton outlines one of the most influential aspects of that movement: "negative eugenics"; the aim of which was to limit the number of children born to parents who were below average in ability.For the worst members of the poor classes, those who are supposed to be mentally retarded, their diseases should not be treated.Therefore, in Galton's mind, the basic program of eugenics has basically been formed (Forrest, 1974; Buss, 1976; Cowan, 1977; Fancher, 1983). Galton's proposal did not elicit a positive response at first.Many people were shocked by his idea of ​​artificial birth control.There was also great skepticism about Galton's idea of ​​heredity.Furthermore, since children from well-born families are usually better educated than ordinary people, how can we be sure that their abilities are innate?Later, Galton expended much effort to propose a biological statistical technique in direct response to the initial skepticism (Cowan, 1972b).He showed in more detail that heredity controls the nature of populations.He applied statistical methods to the study of variation, which also laid the foundation for the research path of the biostatistics school. Later, his student Karl Pearson used biostatistics to defend Darwinism.It can be argued that the real structure of Pearson's quantitative techniques reflects his desire to provide clear scientific evidence for eugenic policies (Mack enzie, 1982).The same view was found in Pearson's student R. A. Fisher (Bennett, 1983; Norton, 1983). At the turn of the 19th and 20th centuries, Galton and Pearson finally saw their movement begin to gain momentum in Britain (Mackenzie, 1976, 1982; Searle, 1976, 1979; Jones, 1986).Pearson points to the fact that many of the recruits recruited to the British Army during the Boer War came from poor working classes as evidence of racial degradation.Galton founded the Eugenics National Laboratory in 1904, founded the Eugenics Educational Association shortly thereafter, and published the journal Eugenics Reviews.In the first decades of the new century, eugenics emerged as an influential, if not particularly powerful, political faction.At the same time, there are corresponding developments in other places.Birth restrictions on the unfit had been widespread in Germany long before the Nazis came to power (Weiss, 1986).In the United States, eugenics also flourished throughout the early 20th century (M. Haller, 1963; Dickens, 1968; Ludmerer, 1972).The American Fertility Association, a Mendelian group, established the Commission on Eugenics in 1906 and later the Bureau of Eugenics Statistics in 1910 (Allen, 1986). In 1912 the first international eugenics conference was held.What united the eugenics movement in different countries was the belief that genetic manipulation provided a means of scientifically managing the human race.It is for this reason that eugenics—though generally associated with political power—occasionally finds support from left-wing thinkers (Paul, 1984). The purpose of all this activity is primarily to lobby governments that they should pass legislation to improve—or at least maintain—the biological level of the race.A few encouraged the working class to have more children, but the eugenics movement gradually began to focus on limiting the birth rate among members of the lower classes.The amelioration of the race advocated by Galton was replaced by a more pessimistic tendency, based only on preventing the further degradation of the race.The lunatic and the mentally handicapped became the most common targets, and criminal tendencies were seen as a by-product of mental deficiency.In order to provide the necessary and "accurate" means of screening, scientists engaged in psychological testing were encouraged and made the first attempt to establish a scale for measuring intelligence.This method compares mental age with chronological age, which results in an intelligence quotient, or IQ.有人认为，很容易识别出天赋的智力，不过早期的测试并没有能够完全消除教育的影响，因此突出了底层阶级具有明显较差的智力（Gould，1981；Evans and Waites，1981）。优生学运动坚持应该对那些智商水平最低的人加以管制，或者让他们与异性隔离，甚至采取绝育措施，防止他们的生育。美国的一些州还通过了立法，要求智力上低于某个标准的人不能生育。人们还恐惧那些从东欧移居来的“次等”种族群众的繁衍。 20世纪30年代，在纳粹德国，开始了最大规模的绝育工程，并成为纯化“亚利安人种”努力的一部分（Harmsen，1955）。 20世纪早期，一些社会和科学的因素促进了优生学声誉的突然提高。社会工作者们渐渐地转而相信虚伪和无能可以遗传很多代这种遗传观点。有人认为，这些现象表现出来的是生物学的原因，而不是社会原因。那些负责管制疯子和弱智者的人也相信这种品质是通过遗传因素传递的。中产阶级和职业阶级对心智低于平常水平的人在数目上的急剧增长，越来越感到忧虑。中产阶级和职业阶级确信，他们在社会上获得的地位完全是依靠天赋的能力，而且他们还希望能把这种能力传给他们的孩子。他们不想让自己的经济收入被大量用来作为帮助人口不断增长的无能者和疯子的税收；他们的家庭变得越来越小这件事本身也说明了正优生的普遍性正在下降。 从科学的角度看，优生学得益于孟德尔遗传学在1900年以后的迅速发展。高尔顿最初曾经形成自己的观点，来代替在人类中的自然选择，同时，他的英国追随者，特别是卡尔·皮尔孙，也跟着提出了相似的看法。生物统计学上的定量技术不仅被用来证实自然选择的力量，而且还作为研究人类特征遗传的手段，用来证实优生政策的必要性。无论如何，达尔文主义不是遗传唯一的来源；事实上，高尔顿本人并不相信对有差异个体的选择是自然进化的动因。孟德尔定律的重新发现为遗传观点奠定了全新的科学基础。这些规律恰好通过实验说明生物特征能以完整单位的形式进行多代遗传。在美国，并没有以任何形式的高尔顿生物统计学，但是新生的优生学组织却非常热情地支持孟德尔主义。有人认为，一个劣等的特征，比如弱智，是某一个基因在人群中循环的产物。进而，这种观点似乎支持了迅速淘汰劣等特征的建议，或许也支持了防止那些具有此种特征的人生育的建议。虽然大多数早期的遗传学家不相信选择是生物进步的原因，但是他们的理论还是对那种认为有害特征可以传播的不太激进的观点提供了思想基础。