Silas is in no way a heroic character. He is not notably intelligent or courageous or unselfish. He is a product of Eliot's desire to arouse sympathy for ordinary imperfect humanity going about its day-to-day business.
Silas changes greatly during the course of the book, yet part of him always remains "the same Silas Marner who had once loved his fellow with tender love and trusted in an unseen goodness." That original love and trust seemed crushed by the evils which befall him, but they return with even greater strength, and it seems natural that they should do so. The changes in Silas' character are never arbitrary. They have roots; they develop naturally from his past. The betrayal by William Dane costs Silas his faith in men, and the betrayal of the drawing of the lots takes his faith in a just God. The second robbery sets in place of the just God a vision of a "cruel power." Yet because he does believe in a power, Silas is able to believe that Eppie is sent for his salvation, and through Eppie's influence he finds new faith in the goodness of other men.
The unchanging part of Silas' character is that which requires some prop on which he can lean, something to support his courage to face life. When he loses his religion, he turns to his work, and then to his gold. When his gold is gone, he finds a better support in a child, which leads ultimately to his faith in his fellow men and in his own strength.
Silas is always honest, both with himself and with others. He is unable to question the rightness of church doctrine, and he will not easily believe that William would betray him. Later he cannot force himself to imagine anything suspicious about the strange peddler even when he wishes to believe that the man might have been the thief. But while he retains some good qualities, he loses his sympathy for men, and then all his affections are in danger of withering away. He becomes almost dead to the world. But when he appears in the final pages as a man with new faith, he has not been merely restored to his original position. He has gained maturity and inner strength. He has the courage to give up his daughter, his treasure, for her good. His faith is not based on unquestioned doctrine; rather, it survives in spite of doubts. His is no overwhelming triumph, but a believable, human one.