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.
[2] This theory focused around the process that culture moves forward down a number of paths consisting of different styles and lengths.
[4] Anthropologists Marshall Sahlins and Elman Service wrote a book, Evolution and Culture, in which they attempted to synthesize White's and Steward's approaches.
[1] Sahlins and Service also dismissed this comparison, stating that cultural variation could be transmitted between different lines by diffusion, where biological evolution cannot.
"[3] While each anthropologist's theory regarding multilineal evolution has varied slightly, most agreed that no specific evolutionary changes are experienced by all cultures universally, but that all human societies do generally evolve or progress.
[citation needed] As a result, the simplistic notion of 'cultural evolution' has grown less useful and given way to an entire series of more nuanced approaches to the relationship of culture and environment.