 As Aydede (2000) and Schneider (2011) emphasize, denotational individuation is unsatisfying. Co-referring words may play significantly different roles in mental activity. Frege’s (1892 [1997]) famous Hesperus-Phosphorus example illustrates: one can believe that Hesperus is Hesperus without believing that Hesperus is Phosphorus. As Frege put it, one can think about the same denotation “in different ways”, or “under different modes of presentation”. Different modes of presentation have different roles within mental activity, implicating different psychological explanations. Thus, a semantically permeated individuative scheme adequate for psychological explanation must be finer-grained than denotational individuation allows. It must take mode of presentation into account. But what it is to think about a denotation “under the same mode of presentation”? How are “modes of presentation” individuated? Ultimately, semantically permeated theorists must grapple with these questions. Rescorla (forthcoming) offers some suggestions about how to  proceed.[11]