Surgat (surgat) wrote in furry_thinkers,

Problem of Universals

Are there such things as properties, such as “redness,” “whiteness,” “mass,” or “electromagnetic charge?” If so, do multiple things share properties that determine what type of thing they are and what’s predicated of them, i.e. “X and Y are both red/red things because they share redness?”

I say there are properties, but things don’t share them.

Properties can explain why predicates are true of their subjects: water “freezes at 32 degrees Fahrenheit” because of its properties. Properties make it the kind of thing that it is, and do the kind of things it does. If on the other hand you deny the existence of properties (nominalism), you have to say that water freezes because of the kind of thing that it is, which leads to a dilemma. Does water freeze at 32 degrees Fahrenheit because water is of the type of things that freezes at 32 degrees Fahrenheit, or is water of the type of things that freezes at 32 degrees Fahrenheit because it freezes at 32 degrees Fahrenheit?

Denial of properties also leads to trouble with higher order types. For example, a nominalist would try to explain sentences like “red is a color” as meaning “red things are colored things,” but this isn’t an adequate translation: you wouldn’t translate other sentences this way. “Red things are extended things” doesn’t mean “red is an extension.”

How do you explain causation without properties of some sort, anyways?

As for whether or not properties are repeatable/shared by more than one thing (universals), tropes (properties as being particular) seem to have an advantage over universals in terms of simplicity.

With repeatable properties, you have to posit the existence of substances –things that “have attributes” and persists through changes in properties- as well as properties. If you try and say that particular, concrete objects are really just bundles of properties, you’re committed to believing in the Identity of Indiscernibles. That is, for any properties, for any Thing X, and for any Thing Y, if the properties of X are the properties of Y, X is Y. But it’s conceivable that there be two different things with the same properties (see The Identity of Indiscernibles, by Max Black).

Under a trope theory, you don’t have to posit the Identity of Indiscernibles, since two things never have the same properties. Properties aren’t repeatable or sharable. Thus you don’t seem to need two kinds of things, properties and substances, as with Realism. Because of this and the fact that tropes "do the same work as" universals, on account of Ockham's razor we should believe in just tropes.

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