Full Idea
A 'myth' or fiction for me is a true internal statement (a statement endorsed by the rules) whose external truth value is as may be, the point being that that truth value is from an internal standpoint quite irrelevant.
Gist of Idea
For me, fictions are internally true, without a significant internal or external truth-value
Source
Stephen Yablo (Does Ontology Rest on a Mistake? [1998], IX)
Book Reference
Yablo,Stephen: 'Things: Philosophical Papers vol. 2' [OUP 2010], p.129
A Reaction
This contrasts with Carnap, for whom talk of 'ghosts' is false in an internal thing-framework. Yablo seems here to say a statement can be true while having no truth value. Presumably he is relaxing the internal rules.