In recent years there has been a trend toward employing mathematical information theory to formulate ideas about information in the fields of classification (Duncan and Estabrook 1976; Voss, Estabrook, and Voss 1983), philosophy of science (Rosenkrantz 1977), and even in the theory of knowledge (Dretske 1981). A similar application could be especially appropriate here, where we are concerned with informative typologies, because the concise expression that it gives to otherwise vague intuitions may allow us to see implications and connections between them that are not otherwise apparent.

Perhaps the most important intuition, to begin with, is that typologies like the Nubian Pottery Typology are developed primarily so that they will yield data that are useful for estimation, which means that the typologies are informative about those things that they are designed to estimate. Related theses are that the attributes, in terms of which the types are described, are informative about the types (with diagnostic attributes being the most informative), and that objectivity is useful to the extent that estimates based on objective data are better than estimates that are subjectively based.

The present chapter will sketch a way of formulating the above and other, related ideas information-theoretically. Our approach adapts to the typological case, and to the Nubian Pottery Typology in particular, certain methods that were earlier applied by EWA (1966) to quantitative measurement. This involves the application of information-theoretic concepts to typological propositions, expressed in the language of formal logic.