Hawthorne most likely uses the physician to represent the views of the most educated among Reverend Hooper's congregation. Because the physician is both educated and articulate, his reaction to Hooper's veil carries more weight with the reader than the reactions of less prominent people in the village. Being a man of science, the physician's initial reaction to the veil is "something must be amiss with Mr. Hooper's intellects," a natural response from a person who first looks for physical causes of unusual behavior but, as we later learn, way off the mark. And, more important, the physician's reaction to his wife's comment that Mr. Hooper might be afraid "to be alone with himself" allows Hawthorne to foreshadow the intense fear Reverend Hooper displays when he sees himself in a mirror. We know then that Hooper is indeed afraid to be alone.
Hawthorne's view of human nature is very complex but founded on a belief that human nature is essentially flawed to one degree or another. Many of Hawthorne's main characters--Young Goodman Brown, Reverend Hooper, Aylmer (in "The Birthmark")--display essentially self-destructive behaviors as a response to their perceived roles within their societies, and these destructive behaviors often destroy the lives of those around them.
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