 In the previous sections we have seen that states of affairs can only play important explanatory roles if the necessarily co-obtaining states of affairs are distinct. This gives us a reason to reject Chisholm’s (1976: 118) thesis that necessarily co-obtaining states of affairs are identical. At the same time it puts weight on the characterization of states of affairs as “involving” objects and properties or as composed out of objects and properties. It seems intuitively plausible that the state of affairs Socrates’s being wise involves Socrates and the property of being wise. But in what way do states of affairs involve particulars and properties?