Through the use of intimation, imagery and the theme of appearance vs. reality, the audience is convinced of Iago's success and Othello's deterioration.
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In this scene, the overarching theme of appearance vs. reality is an implied but a recurrent and significant one. Through Iago's character, Shakespeare analogizes materialistic/physical things to the main values explored in the play, successfully conveying to the audience the importance of both, but on a deeper level, how Iago has the ability both to hinder and manipulate them in his acts of "double knavery".
The handkerchief Othello gives to Desdemona, for example, embodies his love and trust for her, but more deeply his honour in her having accepted him, the "moor", the outcast. Thus, the loss of the handkerchief grew to become synonymous with the loss of its value, as is evident from Othello's change in narrative form, as it goes from a form of verse to prose.
In addition, Othello says, in line 35 on page 153, "Handkerchief––confessions––handkerchief! To confess and be hanged for this labour. First to be hanged and then to confess." in prose form, and Shakespeare's use of it accommodates Othello's use of chiasmus in his speech. Ironically, where chiasmus is used typically as a device to articulate balance or order within a text, the use of it in Othello marks precisely the opposite. Through this Shakespeare conveys Othello's convoluted state of mind – both mentally and emotionally, and therefore, Iago's success in his motivations.
Furthermore, in pairing both the physical and non-physical things, Iago is also able to draw contrasts between them, as, unlike Desdemona's handkerchief, her "honour is an essence that's not seen", thus insinuating her deceit to Othello. Likewise, the reverberation of Iago's use of the word 'poison' throughout several acts reflects his own duplicity, almost as if he chose to name it as such. Poison works slowly but effectively - the same way Iago's deception worked on Othello. However, on a deeper level, it also marks Iago's character development as his successes continually accelerate more of his schemes and plans, while at the same time weakening Othello.
However, it is the analogy between and a value and a sensual physical action, in an "unauthorized kiss" in line 3, that epitomizes and conclusively portrays Iago's complete manipulation of Othello, that by combining values of reputation and authority with love and emotion, Othello's weaknesses are used in Iago's power, leaving Othello to seemingly self-destruct.
In conclusion, it is Shakespeare's use of language and his successful implicit portrayal of themes through characters that allows his audience to unwrap themselves not only the true nature of the relationships between the characters, but also the complementing and contrasting values and ideals that inevitably exist amongst them.
