Mass terms are those such as ‘water’, ‘computer software’, ‘advice’, and ‘knowledge’. They are contrasted with count terms such as ‘person’, ‘computer program’, ‘suggestion’, and ‘belief’. Intuitively, mass terms refer to “stuff” while count terms refer to “objects”. Since mass terms refer to stuff, they (but not count terms) allow for measurement: ‘a liter of water’, ‘three CDs worth of computer software’, ‘too much advice’, ‘many books worth of deep knowledge’. Since count terms refer to objects, they (but not mass terms) allow for counting, quantifying and individuating: ‘a person’, ‘three computer programs’, ‘each suggestion’, ‘that belief of his’.

The presumed fact that mass nouns are not true of individuals has seemed to some to show that traditional logical theory is inadequate as a medium for their semantic representation. It has seemed implausible to represent ‘Snow is white’ as ∀x(Snow(x)→White(x)), since there are no plausible values for x. (What could be the value of x in ‘For each x, if x is snow then x is white’?) In turn, this has been the driver for the use of mereological-based approaches to the semantics of mass terms. (‘Mereology’ is here to be understood widely to include not only classical mereology, but a range of approaches that share some features with the classical mereology.)

Further philosophical problems traditionally associated with mass terms include distinguishing mass from count terms (is it a syntactic or semantic distinction?), deciding the extent of the classification (does it include more than noun phrases?), describing the semantic underpinnings of mass terms (since they are not true of individuals, how can a model theory be developed?), and explaining the ontology presupposed by mass terms vs count terms.

Alongside these concerns, there is the meta-philosophical question of the extent to which the linguistic practices of a language can be used as evidence for how those speakers view reality, or indeed, what reality is. It is this issue, as applied to the question of the ontology presupposed by mass terms vs count terms, that I wish especially to address.

I am going to restrict my attention to the category of nouns and noun phrases, even though some writers have noted parallels between count terms and event-verbs and between mass terms and process-verbs. Others have noted how aspectual distinctions sometimes mirror the mass/count distinction in nouns: one can eat dinner for an hour (eating dinner is mass-like; and the temporal modification is not punctual), but it seems nonsensical to eat a dinner for an hour (eating a dinner is count-like, but this does not happily combine with non-punctual temporal modification). Some writers have argued that some adjectives can be classified as count or mass: for instance, ‘triangular’ might be count, ‘watery’ might be mass. I think many of my observations within the nominal domain might carry over to these other categories, but I don't wish to argue for that here.

Throughout the recent history of philosophical and linguistic reflections on the mass/count distinction, there have been skeptics who disparage the attempt to make the distinction carry any semantic weight or philosophical importance. Such skeptics point to the fact that the same meaning can be count in one language but mass in another, even in very closely related languages. Furthermore, some languages, especially the Sino-Japanese-Korean ones, have been argued to assign mass to all lexical nouns. There are also some Amerindian languages that seem to have no mass/count distinction at all. The skeptics also point to pairs of terms within one language where one is count and the other mass, yet they seem to designate very similar items of reality—for instance, ‘brownie’ vs. ‘baklava’—or sometimes even the same item of reality—for instance, ‘this suggestion’ vs. ‘this advice’. (Or, to consider a more philosophically relevant example: ‘belief’ is a count term while ‘knowledge’ is a mass term. Yet we commonly think that what is one and the same thing can be a belief of Sandy's but knowledge of Kim's; and that before Kim had enough evidence to make it be knowledge, it was a belief of Kim's.) Still others, myself included, have argued that (almost?) all nouns can be employed in both a mass and a count manner, showing that some very fancy footwork is required in order to give a reasonable semantic and ontological accounting for this.

I too am a skeptic about the viability of using the mass/count distinction to draw any firm metaphysical/ontological conclusions. However, I am not a skeptic about the individual/stuff distinction—it is just that I don't think it parallels the mass/count distinction. And I want to describe some ways that one might take to de-couple the two.

One way I want to proceed is to cast doubt on the assignment of mass/count to lexical nouns, and I will argue instead for the view that they should be assigned only at the level of noun phrases. (Following the suggestions made by Keith Allen (1980).) But in addition to these syntactic moves, we need to deal with the semantic consequence of (what I presume to be) the fact that every noun is sometimes used in a count manner and sometimes in a mass manner. Solutions in the literature postulate a number of ‘conversion functions’ or ‘coercions’ that will convert the meaning of ‘chicken’ (+count) to the meaning of ‘chicken’ (+mass). I think these are all misguided, and wish to give a plausible replacement account.