In this entry I will attempt to explain the difference between a bare particular and an Aristotelian primary substance. A subsequent post will consider whether this difference is theologically relevant, in particular, whether it is relevant to the theology of the Incarnation.
What is a Particular?
Particulars in the sense relevant to understanding 'bare particular' may be understood in terms of impredicability. Some things can be predicated of other things. Thus being black can be predicated of my cat, and being a property can be predicated of being black; but my cat cannot be predicated of anything. My cat is in this sense 'impredicable.' Particulars are subjects of predication but cannot themselves be predicated. Particulars, then, are ultimate subjects of predication. Thus my cat is an ultimate subject of predication unlike being black which is a subject of predication, but not an ultimate subject of predication. Particulars have properties but are not themselves properties. Properties may be characterized as predicable entities.
Three Senses of 'Bare Particular'
1. The first sense I mention only to set aside. It is a complete misunderstanding to suppose that philosophers who speak of bare or thin particulars, philosophers as otherwise different in their views as Gustav Bergmann, David Armstrong, and J. P. Moreland, mean to suggest that there are particulars that have no properties and stand in no relations. There is no such montrosity as a bare particular in this sense.
In order to explain the two legitimate senses of 'bare particular' I will first provide a general characterization that covers them both. A bare particular is a particular that lacks a nature or (real) essence. It is therefore quite unlike an Aristotelian primary substance. Every such substance has or rather is an individual nature. But while lacking a nature, a bare particular has properties. This 'having' is understood in terms of the asymmetrical external nexus of exemplification. A bare particular is thus tied to its properties by the external nexus of exemplification. To say that the nexus that ties a to F-ness is external is to say that there is nothing in the nature of a, and nothing in the nature of F-ness to require that a exemplify F-ness. After all, a, as bare, lacks a nature, and F-ness, while it has a nature, is not such that there is anything in it to necessitate its being exemplified by a. In this sense a bare particular and its properties are external to each other.
This mutual externality of property to bearer entails what I call promiscuous combinability: any bare particular can exemplify any property, and any property can be exemplified by any bare particular. (A restriction has to be placed on 'property' but we needn't worry about this in the present entry.)
David Armstrong holds that (i) there are conjunctive properties and that (ii) for each bare or thin particular there is the conjunctive property that is the conjunction of all of the particular's non-relational properties. He calls this the particular's nature. But I will avoid this broad use of 'nature.' What I mean by 'nature' is essence. Bare particulars lack essences, but not properties. Therefore, no property or conjunction of properties on a bare-particularist scheme is an essence. Note that it is given or at least not controversial that particulars have properties; it is neither given nor uncontroversial that particulars have essences.
I should also point out that talk of Aristotelian natures or essences would seem to make sense only within a constituent ontology such as Aristotle's.
From the foregoing it should be clear that to speak of a particular as bare is not to deny that it has properties but to speak of the manner in which it has properties. It is to say that it exemplifies them, where exemplification is an asymmetrical external tie. To speak of a particular as an Aristotelian substance is also to speak of the manner in which it has properties.
Consider the dog Fido. Could Fido have been a jellyfish? If Fido is a bare particular, then this is broadly logically possible. Why not, given promiscuous combinability? Any particular can 'hook up' with any property. But if Fido is an Aristotelian substance this is not broadly logically possible. For if Fido is a substance, then he is essentially canine. In 'possible worlds' jargon, Fido, if a substance, is canine in every possible world in which he exists. What's more, his accidental properties are not such as to be exemplified by Fido -- where exemplification is an external tie -- but are rather "rooted in" and "caused" by the substance which is Fido. (See J. P. Moreland who quotes Richard Connell in Moreland's Universals, McGill-Queen's UP, 2001, p. 93) The idea is that if Fido is an Aristotelian substance, then he has ingredient in his nature various potentialities which, when realized, are manifestations of that nature. The dog's accidental properties are "expressions" of his "inner nature." They flow from that nature. Thus being angry, an accident of Fido as substance, flows from his irascibility which is a capacity ingredient in his nature. If Fido is a bare particular, however, he would be externally tied to the property of being angry. And he would also be externally tied to the property of being a dog.
It follows that if particulars are bare, then all of their properties are had accidentally, and none essentially.
We now come to the two legitimate senses of 'bare particular.'
2. The second sense of 'bare particular' and the first legitimate sense is the constituent-ontological sense. We find this in Bergmann and Armstrong. Accordingly, a bare particular is not an ordinary particular such as a cat or the tail of a cat or a hair or hairball of cat, but is an ontological factor, ingredient, or constituent of an ordinary particular. Let A and B be round red spots that share all qualitative features. For Bergmann there must be something in the spots that grounds their numerical difference. They are two, not one, but nothing qualitative distinguishes them. This ground of numerical difference is the bare particular in each, a in A, and b in B. Thus the numerical difference of A and B is grounded in the numerical (bare) difference of a and b. In one passage, Bergmann states that the sole job of a bare particular is to individuate, i.e., to serve as the ontological ground of numerical difference.
Particulars, unlike universals, are unrepeatable. If F-ness is a universal, F-ness is repeated in each F. But if a is F, a is unrepeatable: it is the very particular it is and no other. One of the jobs of a Bergmannian bare particular is to serve as the ontological ground of an ordinary particular's particularity or thisness. A Bergmannian bare particular is that ontological constituent in an ordinary particular that accounts for its particularity. But note the ambiguity of 'particularity.' We are not now talking about the categorial feature common to all particulars as particulars. We are talking about the 'incommunicable' thisness of any given particular.
3. The third sense of 'bare particular' and the second legitimate sense is the nonconstituent-ontological sense. Summing up the above general characterization, we can say that
A bare particular is a particular that (i) lacks a nature (in the narrow sense lately explained); (ii) has all of its properties by exemplification where exemplification is an asymmetrical external nexus; and as a consequence (iii) has all of its properties accidentally, where P is an accidental property of x iff x exemplifies P but can exist without exemplifying P.
Note that this characterization is neutral as between constituent and nonconstituent ontology. If one is a C-ontologist, then bare particulars are constituents of ordinary particulars. If one is an NC ontologist who rejects the very notion of an ontological constituent, then bare particulars are ordinary particulars.
I have explained the difference between a bare particular and an Aristotelian substance. In a subsequent post I will address the question of how this deep ontological difference bears upon the possibility of a coherent formulation of the Incarnation doctrine.