Herman Melville's story of a most passive Bartleby is, indeed, ambiguous, but the ambiguity is well designed. Is Bartleby another side of the narrator, "the other end of [his] chambers, or is he a separate character? Because the narrator, the lawyer, is a person of almost sixty years who admits to being "filled with a profound conviction that the easiest way of life is the best," it becomes possible to consider that Bartleby is an alter-ego of the narrator with whom he "remonstrated." However, Bartleby simply stares blankly at the wall outside his window in a "dead-wall reverie," an act that symbolizes the stultifying effect of his previous job in the Dead Letter Office and his present job of transcribing the words of another.
Some critics perceive Bartleby as symbolic of the deadening effects of his position as a scrivener and, on a larger scale, capitalism. For, the attorney-narrator finds himself in a position in which he "would rather not." Imprisoned by the walls of his job as well as the walls of his life, Bartleby, the spirit of the narrator, who is trapped inside the walls of capitalism, languishes and dies, as it is, unable to interpret the significance of making money, if there is one.
Melville is fictionalizing the conflict between action and inaction. In the complicated, commercial, action-driven world of Bartleby and his firm, one's worth, in fact one's very identity hinges on the ability to make decisions, to act in a timely manner, to be an active participant in the day-to-day business of asserting one's will. By building an opposite character, Melville makes strikingly clear this invisible urge to decide, to live as though our decisions are important. Bartleby, because of his job as copier, has read all documents of the company, and has seen through the superficial decision-making mentality, and has chosen to no longer decide--"I prefer not to." It's a complex philosophical stance, a precursor to existential literature of the mid-20th century.