typology, system of groupings (such as “landed gentry” or “rain forests”), usually called types, the members of which are identified by postulating specified attributes that are mutually exclusive and collectively exhaustive—groupings set up to aid demonstration or inquiry by establishing a limited relationship among phenomena. A type may represent one kind of attribute or several and need include only those features that are significant for the problem at hand.
Because a type need deal with only one kind of attribute, typologies can be used for the study of variables and of transitional situations. Classifications, on the other hand, deal with “natural classes”—i.e., with groupings that differ from other groupings in as many particulars as one can discover. For this reason classifications can be only a preliminary step in the study of variables, for they cannot deal elegantly with transitional situations in which variables are to be expected. The more gradual the change, the fewer are the distinctive features upon which to define natural classes and the more difficult it becomes to draw a line between classes. In this situation typologies may be invoked.
When the problem is simply that of ordering unconditioned phenomena, it is difficult to distinguish typologies from classifications. The latter have been considered preliminary to the discovery of sequences or laws. Because typologies invariably use ordering for additional purposes, classifications can be regarded as typologies that are limited to the problem of order. Typologies, subsisting usually on the frontiers of research, are less durable than classifications in that their descriptions are accepted only to the degree that they continue to provide solutions to problems.
A typology elicits a particular order depending on the purposes of the investigator and on the phenomena so arranged, an order that limits the ways in which the data can be explained. There can be different interpretations of the relations of the phenomena. The Linnaean system for setting up divisions in biology is an ordering that was only later found to be in accord with biological evolution. In social and cultural studies, in which the significant distinctions are not of the genus and species kind, this kind of ordering has been less successful.
Typologies are characteristic of the social sciences and have had a great development in archaeology. Arne Furumark, a Swedish archaeologist, regards typologies as applicable to archaeology because of the inertia of the human mind, which usually views the undisturbed development of material culture as taking place gradually. This view has been contrasted with the “Swedish typology” of B.E. Hildebrand and Oscar Montelius, which sees cultural material as produced through a process analogous to that of organic evolution—a view that might be a step toward delineating processes of interaction and development per se, regardless of the sources of the material.
In anthropology and archaeology, typological systems may be based on variations of style or artifacts, paintings, buildings, burial customs, social systems, or ideologies. Christian Jürgensen Thomsen, a Danish antiquary, used a typology of materials to establish his celebrated Stone, Bronze, and Iron ages. Later the Stone Age was subdivided by L.L. Gabriel de Mortillet, a French anthropologist. Subsequently, typologies, combined with careful stratigraphic work, were used to conceptualize elements changing through time, to fill stratigraphic gaps, and to extrapolate strata. A seriation technique, called sequence dating, based on shared typological features, enabled Sir Flinders Petrie to establish the temporal order of a large number of Egyptian graves.
Some typologies go beyond the problem of order and help to show the importance of particular factors. Comparisons among examples of a single type rely on the postulated constancy of the type in order to focus on variable factors and to suggest explanations of those variations. Two sequences of identical types may show differences in proportions or in rates of change, leading to additional inferences, such as the assumption of a causal relation.
Large-scale typologies may assume that certain factors are of overriding significance. Where ordering is chronological, there are the developmental stages of the social evolutionist Lewis Henry Morgan or the repetitive sequences of the philosophers of history Oswald Spengler and Arnold Toynbee. Where time is of less concern, there are such constructs as the leisure class of the American economist Thorstein Veblen; the inner- and other-directed personality types of David Riesman, a Harvard sociologist and publicist; and the polar cultural types of Sir Henry Maine, Ferdinand Julius Tönnies, and Robert Redfield.