Ahab- mad or evil?

James claims about Ahab: he is not a man of peculiar personality. It is the life that he lives that makes him what he becomes. In other words, there is not something essential in him that creates his totalitarianism, rather it is his isolated lifestyle that has led him to become the man he is. This isolation has detached him from humanity.

James goes on to say that although Ahab also benefits from material progress, industrial civilization is "destroying his life as a human being", causing him to live an "inhuman existence". Ahab's problem, says James, is representative of the problem of world civilization. For now, I am not sure that I quite understand if the deadly whale bite is a trigger or a cause for Ahab's evil. Until Ahab's "violent catastrophe", how is Ahab different than any other captain of a whale boat? Are they all easily susceptible to totalitarianism?

As James builds up Ahab's character as a prototype madman, he states that "men who are thinking like that…are being steadily prepared for desperate action". If a "violent catastrophe" descends upon them, "they are going to throw aside all the traditional restraints of civilization".  Meaning, when Ahab gets his leg bitten off, the totalitarian within him is unleashed. It seems to me like a few stages have been skipped here. How did we get from an extremely lonely captain to the monomaniacal man that he now is?  Does that mean that a violent catastrophe is liable to transform every modern man into a totalitarian?

All this renders James' comparison of Ahab to Hitler and other dictators problematic; Hitler didn't contrive the final solution after experiencing a violent catastrophe.  Saying that would be bordering on blasphemous. Rather, as James tells, the Nazis had a frightfully calculated plan; it didn't arise from a whim, or from chance events. Doesn't calling Nazis "mad" release them from responsibility for their actions? In the same sense, when we call Ahab "mad", aren't we letting him off the hook?  What are the real roots of Ahab's evil? And if I'm already on a question roll- if, like we saw in the previous lesson, the idea of the whale as a whale gets deflated, why does Moby Dick have to be a whale? This projection of hate seems so arbitrary. Obviously, we are dealing with the whaling business, and Ahab is wreaking vengeance on his whale attacker, but if a seagull (a somewhat slightly less ominous animal) would have poked his eye out instead, would we be reading about man's chase after bird? Is there a reason (besides the whale happening to be the animal that attacked him) that Ahab "piled upon the whale's white hump the sum of all the general rage"?