Analytic classification consists of forming successive series of classes, referring to different features of artifacts. Each class is characterized by one or more attributes which indicate a custom to which the artisan conformed, for example, a technique of manufacture, or a concept which he expressed in the artifacts, such as a design. These customs and concepts constitute modes. They are “procedural modes” when they refer to behavior of artisans and “conceptual modes” when they consist of ideas which artisans have expressed in artifacts.
Taxonomic classification consists of formulating a single set of classes, one for each kind of artifact in the collection. Each class is characterized by two or more modes, selected from among the total number of modes obtainable by means of analytic classification. The modes diagnostic of each class constitute its type. If diagnostic modes are selected for their time-space significance, the resultant types are “historical.” If the diagnostic modes are selected for what they indicate about the intrinsic nature of the artifacts, the types are “descriptive.”
The situations under which it is best to use either procedural or conceptual modes or historical or descriptive types are discussed and it is concluded that all four kinds of units are essential for the complete interpretation of archaeological remains.