Full Idea
A combinatorial ontology holds that existence is nothing more or less than completeness and consistency, or what is also called 'maximal consistency'.
Gist of Idea
Existence is completeness and consistency
Source
Dale Jacquette (Ontology [2002], Ch. 2)
Book Reference
Jacquette,Dale: 'Ontology' [Acumen 2002], p.62
A Reaction
You'll have to read Jacquette to understand this one! The claim is that existence is to be defined in terms of logic (and whatever is required for logic). I take this to be a bit Platonist (rather than conventionalist) about logic.