Further support for the theory that Iago's malignity is motiveless is the fact that Iago mentions many motives casually and often only once. Shakespeare took his source for Othello from a plot in Cinthio's collection of tales, "Hecatonnmithic". The Ensign of Shakespeare's source is motivated solely by his hatred of Disdemona, arising from his thwarted lust. This motive is mentioned by Iago only once, and in a much different context. At the end of Act II sc. I, Iago says of Desdemona, "Now I do love her too; not out of absolute lust….. but partly led to diet my revenge". It is interesting that unlike the source, Shakespeare chooses to make his Ensign's (Iago's) love for Desdemona serve as a catalyst for destroying Othello, rather than Desdemona herself. Also, this love for Desdemona is mentioned only once and is one of a number of motives mentioned by Iago throughout the play.
In his first soliloquy, Iago tells us that he "Hate(s) the Moor", but offers no reason for doing so. Even the suspicion that Othello is "thought abroad" to have seduced Emelia is mentioned more as an embellishment of his hatred rather than a source of it. Later, Iago also states that he "fears Cassio with his nightcap too", but ultimately his reasons for having the lieutenant killed are stated as "He hath a daily beauty in his life/That makes me ugly". Thus, Coleridge could well be justified in stating that Iago's malignity is motiveless.
However, there are other theories behind Iago's choice of actions in "Othello". In the first scene he tells Roderigo that he hates Othello for choosing Cassio rather than himself as his lieutenant. This would surely provide the justification for Iago's declaration that he "Hate(s) the Moor" in the beginning of his first soliloquy. Thus, any other motives mentioned by Iago later (he introduces elements of class-hatred, race-hatred and sexual suspicion) would be no more than embroidery of his main purpose. And indeed it is this theory of professional revenge that is endorsed by the critic Kenneth McLeish.
This theory hinges on the fact that despite years of loyal and excellent service (he appears to have no history of wrongdoing or transgression, ergo "honest Iago"), he has been passed over in favour of "(a man) that never set a squadron on the field, nor the division of a battle knows". It is for this reason alone that Iago vows revenge against Othello and Cassio. Thus, his motives and methods are manifest and practical - he retains the same purpose from start to finish and therefore adopts the same approach throughout, manipulating people and events to provide opportunities to fulfil his goal.
It could be argued that Iago's methods are simple because he is simple; just as Othello's personality depends on confidence in his own honour, so Iago's involves absolute trust in his manipulative powers. Thus, when things go wrong and the truth is discovered he collapses exactly like Othello into psychological panic and overt and disastrous action. And so this theory of Iago's motivation could be reinforced by proposing that Shakespeare deliberately created Iago as simple in order to craft a dramatic, tragic finale to the play.
Yet there are problems that arise when questioning the validity of this theory. To accept Iago as a simple-minded deviant would be to reduce those he manipulates to incredulous fools. This would of course be the undoing of the tragedy - nobody could pity Desdemona or Othello if they fell prey to an obvious villain. Shakespeare was obviously obsessed with Iago - he gave him more lines than any other character in his works. In Iago, he created a villain whose evil and treachery lie not in his motives, but rather in the lack thereof; by pledging himself to evil Iago becomes the "demi-devil" Othello speaks of in the last scene, yet by the endless quest for source or motive, Shakespeare makes his villain all the more sinister to the audience - he infused this devil with real human emotions.
Shakespeare knew that the love of power and mischief is common to man, and he instilled it in Iago. To that he added more factors to further darken his character. Iago has no respect for human decency or human life - when Desdemona becomes a victim he shows no sign of remorse. He mocks Othello's trusting nature "And will as tenderly be led through the nose as asses are". He hates romantic love, deeming it a weakness - "Ere I would say, I would drown myself for the love of a guinea-hen, I would change my humanity with a baboon". He is loyal only to himself and, indeed, he is proud of it “were I the Moor, I would not be Iago, in following him I follow but myself. Heaven is my judge, not I for love and duty, but seeming so for my peculiar end”. Not only is Iago a notorious liar and hypocrite, he also succeeds in fooling everybody. He is made even more menacing due to the fact that his insight into the behaviour of others is practically perfect – he can adapt to manipulate any person.
In Iago, Shakespeare not only created an inspired plot device, but a vessel in which to put across his key themes of the play. He was fascinated with appearance and reality – the inability to judge truth from lies. Iago highlights this in not only the way he manipulates his victims; he also serves as a catalyst for the theme to emerge in other characters. Thanks to Iago, Othello feels Cassio, a man whom he trusts and who appears loyal, has deceived him. Shakespeare dramatises the problem of judging honesty from dishonesty by showing the consequences of trusting someone whose mask of integrity is unfailing almost to the very last.
Shakespeare uses Iago to address society’s treatment of the outsider. It is unclear whether Iago uses race-hatred as a direct motive – whilst he casually introduces race as an aspect of his abhorrence, he never mentions it in soliloquy. Nonetheless, he uses it to stir up antipathy to Othello in other characters, for example Brobantio and Roderigo. Later productions of Othello sat quite comfortably in the context of 20th century apartheid, demonstrating how easily race could translate to a definite motive, given Iago’s language and the play’s appropriate environment. Regardless of this, what is clear is the way Iago exploits Othello’s awareness that as a man of another race and creed, much of the conflict he faces is due to the reigning opinion that he doesn’t quite belong. Othello’s sensitivity to the issue becomes clear when Iago uses it as proof that Desdemona couldn’t be faithful to a man so foreign – such a match is “unnatural”. Othello’s self-confidence is easily eroded by Iago’s ability to convince him that he is inferior to the men of Venice. Shakespeare dramatises through Iago’s treatment of Othello the tragedy of a man whose insecurities about his background, fed by public opinion, weaken his defences and allow his worst instincts to take over.
At the end of the play Iago is perfectly willing to confess what he has done, but he refuses to answer Othello’s question “Why he hath thus ensnared my soul and body?”. It is possible that Iago can answer the question; perhaps Shakespeare kept Iago’s motives ambiguous to the last so as to raise a broader question as to the nature of man, or so as to immortalise Iago’s enigmatic character. An alternative reason for his obstinate silence is that he will reveal neither his dedication to evil nor, more importantly, his jealousy.
From the very nature of Iago’s role, he cannot reveal his genuine feelings except in soliloquy. At the end of Act I the soliloquy acts more as an aside which throws a retrospective light on his conversation with Roderigo. It emerges that his hatred towards Othello is not anger at being passed over for promotion – this was concocted simply to assure his dupe of his hatred for the Moor. Yet why could Iago, a man who shows himself to be proud of his hypocrisy, indecency and dedication to evil not simply admit that he hates Othello for the sake of it? Perhaps it is because his real reason for his hatred is jealousy, aggravated further by the intolerable idea of being cuckolded.
In his first soliloquy, Iago reveals his suspicion that he has been cuckolded – “I hate the Moor, and it is thought abroad that ‘twixt my sheets he’s done my office. I know not if’t be true but I, for mere suspicion in that kind, will do as if for surety”. Bernard Spivach stresses the significance of the line beginning “and it is thought…” as “The seam between the drama of allegory and the drama of nature, with the kind of motivation proper to each”. Thus, Iago is invested not only with the malignity of a stage devil, but also with psychological motives for hating Othello – jealousy.
In Act IV, Emelia says “Some such squire he was that turned your with the seamy side without and made you to suspect me with the Moor”. By including this Shakespeare confirms that Iago’s suspicions were not invented on the spur of the moment to justify his villainy.
Later, when Cassio kisses Emelia, Iago’s aside suggests that he is not merely pretending that Cassio and Desdemona are in love with each other. In the soliloquy that follows on, he reiterates his suspicions of Othello and his wife, describing how the “thought whereof doth, like a poisonous mineral, gnaw in my innards” and how “nothing can, or shall content my soul till I am evened with him, wife for wife”. Here is clear evidence that Iago’s jealousy is not a pretence but a raging torment – the strong imagery is convincing in its vividness. Also, Iago proclaims his love for Desdemona and states “I fear Cassio with my nightcap too”.
And thus, through reinforcements such as his vivid portrayals of jealousy in Act II Sc III, (“the green eyed monster which doth mock the meat it feeds on”), we can come to another possible motive for Iago’s actions. He seems to have a pathological jealousy of his wife, a suspicion of every man with whom she is associated and a jealous love of Desdemona. In this, Shakespeare has managed to combine the malignity of the villain’s character with jealousy and envy to form the springs of Iago’s conduct. These motives all spring from the same attitude to life – the self-love of which Iago boasts to Roderigo.
Regardless of what motive we accept for Iago’s behaviour, I contend that this villain was created by Shakespeare to explore the concept of self-love and the dangers it can bring. Whether it be an innate sense of evil, fuelled by “a keen sense of intellectual superiority”; ideas of professional revenge triggered by the proud “I know my price, I am worth no worse a place”; or an ardent sense of jealousy, all of Iago’s behaviour is backed by an air of egotism and conceit. Perhaps Iago is Shakespeare’s warning against the sin of vanity and envy, that which Francis Bacon described as “the vilest affection and the most depraves; for which cause, it is the proper attribute of the Devil”.
Since the play was first written, critics have worked to assign psychological motivation and grounding to the conundrum that is Iago. Yet perhaps the most satisfying conclusion that can be drawn is in the ambiguity and elusiveness of the character, and the questions that these in themselves raise about the nature of evil, of sins, and of the nature of mankind. For as Coleridge said, “How many among our modern critics have attributed to the profound Author this, the appropriate inconsistency of the character itself!”