Abstract

It is by now a commonplace that the classification of sciences into nomological and ideographical, which originated with Windelband, is neither exhaustive nor exclusive. Rather, there are sciences in which nomothetical activities are prevalent and there are sciences in which ideographical efforts dominate. A third kind of enterprise is widespread throughout most, if not all, sciences: typological undertakings. In some sciences these are the most important and dominant projects. Linguistics tries to establish types of expressions: phonemes, morphemes, syntactical categories. History of art endeavors to set up various styles, i. e., types of art. General history attempts at well founding of such notions as revolution, reaction, buonapartism, findesieclism. When a historian declares that a revolution starts when a housewife cannot buy a chicken on the market, he divides the stream of events into periods according to a criterion that seems to him important, establishes similarities between different periods, and classifies them into types. Such typological activities are common not only in social sciences and humanities but also in physics which speaks about explosions, collisions, changes from a positive to a negative acceleration. A mathematician often enters into a typological venture, e.g., when he analyzes a function as increasing in an interval or describes it as concave upward in another interval. Typology may be conceived as containing the theory of classification. But there are typological problems that are not included in the theory of classification. A classification is performed on a class when its subclasses are defined. Typology, as suggested by the examples, may take a single object and try to conceive it as a summation of its fragments. To find a segmentation suitable from some point of view is not a classification. Rather, classification presupposes segmentation.