In terms of the views mentioned above, just where to locate a given theory or theorist along both of these dimensions—a substantive versus a semantic orientation; a subject versus attributor conception of context—is not always clear. In current work in epistemology, ‘contextualism’ is used to refer to either of these now more clearly distinguished threads, with the discussion of each going on largely in separation from the other. Thus, on the substantive side, we have Michael Williams (1991, 2001), whose concern is with providing an alternative to “epistemological realism”. According to the latter view, exemplars of knowledge and/or justified belief have some underlying “structural unity” that makes them all instances of a particular kind (1991, 108–109), independently of any “situational, disciplinary and other contextually variable factors” (ibid., 119; 2001, 159ff.). By contrast, as defended by Williams, contextualism—which he sees as present in Dewey, Popper, Austin, and Wittgenstein, for example—is the view that it is only in relation to the latter type of factors that a proposition has any epistemic status at all (ibid.), and that there is no need to suppose that the objects of epistemological inquiry have some underlying unity. Meanwhile, on the semantic side, we have a number of figures, all of whom emphasize moreover the importance of facts about the attributor of “knowledge”—such things as “the purposes, intentions, expectations, presuppositions, etc., of the speakers who utter these sentences” (Cohen, 1999, 187–188; cf. DeRose, 1992, 1995, 2009; Heller, 1999b, 117ff.)—in affecting what is expressed by a given utterance of a ‘knowledge’ sentence.