You could use the questioning process as a way of starting a discussion on the nature, and indeed existence of “truth”. Never to young to introduce your kids to good ‘ole philosophical debate!
Daughter – Daddy, does Father Christmas exist? Is he really flying all over the world on Christmas Eve delivering presents?
Daddy – Well, that’s an interesting couple of questions, first off just because something doesn’t fit in with our generally held understanding of how the world works, it doesn’t mean that it doesn’t exist. For example, if Santa was a quantum particle then my understanding of quantum physics (and I hasten to add it’s pretty limited!) means that there is the possibility he could be in all places globally over the course of one night! So, if we assume that out knowledge base is sufficiently limited then even asking the question seems a bit absurd.
Daughter – Whats a quantum?