And if the many sayings of the wise
Teach of submission I will not submit
But with a spirit all unreconciled
Flash an unquenched defiance to the stars.
Saranac Lake, 1913
What's up with the epigraph?
Actually, everything—everything is up with the epigraph. Adelaide Crapsey was an American poet who grew up in Rochester, New York, and wrote during the turn of the century. So there's the connection of place and time, along with love of words, between Adelaide and Mattie. Plus, the two writers (even though one is fictionalized) share a common indomitable spirit.
Of greater importance are the words of the poem, though. There are a couple ways to get at this epigraph. One is to focus on the tenacity of spirit and the rebellion of the speaker, and to relate it to the living characters in the novel. Despite the words of the wise, submission isn't in the cards for the speaker, and this rebellion against the status quo is really what makes Mattie—and Miss Wilcox, and Weaver—shine.
The true conflict in the novel is when these characters' defiant spirits are almost quenched by innumerable odds: Miss Wilcox by her domineering husband, Weaver by socially sanctioned racism, and Mattie by pressures of womanhood.
But another way to get at the poem is to read it in the context of the full poem, which is entitled "To the Dead in the Graveyard Underneath My Window." It is no coincidence that Donnelly chose an excerpt from a poem about death and ghosts to preface a novel in which Mattie's mother and Grace Brown haunt our intrepid heroine.
In the full poem, the speaker castigates the dead in their graves for accepting their fate without rebellion. And this, too, relates to Mattie's two futures: In one, she could accept her role as a woman in the Eagle Bay community without a fight or fuss, while in another, she could "not submit but… flash an unquenched defiance." We're glad that she chooses the second path.