How is Chapter 11 significant to the theme of the novel?

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...