 Abstract mass nouns, if they do refer, do not, prima facie, refer to physical stuffs or hunks of stuff. And the possibility of propositional or ‘abstract stuff’ strikes many, if it strikes them at all, as dubious—but it is not clear what is problematic about it. (Some work on abstract mass nouns can be found in Goddard &amp; Wierzbicka 2014; Husić 2020; Hinterwimmer 2020; Moltmann 2013, esp. 1.6; Nicolas 2002, 2003, and 2010; and Zamparelli 2020. See Treanor 2013, esp. p10, for an applied discussion which relates, and see Koslicki 1999, 68–9 for a rejection of the parallel between some abstract mass nouns and concrete mass nouns). More on abstract mass nouns can be found in  this section  of the entry on the Logic of Mass Expressions.