EVOLUTION: BIOLOGICAL, SOCIAL, CULTURAL

The diverse forms of life on earth have emerged probably from a common source, through a process of evolution that has the following characteristics:

1. The course of evolution does not always proceed along a straight path (for example, from simple to complex forms). Instead, it can meander like a stream, directed largely by environmental circumstances, although also affected by limitations on the capacities of organisms to respond to environmental challenges, and by unpredictable "chance" factors. Occasionally it reverses direction in certain respects, as when our own distant monkey-like ancestors became adapted to life in the trees, and our more recent ancestors readapted to living on the ground. When the course of evolution does reverse direction, it generally does so with respect to comparatively few features only, not all features. Thus, we humans retain various characteristics evolved earlier in connection with life in the trees: stereoscopic vision, visual acuity, reduced sense of smell, and hands adapted for grasping.
2. Different groups of organisms sometimes evolve in similar directions in certain respects when exposed to similar environmental conditions. Thus whales—descendants of mammals that lived on land—acquired fishlike shapes when they adapted to life in the water. However, parallelism in evolutionary development generally remains limited: different evolutionary lines do not come close to "merging." Whales, even though living in the ocean and acquiring fishlike shapes, retain basic anatomical and physiological features of mammals, quite different from those of fish.

The life cycle of a human being involves fixed stages (infancy, childhood, adolescence, adulthood, old age) that represent an unfolding of innate potentialities and that culminate in inevitable death. The evolution of a new biological species, by contrast, is a unique historical development involving movement in directions shaped primarily by environmental pressures, without any inevitable "death" or other pre-determined end state.

A "Lamarckian" evolutionary process (named after Jean Baptiste Lamarck, 1744–1829), would involve inheritance of acquired characteristics. Thus, if evolution followed the Lamarckian pattern, giraffes might have acquired their long necks because in each generation necks were stretched (perhaps to obtain food high up in trees, or to detect approaching enemies), and because the effect of each generation's stretching tended to be inherited by the generation that followed. However, Lamarckian ideas were found to be invalid long ago.

A different approach developed by Charles Darwin (1859) and others does not assume that acquired characteristics (such as effects of neck-stretching) are inherited. Rather, it assumes (1) random or randomlike variation among the offspring in each generation (with some giraffes happening by chance to have longer necks than others); (2) natural selection, involving tendencies for certain variants (longer-necked giraffes) to survive and reproduce more than others; and (3) preservation through inheritance of the effects of natural selection (longer-necked giraffes tending to have similarly long-necked offspring, although—as suggested above—there would still be some random variation among these offspring with respect to neck length).

Darwinian ideas challenged traditional Christian religious beliefs by suggesting (1) that we are descended from ape-like creatures and, ultimately, from elementary life forms; (2) that our evolution was basically an unplanned outcome of diverse environmental pressures rather than something planned in advance; and (3) that the earth is old enough for evolutionary processes to have had time to produce the variety and complexity of life forms that we actually find. Although today still resisted by many on religious grounds, Darwinian theory ultimately came to be generally accepted by biologists, with important modifications and certain disagreements about details, and in combination with new knowledge in other areas of biology and other scientific disciplines that was not available to Darwin (see Gould 1982; Stebbins and Ayala 1985; Mayr and Provine 1998).

An inherited trait that has evolved over a long period of time (like the giraffe's long neck) has very likely evolved because it makes some contribution to the survival and reproduction of the organisms possessing it, and because it has consequently emerged and persisted through the Darwinian mechanisms outlined above. However, some traits may appear and persist that are neutral in their implications for survival and reproduction, and even traits that have negative implications may appear and persist if they happen to be linked with traits whose implications are positive.

Bioevolutionary explanations of human social phenomena, sometimes under the label of "sociobiology" (see Wilson 1975), pose a challenge to sociology, as the following example suggests. Stepparents tend to abuse their stepchildren more than biological parents tend to abuse their own children. Sociologists would ordinarily seek to explain this in a way that utilizes sociological and social-psychological concepts only, avoiding assumptions about inherited and biologically evolved traits. A sociobiologist, by contrast, would be more likely to view it as a human manifestation or extension of a biologically evolved tendency prevailing widely among nonhuman mammals: a tendency for individual mammals in stepparent-like positions to kill their "stepchildren," thus increasing their own prospects for producing survivable offspring and perpetuating their own genes (see Beckstrom 1993, pp. 23–29).

An evolutionary explanation of an aspect of human life or society may present that aspect as having emerged (1) as a part of, or a continuation of, biological evolution (as illustrated in the discussion of stepparental child abuse above), or (2) through a process analogous to biological evolution but nevertheless distinct from it, that is, a process of social or cultural evolution. Concepts analogous to those of biological evolution are especially applicable to aspects of culture such as science (Hull 1988) and technology (Basalla 1988) in which the cumulative character of culture is most strongly manifested. Competing scientific hypotheses are the "randomlike variations" in science as an evolutionary process. Research results that evaluate such hypotheses select some of them for survival and others for extinction, and the knowledge that constitutes the outcome of this process in any given generation of scientists is "inherited" by subsequent generations through textbooks, teaching, and research publications. In technological evolution, positive selection (i.e., acceptance) of variations (innovations) depends not only on research results (i.e., on how well they "work") but also on costs, competitive pressures, compatibility with prevailing culture, and other factors.

The evolutionary model is not appropriately applied to social or cultural changes that are cyclical, easily reversed, primarily planned, or repetitive. It may be usefully applied when a complex social or cultural transformation that would be hard to repeat or to reverse occurs gradually without being planned, through environmentally determined selections from among divergent alternative directions of change, and with enough stability to preserve the results of past environmental influence (see Campbell 1965; Richter 1982, pp. 19-34).

Not every process that is called "evolutionary" seems to deserve that label. Some theories pertaining to major transformations of society illustrate this point.

The idea that human society evolves from simple beginnings through comparatively fixed stages came to be commonly accepted in the nineteenth century, although different theorists had different conceptions of what these stages were. Thus we find analyses of transitions from theological to metaphysical to "positivistic" thought-styles (Comte 1875); from savagery to barbarism to civilization (Morgan 1877); from tribalism to slavery, feudalism, capitalism, and then communism (Marx and Engels [1846] 1947); and from simple to compounded, doubly compounded and then triply compounded societies (Spencer [1885–1886] 1967).

When societies, cultures, or civilizations are said to pass from childhood to adulthood, and then to old age, or are said to grow and then decline, we have an analogy not with the evolution of a species but rather with the human life cycle, as illustrated in the works of Oswald Spengler and Arnold J. Toynbee. Nineteenth century "social-evolutionary" theories departed from the life-cycle model in that they did not involve the idea of decline or old age followed by death as the end point of a cycle. Quite the opposite: the trends they described tended to culminate in triumphant achievements—"positivism" (Comte), "civilization" (Morgan), "communism" (Marx and Engels), and societies "compounded" many times (Spencer). In this one respect, but only in this respect, these theories resembled the bioevolutionary model: biological species do not have to become extinct—even though many of them actually do—in the same sense that individuals have to die. However, these theories nevertheless reflect a life-cycle model, insofar as they involve one society after another following essentially the same pattern of development, just as one infant after another follows the same general route to adulthood. And they do not appear to involve, in any major way, the evolutionary mechanisms of random variation and selection. In fact, they are primarily theories of progress, not of evolution in any sense that biologists would recognize, regardless of the "evolutionary" label commonly attached to them (Nisbet 1969).

The social-evolutionary idea fell into disfavor among sociologists around the turn of the twentieth century, but was revived several decades later with, for example, Talcott Parsons' analysis of primitive, intermediate, and modern societies (1977), and Lenski and Lenski's (1982) analysis of transitions from hunting-and-gathering to horticultural, agrarian, and industrial societies. Although based on more accurate and more extensive facts than were available in the nineteenth century, these newer schemes pertaining to the evolution of whole societies are nevertheless basically similar to their nineteenth century predecessors in that they present various societies as passing through specific stages in a predominantly unidirectional pattern, which, as noted above, represents a divergence from the bioevolutionary model. This is not necessarily a defect: the development of societies of new types may simply not be a process to which concepts of a bioevolutionary sort are fully applicable.

Evolutionary concepts have been used not only in attempts to understand some social and cultural phenomena, as discussed above, but also in attempts to formulate and justify certain social policies. In the late nineteenth and early twentieth centuries, evolutionary concepts and associated slogans such as "survival of the fittest" appeared to provide rationales for what have been labelled "Social Darwinist" policies. Focusing on the selective (rather than on the random-variation) phase of the evolutionary process, various business, political, ideological, and military leaders in several countries, along with some scholars in several disciplines (including the sociologists Herbert Spencer and William Graham Sumner), emphasized the importance of the struggle for survival in maintaining a hardy population and a vigorous society, and opposed social welfare measures that they thought would mitigate that struggle. Supporters of this approach differed in several ways: some emphasized individual struggle, others, group (e.g., racial or national) struggle; some emphasized nonviolent means (e.g., economic competition), and others, armed conflict (see Hofstadter 1955).

A statement by Darwin himself illustrates the basic idea underlying "Social Darwinism." Although Darwin did not oppose smallpox vaccination, he worried about its effects: "There is reason to believe that vaccination has preserved thousands, who from a weak constitution would formerly have succumbed to smallpox. Thus the weak members of civilized societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man" (Darwin [1871] 1897, p. 134).

Darwin did not believe that war led to the selective survival of the fittest people, as he thought smallpox tended to do. Quite the opposite: he saw war as destroying "the finest" young men while those with "poor constitutions" would avoid fighting and thus survive and reproduce.

But evolutionary concepts can be applied at diverse levels. Nineteenth-century war might have led to the selective survival of societies or governments that were "fittest" in some sense, even if not to the survival of the "fittest" young men within particular societies. Some Social Darwinists adopted that perspective. Thus: "Storm purifies the air and destroys the frail trees, leaving the sturdy oaks standing. War is the test of a nation's political, physical and intellectual worth. The State in which there is much that is rotten may vegetate for a while in peace, but in war its weakness is revealed. . . . It is better to spend money on armaments and battleships than luxury, motormania and other sensual living" (Baron Karl von Stengel, cited by Angell 1911, p. 168).

There is a problem here: what an exceedingly powerful storm is most likely to leave standing are not sturdy oaks but blades of grass. And this leads to a question: what does "survival of the fittest" actually mean? Defining the fittest as "those who survive" would make the phrase tautological, but any other definition would very likely make it untrue except under a limited range of conditions. In any case, "fitness" is not necessarily equivalent to "desirability" as we might define that, or to what the people of a society actually desire.

The problem of defining "fitness" may be illustrated by examining what Darwin said about smallpox. Suppose people who would have succumbed to smallpox if not vaccinated, but who were actually saved by vaccination, have descendants who inherit their potential vulnerability to that disease. In this respect, such descendants might be considered relatively "unfit." But if these descendants are all protected from smallpox by vaccination, or if smallpox itself is permanently eliminated, then "potential vulnerability to smallpox" might have no practical implications and might not entail "unfitness" in any practically relevant sense.

If the term "Social Darwinism" is to be applied to attempts to improve society through competition and struggle that eliminate some variants while perpetuating others, then attempts to improve society by improving people within society (through education, health care, and so on) might reasonably be labelled "Social Lamarckism." The fact that Lamarckian ideas have been empirically disconfirmed and rejected in explanations of biological evolution has no bearing on the question of the reasonableness of analogous ideas in the socio-cultural realm. And, in both biological and socio-cultural contexts, Lamarckian and Darwinian ideas can logically coexist and have done so. Darwin himself accepted the validity of Lamarckian ideas in explaining biological evolution, even while he was developing different ideas of his own; the decisive rejection of Lamarckism by evolutionary biologists came after Darwin had died. And Herbert Spencer, who coined the Darwinian phrase "survival of the fittest" and has traditionally been considered a major Social Darwinist, has also been called a Social Lamarckist (Bowler 1995, p. 113) on the ground that he was more committed to struggle as a (Lamarckian) means for invigorating and improving the individuals who participate in it, than to struggle as a (Darwinian) means for eliminating the "unfit."

Partial artificial control over reproduction and hence over the evolutionary process is illustrated by methods used to develop new variants of farm animals, work animals, laboratory animals, and pets. Improvements in these methods have ultimately led to "cloning," which involves total and exact replication of individuals' inherited characteristics without mating. Control over human reproduction was sought on a limited basis by a "eugenics" movement that emerged in the late nineteenth century, founded by Darwin's cousin Francis Galton. This movement achieved some successes, including arrangements for sterilization of some criminals and mentally ill people in various jurisdictions. However, it also faced problems, including: lack of consensus about the traits to be targeted; complexities in the process of hereditary transmission (for example, the fact that parents may transmit to their offspring a defect that they do not manifest themselves); political and legal obstacles to compulsory eugenic measures in societies with well-established traditions of democracy and personal freedom; and, the difficulty of distinguishing between traits transmitted through heredity and traits transmitted through socialization. Supporters of eugenics did not always care about this last point: they sometimes assumed that preventing people with undesirable traits from having children would reduce the prevalence of people bearing these traits regardless of how the traits themselves were transmitted from one generation to the next.

The eugenics movement developed in a tragically racist direction. Some major leaders of the movement in the United States thought that white people of northern European ancestry constituted a superior race and regarded as genetically inferior the southern and eastern Europeans who were immigrating to the country in large numbers. The movement came to be discredited after its ideas came to be used in Hitler's Germany to support genocidal killings of Jews and members of various other groups.

references

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Maurice N. Richter, Jr.