One idea that links the Salem Witch Trials of 1692 and "The Minister's Black Veil" is the notion that human beings fear the unknown. During the Salem Witch Trials, fear and hysteria spread like wildfire because people were so afraid of what they didn't understand. The people of the village became convinced that darkness had invaded their village, beginning with the Barbadian slave, Tituba, and they sought answers by trying to examine things that could not be seen. They very much feared what they could not see.
This same fear of what is not immediately visible is examined in the "The Minister's Black Veil" as well. Mr. Hooper begins to wear a veil that covers almost his entire face because he recognizes that he, like all human beings, possesses "secret sin," sin "which we hide from our nearest and dearest [...]." To admit one's own sinful nature would be to expose oneself completely to the world, and this is too frightening a prospect for us to bear. We fear what would happen if we revealed our true, sinful natures, and so we keep them hidden, thus isolating ourselves from our peers forever. Further, when his parishioners first see him, their lack of understanding about why he wears the veil creates fear within them as well. Simply because his face is no longer visible, they begin to doubt the man's motives and identity. One old woman says, "'He has changed himself into something awful, only by hiding his face!'" She cannot understand his action, and so she inherently fears it. This fear of the unknown links the history of the Salem Witch Trials and "The Minister's Black Veil."