Multilineal evolution is a 20th-century social theory about the evolution of societies and cultures. It is composed of many competing theories by various sociologists and anthropologists. This theory has replaced the older 19th century set of theories of unilineal evolution, where evolutionists were deeply interested in making generalizations.
When critique of classical social evolutionism became widely accepted, modern anthropological and sociological approaches have changed to reflect their responses to the critique of their predecessor. Modern theories are careful to avoid unsourced, ethnocentric speculation, comparisons, or value judgements; more or less regarding individual societies as existing within their own historical contexts. These conditions provided the context for new theories such as cultural relativism and multilinear evolution, which criticizes the generalization of culture and hypothetical stages of evolution.
History
Around 1940, a number of American anthropologists began rejecting the ideas of unilinear evolutionism and universal evolutionism, and began to move towards the idea of multilinear evolutionism. White thought in broad, universal schemes, while anthropologists such as Julian Steward preferred to use a more limited, multilinear strategy. Steward rejected the 19th century notion of progress, and instead called attention to the Darwinian notion of "adaptation," arguing that all societies had to adapt to their environment in some way, but that the process could differ between cultures. Julian Steward thus linked multilinear evolution with the idea of cultural ecology.
Cultural evolution had previously been treated much like biological evolution, but many anthropologists were quick to dismiss this comparison. Steward wrote that unlike biological evolution, in cultural evolution it is assumed that cultural patterns in different parts of the world are genetically unrelated, and yet they were said in unilinear evolution to pass through parallel sequences.
The multilineal evolutionary theory views the process of cultural development as an adaption to nature's resources through technological breakthroughs, as well as coping with outside cultural influence.