Arbitrary Skepticism

Real skepticism entails requiring evidence of good quality before believing something is true. Arbitrary Skepticism is the tendency of characters who deal with the strange and bizarre on a daily basis to dismiss anything "strange" off-hand rather than consider that, in light of everything else they've seen and experienced, a "fantastic" explanation really isn't that far-fetched.

Sometimes it makes sense — after all, just because aliens exist, it doesn't follow that something unrelated does as well - but the viewer is often left wondering how a character who has seen ghosts and vampires can feel so comfortable in immediately dismissing the possibility of, say, zombies. If the character has a plausible explanation of why zombies can't exist, it's not Arbitrary Skepticism, if they came to their conclusion through research and thought.

Sometimes this is used to define the extent of the fantasy of the world: for example, letting the viewer know that in this Fantasy Kitchen Sink, there are no vampires or ghosts, even if there are unicorns. Sometimes characters will discuss this, comparing someone's cynicism about talking bats to their fighting dragons last week.