The Basic structure of Reality: Universals and Particulars

Realism, Nominalism, Conceptualism

Extrinsic Identity and the Problem of Universals

Q1: If the properties of an object represent everything knowable about it, can two distinct objects have the same properties -- and if so , how.

To say that two objects are distinct is just to say that there are two objects. Q1 could be restated as: "how can two things be distinct, but not different ?". This is a live issue -- it seems perfectly possible for two identical (non-different) things to be distinct -- indeed science maintains that every electron in the universe is distinct.

The solution famously proposed by Plato was this: if you have two peas which are as alike as the proverbial two peas in a pod, they both partake in the Form, the universal of pea-ness (or they partake in whatever universals correspond to all the properties they share).

So far, this is not really telling us why they are distinct, although it certainly tells us that the two peas are the same. A mere bundle of properties is not enough. We need to add something else, that gives each pea its own individuality. That something is called a bare particular (BP). We now 'construct' the pea out of a BP and instances of all the properties it has. The two peas have different (or distinct) BP's, which allows them to be distinct, although all their properties are the same. BP's are rather mysterious things; they have no identity of their own, yet they lend additional identity to whatever they are part of.

We also have another problem; that of understanding what the relationship is between the universal, the Platonic Form, and the particulars, the peas. aristotle did not like Plato's transcendental forms, and tried to bring them down to earth by planting them in the object itself. But this creates problems of its own. For instance, if a property is wholly present in every individual that display it, why is it not destroyed when we destroy one of its instancces ? Why doesn't destroying one green pea, destroy all the greenness in the world ? On top of that we still have the BP problem -- and a third problm. Not a all properites belong to a single individual; some are mutually held 'between' individuals. We call them relations(ship)s.

(If you don't believe in relations, please read this.) The problem is that if properties have to reside in individual objects, where do relations reside ? Plato seems to able to handle this better.

So can we say anything about the troublesome nature of properties, qua universals of Forms ? One of the things to note about universals is that they continue to exist (in whatever sense they exist) even after all the individuals objects exemplifying them have been destroyed. This gives us a clue that maybe univesals are possibilities. This would explain both how they can endure not being exemplified by any exisitng thing, and also how they can exist 'outside' of space and time. The possibility of greenness is not somehting that belongs to a particular place and time. And the BP ? Well, the ability of two things to be similar-but-distinct seems to have a lot to do with space (and perhaps time as well).

What makes the two peas distinct is that they are in different places.

However, that does not entirely solve the problem. Spatial points or locations do not have any properties of their own, so we still have the mystery of how BPs with no properties of their own can distinguish other entities. However, the beastie that proved so difficult for Aristotle comes charging to the rescue here. Once we realise that space is relational it becomes clear how the trick is pulled off. There is not in fact anything within the thing itself which gives it its unique identity (so the Bundle-theory is sort-of right). BP's are spatial locations, and spatial locations are really relationships with other things. So, the ultimate identity of something as a distinct individual, is its relationship to everything else, its 'place' in the world -- which we forgot about when we abstracted the thing from its context.