Iago feels more competent because Casio is nothing more than "a great arithmetician", while he claims to be more worthy of this position which was indicated in the first solliquy when he suggested "I of of which his eyes had seen the proof in Rhodes, Cyprus and other places." At this point, the audience begins to wonder if this is the real reason why Iago decides to destroy Othello. He firmly believes that it was an injustice done to him by Moro when he did not receive the position of lieutenant he deserved