Returning to ch. 5, the narrator defines a novel as "only some work in which the greatest powers of the mind are displayed, in which the most thorough rough knowledge of human nature, the happiest delineation of its varieties, the liveliest effusions of wit and humor are conveyed to the world in the best chosen language."

One of the great things about novels is that they can explore human nature – just as the best sci-fi/fantasy novels of today often explore what it means to be human by setting themselves in an alien environment, the best Gothic novels set their characters in outlandish circumstances, then invite the reader to observe how the setting brings out the best or worst in them.

Hauntings, giant helmets, magic mirrors & branches, etc. may not exist in Catherine and Henry's England, but the same cruelty, greed, and selfishness which inspired them are present, just in different, socially acceptable forms. Wolves lurking in sheep's clothing, if you will. I think Catherine's observations and intuition picked up on General Tilney's character, but since she hadn't had any other real-life experience with people like him, she assessed his character based on the only other world she knew outside of her own – the Gothic novel.

Perhaps the best sort of novel reader can discern which parts of a character are the sensational, overblown details and recognize the core of human nature inside – then apply that core to "reading" (understanding) people in real life. Does that make any sense?