The fundamental criterion of "Chinese-ness," anciently and throughout history, has been cultural. The Chinese have had a particular way of life, a particular complex of usages, sometimes characterized as "li". Groups that conformed to this way of life were, generally speaking, considered Chinese. Those that turned away from it were considered to cease to be Chinese. ... It was the process of acculturation, transforming barbarians into Chinese, that created the great bulk of the Chinese people. The barbarians of Western Chou times were, for the most part, future Chinese, or the ancestors of future Chinese. This is a fact of great importance. ... It is significant, however, that we almost never find any references in the early literature to physical differences between Chinese and barbarians. Insofar as we can tell, the distinction was purely cultural.