When an audience sits down to watch a film, or when someone starts to read your script, you are asking them to suspend their disbelief. This is obvious in fantasy genres, including horror films, science fiction, and stories set in imaginary times and places. But the same goes for the most grittily realistic current drama. No matter the genre, audiences must suspend their disbelief in order to enjoy the film. In realistic genres, this involves them getting so wrapped up in the story that they forget they are sitting in a dark room watching a projected image of actors saying lines written by someone, with lighting, background music, and artificial situations all added to enhance their experience. When you are writing a fantasy, they must do this as well as believe, temporarily, in the world you are creating.
The only way you will get your audience to suspend their disbelief enough to enjoy your story is to be consistent with the rules of the world you have created. Again, this goes for fantasy and realistic genres. It’s obviously true for fantasy worlds. We are all familiar with the standard rules for vampires-sunlight or a stake through the heart kills them, garlic and crosses scare them away, they can’t come in your house without you saying so. Because vampire lore is so familiar, any movie about vampires must abide by these rules, or explain when they break them. If the rules are broken, the story becomes inconsistent, unreliable, and draws attention to itself. If you’re creating a brand new fantasy world, such as the author of the Harry Potter books did, you need to establish rules and remain consistent to give your world credibility and create a sense of place for your audience. In Toy Story, the rules are subtly established early on. The toys remain motionless when the kids are around, but once they leave the toys spring to life, inhabiting a world of their own. We understand that one of the rules is that the humans don’t know the toys are animate, and the toys try to maintain this illusion. When they do break the rules, to scare Sid, it is explained and understood why they do this. Science fiction movies and television shows must do this well, and any new technology used must be explained and work consistently. When these rules are broken, they create holes in the story, and you’re left with questions that remind you that you are watching a poorly crafted film. Your disbelief comes back into play, no longer being suspended, and you stop enjoying the film. In The Time Traveler’s Wife, we see early on that Henry has no control over his traveling, that he always ends up naked when he arrives in the new time period, and that because of this affliction, he has learned to fight, to pick locks, and to steal and run away. This is established so that when we see him doing these things we understand why and feel that it is realistic and consistent with his character.
This concept is harder to understand in non-fantasy genres, but it is still important. Your characters must behave in ways that are consistent to their personalities, lifestyle, and background. If your story, for example, requires your hero to perform a perfectly executed ballroom dance routine in Act Three, it would seem out of place if we had never seen them dance or take a lesson before. If you show them practicing or dancing early on, we will accept that they do know how to dance and feel that it is believable when they start dancing in the climax. Realistic films also must abide by the laws of nature that govern the natural world. If everything in your film is supposed to be real, you can’t suddenly out of nowhere have your hero able to make himself disappear, or fly, without explaining how these superpowers came out of nowhere. You’ll notice in superhero films, such as Spiderman, when the hero first comes into their powers, they will spend scenes testing them, which establishes and shows us what they can and can’t do. This lays the groundwork for the rest of the film. We know early on that Spiderman can fly using his web material, that he is very strong and agile, but he doesn’t have, say, super healing powers like Wolverine. Wolverine can heal, is nearly indestructible, but he cannot fly. The characters behave within these rules, and if they fail to do so, we would immediately notice and dismiss the film as poorly written and inconsistent.