Full Idea
According to Terence Parsons, there is an object corresponding to every set of properties. To some of those sets of properties there corresponds an object that exists, and to others there corresponds an object that does not exist (a nonexistent object).
Gist of Idea
There is an object for every set of properties (some of which exist, and others don't)
Source
report of Terence Parsons (Nonexistent Objects [1980]) by Sarah Sawyer - Empty Names 5
Book Reference
'Routledge Companion to Phil of Language', ed/tr. Russell/Graff Faria [Routledge 2015], p.160
A Reaction
This I take to be the main source of the modern revival of Meinong's notorious view of objects (attacked by Russell). I always find the thought 'a round square is square' to be true, and in need of a truthmaker. But must a round square be non-triangular?