The tone of this novel is always thoughtful, as Eliot's narrator recounts the emotional and social changes the protagonist undergoes. However, it's not always serious, as there are many points in the book where the narrative voice is amused, reflective, or forceful depending on what's being discussed. Much of the body of Silas Marner is made up of the narrator describing interactions in detail, and then returning to them to wryly observe things or give an additional moral context. The reader is given a sense that everyone and everything has a side that Eliot can either poke fun at, or invest with additional ethical and allegorical significance. The narrator in Silas Marner is smarter than the reader; they see everything from every angle, and suggest new readings and new nuances in events ranging from Silas's exile from Lantern Yard to Eppie's wedding in the Conclusion.
Within this variable, clever, and mobile voice, the tone of Silas Marner is often sentimental and sympathetic. The narrator lovingly recounts elements of Silas and Eppie's budding relationship and the beauty of the Northern English countryside. It's never cheesy—Eliot's style is too academic and self-aware for that—but it does betray a deep investment by the narrator in Silas's progress. Eliot's omniscient third-person narrator is uniquely observant and present in this book, often directly telling the reader how they should interpret the thoughts and choices of characters.
The religious elements of the novel are also reflected in the narrator's tone, as they seriously and formally guide the reader through the moral progress of the novel and of Silas Marner himself. The narrator's tone can move from humor and light social commentary to the solemn resonances of the Christian sermon within a sentence.