Armstrong argues that states of affairs are distinct things in ontology because they are more than the sum of their parts. If some particular "a" has a non-symmetric relation "R" to another particular "b", then "R (a, b)" differs from "R (b, a)". It may be the case that "R (a, b)" obtains in the world but "R (b, a)" does not. Without states of affairs instantiating the particulars and universals (including relations), we cannot account for the truth of the one case and the falsity of the other.