What are the two symbolic images of good and evil that battle over dimmesdales soul?
Old Roger Chillingworth becomes a symbol of the evil that torments Dimmesdale all through the book. As Hester's wronged husband, he sets himself up as a kind of avenging figure. He becomes the outward symbol of Dimmesdale's agonized conscience. Chillingworth has been cheated by Dimmesdale and Hester but he is not a very sympathetic character in himself, and becomes even more warped in the sense of his own grievance. He becomes nothing less than malevolent.
Pearl might be regarded as a symbol of good in relation to Dimmesdale. It is true that she is the result of Dimmesdale's adulterous affair but also Dimmesdale and Hester do truly love each other; there is genuine human warmth between them, and this can also act as a force for good. Pearl is also part of this, and at the end when she and her father meet openly for the first and only time, there is a sense of the redemptive power of natural human love.