How likely is it that Gandalf may be real? He can exist if we occasionally read horoscopes, practice yoga, or wear amulets.

It was Aristotle who first warned young writers against littering their poems with supernatural occurrences. But at the same time, he knew that they could appeal to readers. Thus, he established some rules and showed what writers could do to make readers believe in such unreal characters.

The very first writer to succeed in creating unreliable yet highly plausible characters was Samuel Taylor Coleridge. The next example of success in this area was Walt Disney. Disney was able to create animations full of supernatural beings that we took for granted. Characters in his animations were ranked as highly probable to exist because their features or behaviours relate to reality. For example, he situated his unreal heroes in the natural world or gave them traits that exist in biology. From that point on, we can rank them on a believability scale, as if they were real.

Recently, there have been many studies on the linkage between our reasoning about supernatural powers and the real world. By ranking some magical powers on a believability scale, we can deduce how people perceive reality. Some magical powers, for example, violate too many laws of physics; others do not correlate with biology. The less the powers violate major laws of physics, the more believable they are.

All such rankings seem extraordinary, yet our whole lives are magical.