Hardly anyone reads Gustav Bergmann any more, but he is well worth reading. It is interesting to compare his style of ontological analysis with that of the great hylomorphic ontologists, Aristotle and Aquinas. The distinguished Aristotelian Henry B. Veatch does some of my work for me in a fine paper, "To Gustav Bergmann: A Humble Petition and Advice" in M.S.Gram and E.D.Klemke, eds. The Ontological Turn: Studies in the Philosophy of Gustav Bergmann (University of Iowa Press, 1974, pp. 65-85)
I want to focus on Veatch's comparison of Aristotle and Bergmann on the issue of prime matter versus bare particulars. As Veatch correctly observes, "all of the specific functions which bare particulars perform in Bergmannian ontology are the very same functions as are performed by matter in Aristotle . . . ." (81) What are these functions?
1) One of the jobs bare particulars (BPs) perform is that of ontological individuator, in classical parlance, that of principium individuationis. Take a typical Bergmannian example, an 'Iowa example,' if you will. There are two round, red spots on a piece of paper. The spots are identical in respect of size, shape, and (shade of) color. But there are two of them. On Bergmann's 'assay' of the situation, there are two particulars and three universals such that each of the particulars exemplifies all three universals. Since the spots are the same in respect of the universals they exemplify, there is need of a differentiating/individuating factor, and this is the particular 'in' each spot. But the particular in each spot is 'bare' in the sense that, in and by itself, it is propertyless. No doubt BPs exemplify properties and cannot exist without exemplifing properties; but in themselves they are bare of properties. But what does this mean exactly?
Although BPs exist only as exemplifying universals, there is nothing in the nature of a BP to dictate that it exemplify any particular universal: BPs have no nature. This is what makes them bare. BPs and first-order universals are promiscuously combinable, if you will. BPs, being in themselves devoid of properties, differ among themselves solo numero: their difference is bare numerical difference. This equips them to serve as the individuators or differentiators of 'ordinary' particulars which on Bergmann's assay are composites built up out of universals and bare particulars. BPs are the ontological grounds of numerical difference. Thus BPs do the same job that matter does in Aristotle.
You have not understood the notion of a bare particular if you think that they are bare of properties. They cannot exist without properties. Nothing can. What makes them bare is that there is nothing in their nature to dictate which properties they have.
2) A second job of bare particulars is to serve as substratum or support of properties. Properties are predicable entities; particulars are not. A bare particular 'in' an ordinary particular is the ontological ground of its being impredicable. For Veatch, Aristotelian matter plays a similar role:
Likewise, for Aristotle, it is presumably just because primary substances are material that they are unable to be, as Aristotle says, either 'present in' or 'predicable of' a subject. But could one not say just the same thing of Bergmann's bare particulars? They are neither present in nor predicable of a subject. (81)
3) Bare particulars are intrinsically indeterminate, but determinable, where universals function as determinations much as forms do for an Aristotelian. "In short, they [BPs] are to the characters [universals] which they exemplify much as potency is to act or as matter to form." (81)
Veatch Contra Bergmann
Veatch now lodges a reasonable complaint against Bergmann. How could "matter or bare particulars [be] among the ultimates that one arrives at in a process of analysis. . ."? "For how could anything which in itself is wholly indeterminate and characterless ever qualify as a 'thing' or 'existent' at all?" (81) On Bergmann's assay, an ordinary particular has more basic entities as its ontological constituents. But if one of these constituents is an intrinsically indeterminate and intrinsically characterless entity, how could said entity exist at all, let alone be a building block out of which an ordinary particular is constructed?
For Veatch, form and matter are not ontological atoms in the way bare particulars and simple universals are ontological atoms for Bergmann. "Matter and form are not beings so much as they are principles of being." (80) 'Principle' is one of those words Scholastics like to use. Principles in this usage are not propositions. They are ontological factors invoked in the analysis of primary substances, but they are not themselves primary substances. They cannot exist on their own. Let me try to make Veatch's criticism as clear as I can.
An ordinary particular is a this-such. The thisness in a this-such is the determinable element while the suchness is the determination or set of determinations. Veatch's point against Bergmann is not that ordinary particulars are not composites, this-suches, or that the thisness in a this-such is not indeterminate yet determinable; his point is that the determinable element cannot be an ontological atom, an entity more basic than the composite into which it enters as ontological building block. The determinable element cannot be a basic existent; it must be a principle of a basic existent, where the basic existent is the this-such.
This implies, contra Bergmann, that what is ontologically primary is the individual substance, the this-such, which entails that matter and form in an individual substance cannot exist apart from each other. They are in some sense 'abstractions' from the individual substance. The form in a material this-such is not merely tied to matter in general, in the way that Bergmannian first-order universals are tied to bare particulars in general; the form is tied to the very matter of the this-such in question. And the same goes for the matter: the designated matter (materia signata) of Socrates cannot exist apart from Socrates' substantial form.
Veatch says that Bergmann cannot have it both ways: "His bare particulars cannot at one and the same time be utterly bare and characterless in the manner of Aristotelian prime matter and yet also be 'things' and 'existents' in the manner of Aristotelian substances." (82-83)
Tentative Assessment
Veatch's point against Bergmann has merit, and I believe it can be adapted as a criticism of David Armstrong's thin particulars. There is no difference that I can see between a Bergmannian BP and an Armstrongian TP. (Armstrong gives no evidence of having read Bergmann carefully, so I discount his claim that his TPs are different from Bergmann's BPs.)
But is Veatch's view really any better? What is the ontological status of his 'principles' form and matter? Their status is unclear. They cannot exist on their own, nor can they have the 'building block' status of Bergmann's ontological atoms. Thus they don't 'promiscuously combine' as Bermann's BPs and first-order universals do. So in some sense they are abstractions isolated by the mind of the ontologist. And yet they have a fundamentum in re.
They therefore seem as murky as Bergmann's bare particulars. And so we hit another impasse.