Othello is a tragedy because it tells the story of a noble, principled hero who makes a tragic error of judgment, leading to a devastating climax in which most of the characters end up either dead or seriously wounded. In assuming Iago operates according to the same rules of honor as he does, Othello cannot conceive that Iago might be lying to him about Desdemona. Othello’s fatal misunderstanding of Iago causes Othello to murder his wife, then kill himself once he realizes his error. Similarly, Othello misreads Desdemona: she gives him no reason to suspect her fidelity, but Othello ignores all indications of her loyalty once Iago suggests she’s cheating on him. Othello’s inability to distinguish between truth and falseness, and to conceive that not everyone acts according to the same principles he does leads to many innocent characters suffering before Iago’s villainy is revealed. Othello gains knowledge of his errors of judgment at the end of the play, but cannot reconcile the jealous, murderous person he’s become with his concept of himself as an honorable and moral person.
Shakespeare’s tragedies usually feature a protagonist who begins the play in harmony with his community. For example, King Lear opens with Lear in charge of his kingdom and enjoying all the privileges of his position. Macbeth starts with Macbeth as a promising general in line for promotion. Othello, on the other hand, begins the play alienated from his community. Unlike Iago and Desdemona, he is neither a Venetian nor a noble nor a civilian. As Iago points out, Othello is different from Desdemona in “clime, complexion, and degree” (III.iii). Furthermore, he has spent so much time in battle, he is unaccustomed to civic life: “Rude am I in my speech/ And little blessed with the soft phrase of peace” (I.ii) he says. In presenting a protagonist who begins the play as an outsider, Othello deviates from other Shakespearean tragedies, and provides potential reasons for Othello’s vulnerability to Iago’s manipulations. Othello’s uncertain social standing may incline him to disbelieve that Desdemona could actually love him, and to assume Iago’s stories about Desdemona’s infidelity are plausible.