Published online by Cambridge University Press: 28 February 2022
Philosophers tend to view the relationship between a particular scientific theory and its data as representable by means of a single logical structure. The relationship is not ordinarily viewed as requiring a hierarchy of structures of different logical type. Two recent and excellent books illustrate this tendency. Glymour in Theory and Evidence (1980) continues the positivist tradition of viewing theories as axiomatic systems which connect with their evidence by means of ordinary quantification and truth functional connectives. Theory testing can be understood in terms of the syntactic properties of a single logical system. In The Scientific Image (1980), van Fraassen adopts a version of what is sometimes called the “semantic view”: a theory is a set of models of some purely formal system. Evidence constitutes (if confirmatory) a sub-model imbedded in a model of the equivalence class that is the theory.