Silas, bewildered by the changes thirty years had brought over his native place, had stopped several persons in succession to ask them the name of this town, that he might be sure he was not under a mistake about it. (2.21.7)
In the thirty-one years since Silas left home, his town has become a huge manufacturing city—so big and so different that he's not even sure it's the same place. But is it? If something changes, is it still the same? (That's profound.) Aside from the warnings about industrialization, this passage raises questions about nature and substance. How much can something change before it's different?