How do the various types of deception in Twelfth Night have significance in the play?
Although it has elements of Elizabethan romantic comedy--separated twins, mistaken identity, gender-crossing disguise--Shakespeare's Twelfth Night contains too much farce to be classified as a romantic comedy. Rather, with its theme of "the madness of love," Twelfth Night breaks from the conventional formula and is, as critic Harold Bloom writes, a
seriocomic rivalry with Ben Johnson, whose comedy of errors is being satirized throughout, a comedy based upon the two humors choler and blood.
Shakespeare ridicules these "mechanical operations of the spirit" with his wise fool Feste and Orsino, whose agreeable erotic lunancy and "sublime male fatuity" set the tone of the play:
There is no woman's sides(100)
Can bide the beating of so strong a passion
As love doth give my heart; no woman's heart
So big, to hold so much; they lack retention....
But mine is all as hungry as the sea,
And can digest as much: make no compare
Between that love a woman can bear me
And that I owe Olivia (2.4.100-110)
Further, this comic rivalry with Johnson results in Shakespeare's ambiguity of revels as there are deceptions and disguises and a malicious practical joke. Without much forethought, a shipwrecked Viola hears that the prince is a bachelor and decides to supplant the lady he courts. Then, Sir Toby Belch deceives Sir Andrew Aguecheek into believing that Olivia is interested in him in order to maintain his funding for drink; later, a malicious Maria and pompous Sir Toby Belch dupe Malvolio into believing Olivia is in love with him, convincing him to wear ridiculous clothing and act strangely in order to please Olivia. When he recites passages from the falsified letter and acts so strangely, Olivia believes he has gone insane and Malvolio is cruelly locked into a dark closet. Maria then convinces Feste to pose as a priest and question Malvolio, who begs him to believe that he is not insane, but Feste leaves him so confined.
Sir Toby Belch's and Maria's practical joke is maliciously gratuitous, merely satisfying their sadistic satisfaction while Viola's is one made as a means of survival. Nevertheless, all the deceptions of the play are damaging and cannot merely be attributed to mechanical cholers as Johnson would have his audiences believe.