He tricks him into believing his lies. Obviously, he hates Othello and wants to destroy him. This is one reason why critics suggest that he is the personification of evil. But just because a character wishes evil and does evil to other characters does not mean that he is any less of a human being. Human beings, Shakespeare shows, are capable of doing evil things. That is one lesson we can learn from Othello.
Another lesson we can learn from Othello is that, as Crouch states, it is impossible to label characters or persons. In other words, one should not try to dismiss Iago as pure Evil just to get around having to deal with him on a human level. By not labeling Iago as a personification of evil and instead looking at him like a human being, one is forced to face an unpleasant fact. That fact is that people can do evil to one another. That evil can be inside of all of us. To say that Iago is the personification of Evil is to say that the Evil is outside of us -- which is not what we learn from the play. The evil that is inside Iago spreads from him to others. Roderigo plays a part in his evil play. Othello begins to act less good and more evil. Cassio gets drunk and into a fight. We see that the evil can spread from person to person. It can be in any of us and in all of us. That is why it is important to see Iago more as a human being rather than as evil personified. When we look at him as a human, like ourselves, we can receive the lesson better. We can be more aware of evil in men and watch to avoid it.
Iago himself states that "I am not what I am," (1.1.65). Here he shows that he is full of lies. He is trying to deceive those around him. What he is on the outside is not what he is on the inside. This is the way many people often are. We fake our appearance so as not to seem worse than we really are. So is Iago the same way. He plans to pose as a friend of Othello ("In following him, I follow but myself") (1.1.58), in order to give him evil advice concerning the conduct of his new, innocent wife Desdemona. Iago is completely rational as he lays out his plot to Rodergio. He knows all along that he hates Othello -- and he knows all along that his ways are crooked -- yet, he rationalizes his ways because he does not believe in any higher way or in any such thing as virtue: "Virtue! A fig! 'tis in ourselves that we are thus or thus…It is merely a lust of the blood and a permission of the will" (1.3.322-340). According to Iago, all motivation comes from want or selfish pleasure. Iago believes in selfishness. Many human beings can be that way. It may be evil -- but it is also human. What others call honor or valor or virtue, Iago calls self-promotion. When he does not get his promotion, he decides to take his vengeance.
In conclusion, it would be unfitting to state that Iago is a mere two-dimensional personification of Evil. Iago is, after all, a man who shows many human characteristics. He makes jokes, he has a wife, he has a friend, and he shows envy. One even finds Iago to be attractive on a level. Of course, Iago is not to be trusted. He is the villain of the play -- but that does not mean that he is less of a human. As Rosenberg and Crouch state, by saying that Iago is a symbol evil, one must say that all the characters are symbols. The truth is that they are actual persons, not personifications of Good or Evil. People often have both good and evil in them. Iago just has more evil than good.
Crouch, J.H. "The Colorado Shakespeare Festival -- 1970." Shakespeare Quarterly vol.
21, no. 4 (1970), 465-467. Print.
Rosenberg, Marvin. "In Defense of Iago." Shakespeare Quarterly vol. 6, no. 2 (1955),