The three explanations attached to the scarlet letter that is revealed on Dimmesdale's breast help explore the scarlet letter as the governing symbol in this incredibly complex work of literature. The townspeople explain this scarlet letter by saying it is the result of the minister's own private scourge that started on the same day that Hester had to bear her own scarlet letter. Others state that it was a result of the dark magical arts of Chillingworth. Lastly, other people thought the scarlet letter was a result of "the ever active tooth of remorse, gnawing from the inmost heart outwardly" and finally resulting in judgement through the appearance of the scarlet letter on Dimmesdale's breast. Note what the narrator concludes about these different options:
The reader may choose among these theories. We have thrown all the light we could acquire upon the portent, and would gladly, now that it has done its office, erase its deep print out of our own brain, where long meditation has fixed it in very undesirable distinctness.
The narrator is effectively asking his audience to select their own interpretation of the scarlet letter and the strange events that resulted in the conclusion of the novel. The scarlet letter has been the most important symbol throughout the entire story and we are left to decide for ourselves what meaning, if any, can be taken away from it.