Diffusion and Independent Invention: a Critique of Logic1

H E R E exists a large proportion of anthropological data which admits of no clear-cut methodology but is usually handled according to inference and common sense logic. While this method may be soundly rational, the possibility of an enormous subjective clement and fallacious logic is ever present and is demonstrated by the existence of the diffusion controversy. This controversy is made possible not only by the personal bias of the investigator but also by a confusion of the principles upon which the solution is based. It is not my purpose to present a rule-of-thumb method for the settlement of the diffusion controversy but to inquire into its logical implications and discover whether these are not capable of formulation. While this will but formulate the principles implicit i n most work, i t will also reveal the possibility of certain confusions and inconsistencies. Certain factors are involved in every instance where there is doubt concerning independent inven tion or diffusion: the spatial proximity of the localities where the‘ culture clement in question occurs, the apparent uniqueness of the element, the possibility of its derivation from a common ancestral culture, and the number of other elements shared by the localities. While all of these are usually taken into consideration through a method of common sense logic, certain of them are frequently ignored or one made to depend upon another in an illogical manner. This may be illustrated by inverted speech2 which occurs in North America in the Plains area, California, and the Southwest, and also occurs in Australia. Shall we account for these four occurrences by diffusion or independent invention? The solution depends upon inference from the assembled facts, but what is the T