Blackpool himself is a further experiment in the direction of the fully achieved emblematicism of A Tale of Two Cities. In other words, he stands for a situation, a class, a predicament, without having to exist for us in quite the same way as Louisa or Sissy exist for us. We must avoid any temptation to condemn him as unreal, and recognize a perfectly valid literary mode. Dickens is doing something difficult and unprecedented here; he is creating a character real by the standards of Victorian realism, but capable of functioning as a symbolic, almost an abstract term in an argument.
Geoffrey Thurley, The Dickens Myth, 1976
There are so many things that Dickens could have done with Stephen. More could have been made of the mine-shaft down which he falls: it ought to have been fenced in after it had been finished with, just as, when in use, its firedamp and propensity towards explosion could have been countered with protective devices: but at no point does Dickens erect it into a social indictment. More could have been made of Stephen's scanty and conditions of labour at the mill. It is significant that never once in this industrial novel does Dickens show us the day to day life of men in a factory. It would take more than a visit to Preston or Hanley to dramatize this in any depth of detail; yet some such undertaking ought to have been at the heart of the book. Stephen, in fact, is not dramatized as archetypal working man so much as a personification of a victim; not a social victim, either, but the victim of a broken-down marriage.
Philip Hobsbaum, A Reader's Guide to Charles Dickens, 1972