What are Iago’s motivations in his actions toward Othello, Cassio, and Roderigo? What is his philosophy? How does his technique in handling...

 Samuel Taylor Coleridge's belief that all efforts to discover the impetus behind Iago's actions were 'the motive hunting of a motiveless malignity'. In other words, sometimes there is no complete explanation. There are many factors which MIGHT motivate Iago. He might be displeased at having been passed over for promotion by Cassio, who he dismisses as having 'mere prattle without practice. He might be inherently racist, as many Venetians were. Indeed, Iago seems to delight in shocking Brabantio with his statement that even now, having eloped with Desdamona,  'an old black ram is tupping [his] white ewe'. Iago might believe that Othello has been having an affair with his wife, Emilia, although he admits, 'I know not if it is true' but 'for mere suspicion' could use this information to his own advantage. His interest in Roderigo is entirely mercenary. This is seen over and over again when he tells the audience that 'now do I ever make my fool [Roderigo], my purse'. However, when Hannah Arendt, journalist at the Nuremburg trials talks of 'the banality of evil' to describe Eichmann's motivations, she could just as easily be speaking of Iago. The latter of course, even under threat of torture, has the last word, even  ironically, as he proclaims his silence, when he says 'Demand me nothing. What you know you know. From this time forth, I never will speak word.