 Even a necessary biconditional linking knowledge to some state j would probably not be sufficient for an analysis of knowledge, although just what more is required is a matter of some controversy. According to some theorists, to analyze knowledge is literally to identify the components that make up knowledge—compare a chemist who analyzes a sample to learn its chemical composition. On this interpretation of the project of analyzing knowledge, the defender of a successful analysis of knowledge will be committed to something like the metaphysical claim that what it is for S to know p is for some list of conditions involving S and p to obtain. Other theorists think of the analysis of knowledge as distinctively conceptual—to analyse knowledge is to limn the structure of the concept of knowledge. On one version of this approach, the concept knowledge is literally composed of more basic concepts, linked together by something like Boolean operators. Consequently, an analysis is subject not only to extensional accuracy, but to facts about the cognitive representation of knowledge and other epistemic notions. In practice, many epistemologists engaging in the project of analyzing knowledge leave these metaphilosophical interpretive questions unresolved; attempted analyses, and counterexamples thereto, are often proposed without its being made explicit whether the claims are intended as metaphysical or conceptual ones. In many cases, this lack of specificity may be legitimate, since all parties tend to agree that an analysis of knowledge ought at least to be extensionally correct in all metaphysically possible worlds. As we shall see, many theories have been defended and, especially, refuted, on those terms.