Unilineal evolution

Unilineal evolution, also referred to as classical social evolution, is a 19th-century social theory about the evolution of societies and cultures. It was composed of many competing theories by various anthropologists and sociologists, who believed that Western culture is the contemporary pinnacle of social evolution. Different social status is aligned in a single line that moves from most primitive to most civilized. This theory is now generally considered obsolete in academic circles.

Theories of social and cultural evolution are common in modern European thought. Prior to the 18th century, Europeans predominantly believed that societies on Earth were in a state of decline. European society held up the world of antiquity as a standard to aspire to, and ancient Greece and ancient Rome produced levels of technical accomplishment which Europeans of the Middle Ages sought to emulate. At the same time, Christianity taught that people lived in a debased world fundamentally inferior to the Garden of Eden and Heaven. During the Age of Enlightenment, however, European self-confidence grew and the notion of progress became increasingly popular. It was during this period that what would later become known as 'sociological and cultural evolution' would have its roots.

The Enlightenment thinkers often speculated that societies progressed through stages of increasing development and looked for the logic, order and the set of scientific truths that determined the course of human history. Georg Wilhelm Friedrich Hegel, for example, argued that social development was an inevitable and determined process, similar to an acorn which has no choice but to become an oak tree. Likewise, it was assumed that societies start out primitive, perhaps in a Hobbesian state of nature, and naturally progress toward something resembling industrial Europe.

While earlier authors such as Michel de Montaigne discussed how societies change through time, it was truly the Scottish Enlightenment which proved key in the development of cultural evolution. After Scotland's union with England in 1707, several Scottish thinkers pondered on the relationship between progress and the 'decadence' brought about by increased trade with England and the affluence it produced. The result was a series of conjectural histories. Authors such as Adam Ferguson, John Millar, and Adam Smith argued that all societies pass through a series of four stages: hunting and gathering, pastoralism and nomadism, agricultural, and finally a stage of commerce. These thinkers thus understood the changes Scotland was undergoing as a transition from an agricultural to a mercantile society.

Philosophical concepts of progress (such as those expounded by the German philosopher G.W.F. Hegel) developed as well during this period. In France authors such as Claude Adrien Helvétius and other philosophers were influenced by this Scottish tradition. Later thinkers such as Comte de Saint-Simon developed these ideas. Auguste Comte in particular presented a coherent view of social progress and a new discipline to study it: sociology.

These developments took place in a wider context. The first process was colonialism. Although Imperial powers settled most differences of opinion with their colonial subjects with force, increased awareness of non-Western peoples raised new questions for European scholars about the nature of society and culture. Similarly, effective administration required some degree of understanding of other cultures. Emerging theories of social evolution allowed Europeans to organize their new knowledge in a way that reflected and justified their increasing political and economic domination of others: colonized people were less-evolved, colonizing people were more evolved. The second process was the Industrial Revolution and the rise of capitalism which allowed and promoted continual revolutions in the means of production. Emerging theories of social evolution reflected a belief that the changes in Europe wrought by the Industrial Revolution and capitalism were obvious improvements. Industrialization, combined with the intense political change brought about by the French Revolution and US Constitution which were paving the way for the dominance of democracy, forced European thinkers to reconsider some of their assumptions about how society was organized.

Eventually, in the 19th century, three great classical theories of social and historical change were created: the social evolutionism theory, the social cycle theory and the Marxist historical materialism theory. Those theories had one common factor: they all agreed that the history of humanity is pursuing a certain fixed path, most likely that of the social progress. Thus, each past event is not only chronologically, but causally tied to the present and future events. Those theories postulated that by recreating the sequence of those events, sociology could discover the laws of history.

While social evolutionists agree that the evolution-like process leads to social progress, classical social evolutionists have developed many different theories, known as theories of unilineal evolution. Social evolutionism was the prevailing theory of early socio-cultural anthropology and social commentary, and is associated with scholars like Auguste Comte, Edward Burnett Tylor, Lewis Henry Morgan, and Herbert Spencer. Social evolutionism represented an attempt to formalize social thinking along scientific lines, later influenced by the biological theory of evolution. If organisms could develop over time according to discernible, deterministic laws, then it seemed reasonable that societies could as well. This really marks the beginning of Anthropology as a scientific discipline and a departure from traditional religious views of "primitive" cultures.