Indeed, certain of the most authentic historians of those parts, who have been careful in collecting and collating the floating facts concerning this spectre, allege that the body of the trooper having been buried in the church-yard, the ghost rides forth to the scene of battle in nightly quest of his head […] (1.4)
What are historians doing collecting "facts" about ghosts? Shouldn't they be writing about wars and economic policy in a dark room somewhere? Who gets to decide what history is, anyway?
However wide awake they may have been before they entered that sleepy region, they are sure, in a little time, to inhale the witching influence of the air, and begin to grow imaginative—to dream dreams, and see apparitions. (1.6)
Do you think Irving is trying to drop us a hint here with that word "imaginative"? As in, it's in their (and our!) imaginations?
There was a contagion in the very air that blew from that haunted region; it breathed forth an atmosphere of dreams and fancies infecting all the land. (1.52)
Is superstition a disease? If so, Ichabod needs to get a cure—and quick.
An inquiry was set on foot, and after diligent investigation they came upon his traces.[…] [O]n the bank of a broad part of the brook, where the water ran deep and black, was found the hat of the unfortunate Ichabod, and close beside it a shattered pumpkin. (1.69)
You know what they say: you see what you want to see. Apparently this "diligent investigation" didn't want to see a shattered pumpkin as evidence that there is no Headless Horseman.
It is true, an old farmer, who had been down to New York on a visit several years after, and from whom this account of the ghostly adventure was received, brought home the intelligence that Ichabod Crane was still alive; […] and finally had been made a justice of the Ten Pound Court. (1.72)
No one believes this guy. They think he's talking crazy talk. But what makes him so much crazier than Team Headless Horseman?
The old country wives, however, who are the best judges of these matters, maintain to this day that Ichabod was spirited away by supernatural means; and it is a favorite story often told about the neighborhood round the winter evening fire. (1.73)
Why do the old country wives get to be "the best judges of these matters"? We want that title. Dibs! Okay, now that we've claimed it, we declare that bacon is good for you.
"Faith, sir," replied the story-teller, "as to that matter, I don't believe one-half of it myself." (2.7)
If the storyteller doesn't believe his story is true, can it be true? How important is the narrator to the story?