Evolution, Theory of

Evolution, Theory of. Until the late 1850s, when the British philosopher Herbert Spencer introduced the term “evolution” to describe the history of the universe as a progression from the simple to the complex, writers discussing what came to be called evolution typically labeled it the “development” theory or, when referring to the organic world, the “transmutation” hypothesis. Few Americans paid any attention to such speculations until after 1844, when Robert Chambers, a Scot, anonymously published Vestiges of the Natural History of Creation, a synthesis of organic and inorganic development theories that elicited more ridicule than respect in the United States. Intense discussion of organic evolution did not begin until the appearance of the British naturalist Charles Darwin's Origin of Species in 1859. Although Darwin himself rarely used the term “evolution” to describe his views, they came to typify what others meant by evolution. Indeed, by the 1870s American commentators were commonly using “evolution” and “Darwinism” interchangeably.

Darwin's primary goal in writing the Origin of Species was to overthrow “the dogma of separate creations,” which he regarded as “utterly useless” as a scientific explanation. By the mid‐1870s the overwhelming majority of Darwin's fellow naturalists in America—botanists, zoologists, geologists, and anthropologists—had come to agree with him. Some were already calling evolution an “ascertained fact,” though virtually none assigned as much importance as Darwin did to natural selection as the primary agent of organic change. Even Darwin's leading American champion, the Harvard botanist Asa Gray, broke with his English friend in attributing the appearance of human beings and complex organs (such as the eye) to special divine intervention. Until the second third of the twentieth century, few American biologists identified natural selection as the mechanism of evolution.

During the early scientific debates over evolutionary theory and the efficacy of natural selection, religious leaders typically sat on the sidelines, many of them doubting that evolution would ever be accepted as serious science. By the mid‐1870s, however, American naturalists were becoming evolutionists in such large numbers that the clergy could scarcely continue to ignore the issue. Some liberals simply baptized evolution as God's method of creation. But most religious leaders—whether Protestant, Catholic, or Jewish—rejected evolution, especially as it applied to human beings, or remained silent on the subject. Darwinism seemed not only to deny design in nature but, more important, to undermine the historical and ethical teachings of the Bible. Americans who believed that God had created human beings in his image took umbrage at Darwin's assertion in The Descent of Man (1871) that “Man is descended from a hairy quadruped, furnished with a tail and pointed ears.”

Despite widespread criticism of evolution in the late nineteenth and early twentieth centuries, no group mounted an organized crusade against it until after World War I. Concerned by the increasing exposure of the nation's youth to evolution in high schools and emboldened by erroneous rumors that Darwinism (that is, evolution) lay on its “death‐bed,” Protestant fundamentalists in the 1920s sought to outlaw the teaching of human evolution in the public schools of America, which they accomplished in Tennessee, Mississippi, and Arkansas. In a celebrated 1925 trial, a court in Dayton, Tennessee, found John Thomas Scopes, a high‐school science teacher, guilty of violating the state's antievolution law. Although the state supreme court later overturned Scopes's conviction, the groundswell of public opposition to evolution convinced many science teachers and most textbook publishers to soft‐pedal discussions of evolution.

After seven decades of debating possible mechanisms of evolution—the inheritance of characters acquired by use and disuse, the influence of climatic changes and environmental catastrophes, the role of dramatic mutations and elusive internal forces—American biologists in the 1930s and 1940s finally reached a consensus about the central role played by natural selection operating on minute variations. Together various geneticists, systematists, paleontologists, embryologists, and botanists forged what came to be called the modern or evolutionary synthesis. Above all, as William B. Provine has pointed out, the so‐called synthesis squeezed out mechanisms that allowed for purpose and design in evolution.

In the 1960s evolution reappeared in American classrooms with a vengeance, as school districts across the land adopted the federally funded Biological Sciences Curriculum Study textbooks, which featured evolution as “the warp and woof of modern biology.” Outraged conservative Christians launched a counterattack that continued for the rest of the century. For a hundred years following the publication of the Origin of Species, antievolutionists had been united by their antipathy to human evolution, not by agreement on the mode of creation. They typically experienced little difficulty accommodating the evidence of ancient life forms with their reading of Genesis, either by interpreting the “days” of the first chapter of Genesis as geological ages or by assuming a huge chronological gap between the creation “in the beginning” and the much later Edenic creation. Beginning in the 1960s, however, large numbers of them turned their backs on such accommodating schemes in favor of young‐earth, or scientific, creationism, which collapsed virtually the entire geological column into the year of Noah's flood and shrank Earth history to a mere 6,000–10,000 years. In the early 1980s two states, Arkansas and Louisiana, passed legislation mandating the teaching of this “creation science” whenever “evolution science” was taught, but the U. S. Supreme Court in 1987 ruled that such laws violated the First Amendment to the Constitution, requiring the separation of church and state. This ruling prompted antievolutionists in the 1990s to push instead for the teaching of “intelligent design,” based on the complexity of organic structures, and for treating evolution as a mere “theory.”

By 2000 virtually all Americans, creationist and evolutionist alike, accepted the reality of “microevolution” (which for conservative Christians meant change within the originally created “kinds” of plants and animals), but the country remained bitterly divided over “macroevolution.” Public‐opinion polls in the 1990s revealed that 47 percent of Americans, including a quarter of college graduates, believed that “God created man pretty much in his present form at one time within the last 10,000 years.” Another 40 percent thought that “Man has developed over millions of years from less advanced forms of life, but God guided this process, including man's creation.” Only 9 percent supposed that “Man has developed over millions of years from less advanced forms of life” with God having no part in the process.
See also Bill of Rights; Biological Sciences; Bryan, William Jennings; Education: Education in Contemporary America; Fundamentalist Movement; Religion; Science: Revolutionary Era to World War I; Science: From 1914 to 1945; Science: Since 1945; Scopes Trial.

Bibliography

James R. Moore , The Post‐Darwinian Controversies: A Study of the Protestant Struggle to Come to Terms with Darwin in Great Britain and America, 1870–1900, 1979.
Peter J. Bowler , Evolution: The History of an Idea, 1984.
Jon H. Roberts , Darwinism and the Divine in America: Protestant Intellectuals and Organic Evolution, 1859–1900, 1988.
Ronald L. Numbers , The Creationists, 1992.
William B. Provine , Progress in Evolution and Meaning in Life, in Julian Huxley: Biologist and Statesman of Science, ed. C. Kenneth Waters and Albert Van Helden, 1992, pp. 165–80.
Gregg A. Mitman and and Ronald L. Numbers , Evolutionary Theory, in Encyclopedia of the United States in the Twentieth Century, ed. Stanley I. Kutler, 4 vols., 1996, 4: 859–76. 1979.
Ronald L. Numbers , Darwinism Comes to America, 1998.
Ronald L. Numbers and John Stenhouse, eds., Disseminating Darwinism: The Role of Place, Race, Religion, and Gender, 1999.

Ronald L. Numbers