|Overview of the Main Views on Universals and Particulars|
In my view, the "default theory" is realism. That is, there certainly are individual things and properties of those things. The most obvious position to take is that the individual things are particulars, their properties are universals, and both are equally fundamental. If you reject the existence of universals, you need to find an alternative account of properties; if you reject the existence of particulars, you need to find an alternative account of individual things.
So arguments for realism tend to be arguments against the alternative views, and in particular, arguments that the ways the other views try to define or account for individual things and properties don't work.
|universals are real and fundamental||universals are not fundamental
(or not real)
|Particulars are real
|Particulars are not
fundamental (or not real)
|bundle theory||trope theory|
(Note that Russell is not only a bundle theorist but also a phenomenalist: he not only wants to define particulars as bundles of universals; he also wants to define physical things in terms of experiential things. As if the project wasn't already hard enough!)
|The Identity of Indiscernibles|
The Identity of Indiscernibles is one of two principles about identity associated with Leibniz. The less controversial principle is the similar-sounding Indiscernibility of Identicals, which simply says that if x and y are identical (that is, are the same thing), then x has every property y has and vice versa.
The Identity of Indiscernibles is the converse of this: the view that, if x and y have all the same properties, then they are identical.
One issue that makes a difference here is exactly what we mean by a "property." If being identical with Curtis Brown counts as a property, then clearly it is a property nothing but Curtis Brown can have, and so the Identity of Indiscernibles becomes trivially true. (Well, it could still be important: the Indiscernibility of Identicals is an important truth even though it is similarly trivial.) Similar points arise for the "property" of being different from Curtis Brown.
But suppose we restrict properties to those that don't depend on particulars. Then the Identity of Indiscernibles becomes a more interesting doctrine. It may be an empirical truth, but it doesn't seem to be a necessary truth. Consider Black's example of the two exactly similar spheres. Doesn't each of the spheres have all the properties the other one has? They have all the same intrinsic properties (as long as we are not counting haecceities as intrinsic properties). And each also seems to have all the relations to the other that the other has to it. But they are the only two things in the universe, so there is no third thing for them to have different relations to.
The one sticking point may be spatial properties. The spheres occupy different locations. But it seems that this can only distinguish them if locations are themselves particulars. Then At(x, l) is a relation between an object and a location. But we agreed not to count relations to particulars as properties, so relations to particular locations would seem to be ruled out as well. The only spatial properties that will be legitimate are relational properties, e.g. being 50 meters from a steel sphere. And the two spheres have all the same properties of this sort.
[Unless they can be distinguished by their modal properties: there could be an object further from a than from b.
|The "Bundle Theory" of Particulars|
The Bundle Theory says that particulars can be "reduced" to universals. Ultimately all that exists is universals; when we talk about particulars, we are really talking about universals.
One version of this view is the idea that a particular is a set of universals. van Cleve offers six objections to this view, of which the last three also apply to some of the more sophisticated versions of the view.
The sixth objection is that if the bundle theory were true, then the identity of indiscernibles would be a necessary truth. As we've seen above, it doesn't in fact seem to be a necessary truth. So the bundle theory must be false.
|Summary of the Argument Against the Bundle Theory|
1. If the bundle theory is correct, then the identity of indiscernibles is a necessary truth.
2. If the identity of indiscernibles is a necessary truth, then there cannot be two distinct objects with exactly the same properties.
3. The example of the two spheres shows that there could be two distinct objects with exactly the same properties.
4. The bundle theory is not correct.