can also define Bartleby's life edict as a form of self-expression or even a form of self-preservation. 

It seems that Bartleby is intent upon protecting his own intellectual and physical freedom. After performing admirably on an array of tasks, Bartleby seemingly becomes uncooperative overnight. When asked to proofread some documents, Bartleby simply responds with a polite "I would prefer not to." This frustrates the narrator, because Bartleby's reply is surface courtesy without the expected submissive acquiescence. What's even stranger to the narrator is that Bartleby never appears to leave the office for dinner.

It looks like Bartleby's rebellion is both psychological and physical in nature. Meanwhile, the narrator is thoroughly frustrated with him. It is difficult to fire someone like Bartleby because he seems so helpless and child-like:

Poor fellow! thought I, he means no mischief; it is plain he intends no insolence; his aspect sufficiently evinces that his eccentricities are involuntary. He is useful to me. I can get along with him. If I turn him away, the chances are he will fall in with some less indulgent employer, and then he will be rudely treated, and perhaps driven forth miserably to starve.

The narrator tries to work with Bartleby, but to no avail. No matter what he asks Bartleby to do (whether to go to the Post Office or to call another employee into his office), Bartleby answers with his customary "I would prefer not to." Despite Bartleby's stubbornness, the narrator reluctantly admits that his employee is an excellent copier. He just refuses to do anything apart from the task he has been hired for. Eventually, he stops doing even that.

Perhaps, most ominously, Bartleby soon stops taking in nourishment; he engages in the ultimate hunger strike. Bartleby's resistance to corporate culture eventually kills him. Bartleby's actions go beyond anything advocated by passive resistance movements. In fact, he continues to stay in the narrator's office even after he has been dismissed from his position. Bartleby's "I would prefer not to make any change" is startling. However, it also draws attention to his obvious suffering.

He is seized by a mental and physical paralysis. Perhaps, Bartleby's actions highlight a very important fact: corporate culture is least forgiving to those who are by nature "prone to a pallid hopelessness..." In that sense, perhaps we can define Bartleby's life edict as a form of self-expression, his attitude a litmus test of his mental anguish.

Bartleby had been a subordinate clerk in the Dead Letter Office at Washington, from which he had been suddenly removed by a change in the administration. When I think over this rumor, I cannot adequately express the emotions which seize me. Dead letters! Does it not sound like dead men? Conceive a man by nature and misfortune prone to a pallid hopelessness, can any business seem more fitted to heighten it than that of continually handling these dead letters, and assorting them for the flames?

Oh my, there is ASTOUNDING significance in Bartleby's frequent quotation of "I would prefer not to" in that dear Bartleby is exemplifying the anti-Transcendentalist viewpoint of Melville.  In this way, Bartleby knocks order upside down through his continual, anti-Transcendentalist request.

Let's look at the progression into chaos due to upsetting the natural order.  At first, Bartleby seems to be an adequate scrivener.  He works hard until one day he refuses to copy one document by using his famous line ("I would prefer not to").  This escalates into Bartleby not "preferring" to do ANY of his work.  Further, Bartleby is now fully freeloading at the lawyer's office by living there full-time and eating only Ginger Nut's cakes and apples. 

My first emotions had been those of pure melancholy and sincerest pity; but just in proportion as the forlornness of Bartleby grew and grew to my imagination, did that same melancholy merge into fear, that pity into repulsion.

It is interesting here how the lawyer "begs" Bartleby to work or to leave.  Even this is an upset of who is in control.  (Melville, by the way, loves that upset.  Think of Moby Dick where the power of the novel is the white whale driven by brute instinct.)  This is a very anti-Transcendentalist idea.  In this way, Bartleby (and not his employer) is in complete control of the situation!  The lawyer even MOVES HIS BUSINESS to escape Bartleby's doings!  It is only the new owner who has the gumption to evict Bartleby who simply stays in the building continuing to frustrate the lawyer who offers to take him home with him.  Finally, the narrator leaves the city out of complete frustration. 

Bartleby defies a new order when he enters the city jail (the Tombs).  Because he is requested to eat, he replies with his usual, "I would prefer not to."  Now Bartleby is not just denying the hierarchical order (even with the lawyer still trying to help him), but the NATURAL order.  Organisms must all eat in order to live.  This doesn't matter due to anti-Transcendentalist ideals.  Due to the lack of food (in addition to the depressing conditions of the prison), Bartleby dies. 

Is this mental illness? Simple introversion?  Depression?  It doesn't really matter.  Mental illness IN ITSELF is a denial of the natural orders of the brain!  (An anti-Transcendentalist's paradise!  Think of the obsession of Captain Ahab!) Regardless, Melville ends with what eNotes calls the "pathetic universality" of the last line: “Ah, Bartleby! Ah, humanity!” There can be nothing more anti-Transcendentalist than the death of a human by defying the natural order of things.  Mental illness or not, in defying nature, Bartleby hastens death.