Radical internalists insist that all content is narrow. A typical analysis holds that Oscar is thinking not about water but about some more general category of substance that subsumes XYZ, so that Oscar and Twin Oscar entertain mental states with the same contents.  Tim Crane (1991) and Gabriel Segal (2000) endorse such an analysis.  They hold that folk psychology always individuates propositional attitudes narrowly. A less radical internalism recommends that we recognize narrow content in addition to wide content. Folk psychology may sometimes individuate propositional attitudes widely, but we can also delineate a viable notion of narrow content that advances important philosophical or scientific goals. Internalists have proposed various candidate notions of narrow content (Block 1986; Chalmers 2002; Cummins 1989; Fodor 1987; Lewis 1994; Loar 1988; Mendola 2008). See the entry narrow mental content for an overview of prominent candidates.