Life has not been kind to Captain Ahab, who is obsessed with destroying what he believes to be an evil force, the great white whale who cost him his leg. On the surface, one might look at Ahab's singular focus on anthromorphizing the whale and making it pay for its transgression as an indicator that Ahab as being mentally unstable, and dismiss him thus. However, upon closer examination, Melville has constructed a character that shares the archetypal features of a tragic hero, his fatal flaw being the thing that will be his undong, in this case, his lone battle to confront and exact revenge on a malicious being who is actually just a mammal acting on instinct.
Ahab is not unlike the hero of Cervantes's Don Quixote in terms of his ultimate motivation, which is a pure and sincere desire to do good, and both Ahab and Quixote share a predisposition to express themselves and their philosophical musings in flowery, romantic language. Melville's novel, however, is of a darker mood, and while the reader sees Ahab's honorable qualities, his delusions, and the arrogance with which he carries them out, is more ominous. In the tradition of the tragic hero, Ahab is ultimately defeated by his confidence in controlling a situation that is controlled only by Mother Nature.