Ancient Society
In some cases criticism resulted in other, parallel three-age systems, such as the concepts expressed by Lewis Henry Morgan in "Ancient Society", based on ethnology. These disagreed with the metallic basis of epochization. The critic generally substituted his own definitions of epochs. Vere Gordon Childe said of the early cultural anthropologists:Last century Herbert Spencer, Lewis H. Morgan and Tylor propounded divergent schemes ... they arranged these in a logical order ... They assumed that the logical order was a temporal one... The competing systems of Morgan and Tylor remained equally unverified—and incompatible—theories.