The suspension of disbelief—sometimes called the willing suspension of disbelief—was first discussed by Samuel Taylor Coleridge—in 1817. Right in the middle of the Regency, which, I suppose, matters not at all. But, of course, I noticed the date.
The suspension of disbelief has frequently been assumed to be the responsibility of the reader, who must make an effort to give the author the benefit of the doubt and enter into the world presented in a poem or work of fiction. But, the writer must not overburden the reader with challenges that make suspending disbelief too much of an effort for the enjoyment of the plot, characters, and setting. The genres of Science Fiction and Fantasy come to mind immediately when the suspension of disbelief is mentioned. But every genre, and even the most “realistic” literary fiction, must permit, if not encourage, the reader to become immersed in an imaginary world without being rudely awakened by an alarm inserted by the author.
In all writing, typos, grammatical, and spelling errors, serve as irritants that distract from the enjoyment of a story. I suspect that the average reader of historical fiction might be a bit more aware of such lapses than readers of some other genres. But that is just the beginning of the details that writers of historical fiction need to get right.
Obviously, historical facts must be accurate. Did the character’s father die at Trafalgar? Even if the date and location are not stated in the story, the writer had better know them, or other details of the narrative might not make sense. Are Pilgrims celebrating Christmas in your novel? Some readers might breeze through such a scene with no hesitation. But you can bet that some readers will close the book and never read another book you write. The intricacies of post-reformation English religious beliefs and practices might sound arcane, but knowledge of them is essential to any fictional portrayal of Colonial America.
In Through the Lookinglass, the White Queen tells Alice, “Why sometimes I’ve believed as many as six impossible things before breakfast.” Would that all my readers were so generous! But, one assumes, that even if the White Queen generously grants the writer six impossible things, a seventh could very well induce her to slam the book shut and toss it across the royal room. So I might ask you to believe that little green men with antennae have just landed on Earth, or that my heroine has red hair, but no freckles. Perhaps I have as many as five more unlikely assumptions to ask you to believe. But at some point, one more impossible thing will break the spell. The trick for the writer is knowing what that is.