Full Idea
Free logic is especially designed to help regiment our reasoning about fictional objects, or nonexistent objects of some sort.
Gist of Idea
Free logic was developed for fictional or non-existent objects
Source
Michèle Friend (Introducing the Philosophy of Mathematics [2007], 3.7)
Book Reference
Friend,Michèle: 'Introducing the Philosophy of Mathematics' [Acumen 2007], p.77
A Reaction
This makes it sound marginal, but I wonder whether existential commitment shouldn't be eliminated from all logic. Why do fictional objects need a different logic? What logic should we use for Robin Hood, if we aren't sure whether or not he is real?