If Iago is reason, and Roderigo seeks reason, and Iago is the cause of all this destruction, then it should be said that the human need for reason (which crushes emotion) is what brings downfall. Logic is what has cut off Othello's motivation (heart). Iago is the personalization of human reason

Simply considering, helpless to his inner suspicions that rule him (Iago) ... It is all just our inner paranoia that causes conflict -- aka. our inner Iago