 Mass expressions and their relations to count expressions, and how they are interpreted and employed by metaphysicians, offer us an interesting and voluminous case-study of recent metaphysics informed by lexical, semantic, and syntactic considerations. The careful student of this material can take away many cautionary tales, useful tools, and become aware of just how different the responses to the same linguistic data can be. This is a very difficult and woolly area of inquiry where there is little consensus. But interesting recent empirical work on mass and count expressions is being done which is shedding some new light on these issues, and there has been an explosion of recent work in linguistics which does seem to display genuine progress, the most fecund research being more heavily empirical than before. (For earlier empirically-informed work on this, see Casati 2005, and Frisson &amp; Frazier 2005. For more recent relevant work, see Husić 2020, Kiss et al 2021a, Kiss et al 2017; Goddard &amp; Wierzbicka 2014; Massam 2012; Moltmann 2020; and see the references mentioned in Pelletier 2012 p435).