It is just because civilization is ever evolving, changing, and becoming more complicated, that experts find it so difficult to define it in explicit terms.
Arthur KeithBefore the discovery of agriculture mankind was everywhere so divided, the size of each group being determined by the natural fertility of its locality.
Arthur KeithGood men, whether they be Christians or rationalists, do not desire to discriminate between races, but the distinctions implanted by Nature are too conspicuous to escape the observation of our senses.
Arthur Keith