Hawthorne deliberately leaves the most obvious question unanswered. Why does Mr. Hooper wear that black veil? Most people are afraid to ask the minister that question, perhaps because they are afraid he has some ugly scar or skin disease or eye affliction he wishes to conceal. The reader is drawn into the story by curiosity, hoping that sooner or later an explanation will be given by the narrator or by Hooper himself; but at the end of the story the question remains unanswered.
The only person who asks him directly why he insists on wearing the veil is Elizabeth, who felt she had a right to know his secret and to see his face because they were engaged to be married. But through the long scene in which they discussed the matter, the minister would not reveal the answer to that question. In two of his responses to her questions, the minister uses the word “if” three times.
"If it be a sign of mourning," replied Mr. Hooper, "I perhaps, like most other mortals, have sorrows dark enough to be typified by a black veil."
"If I hide my face for sorrow, there is cause enough . . . and if I cover it for secret sin, what mortal might not do the same?"
Obviously he has no intention of telling her the truth—assuming that he even knows the truth himself.
Nathaniel Hawthorne was an introverted, reclusive man. Proof is that when he graduated from Bowdoin College he spent more than twelve years in seclusion, devoting most of that time to writing. Since it is anybody’s guess as to why he created a character who wore a black veil throughout his life, a possible reason is that the Reverend Hooper, like Hawthorne, wanted to hide from the world. The veil was not intended to be a symbol or an admonition but a device to enable a hypersensitive man to appear in public when necessary yet to remain in hiding at the same time.
The idea for the story may have come to Hawthorne because he liked solitude and disliked the gossip and hypocrisy that were so much a part of life in a small town like Concord. A lot of his stories, including "Young Goodman Brown," show his poor opinion of people in general. In other words, Hooper may have been Hawthorne’s alter ego. Hawthorne himself would have liked to hide behind a veil. He chose the precarious career of a professional freelance writer because that was one way to earn a living without having to deal with people. One of Hawthorne's best stories is "Wakefield," and it too seems to suggest the secret desire or fantasy of the author to become virtually invisible--to be in the world but not part of the world.
But no one will ever know for sure why the minister wore that black veil, because Hawthorne wanted to leave his readers guessing.