Chapter XI of The Scarlet Letter is significant to the theme of the psychological effects of sin in two ways:
1. In the paradox of Dimmesdale's futile attempts at public confession, he increases his guilt. For, the more he asserts his own sinfulness, the more the townspeople perceive him as a holy man. Fully aware that his confessions are misunderstood, Dimmesdale, in his weakness,takes conscious advantage of this misunderstanding:
The minister well knew--subtle, but remorseful hypocrite that he was!--the light in which his vague confession would be viewed."
Here Hawthorne seems to wish his readers' sympathy for Dimmesdale does not blind them to the fact that the minister is, in fact, a true sinner.
2. Chillingworth, on the other hand, seems even more evil and blacker than ever as, in Chapter X, after having put aside the sleeping minister's garment, he has "violated the secrets of the human heart" and now becomes a "chief actor," controlling the agony of Dimmesdale. However, Hawthorne again establishes a balance for the readers and prevents them from a perception of the physician as pure evil. For, he describes Chillingworth as a
poor, forlorn creature...more wretched than his victim...
Chapter 11 of The Scarlet Letter contains one of the most revealing (pardon the pun) moments of the novel. This is a chapter which really only involves two characters, Dimmesdaleand Chillingworth. The physician has been pretty straightforward about his belief that what is causing Dimmesdale's physical ailments isa spiritual matter--that the inner turmoil of the soul is showing itself in his body. This is not what Dimmesdale wants to hear, and the two have a rift. Dimmesdale later returns and asks forgiveness, and all is well between them once again.
While Arthur is resting, Roger walks in to find him sleeping much more soundly than usual. He takes this opportunity to do what he has been anxious to do--he opens Arthur's shirt. Then he dances in a way that would, if anyone had been watching, have looked like what Satan must look like when he knows he has stolen a soul from heaven. We aren't clear about exactly what he saw, of course, but it was some physical sign--presumably an A of some sort--which confirms Roger's suspicions. Arthur is the father of Pearl and lover of Hester.