The real inhabitant of the bed, Mrs. Slipslop, perceives that Joseph thinks her bed is Fanny’s.  None too displeased at the prospects of enjoying the charms of Joseph, Slipslop prepares to affect the character of Fanny.  Both characters soon find out that they have mistaken each other’s identity when Beau leaps happily into bed with Mrs. Slipslop.  He, having no idea who she is, attempts to flee the bed.  Slipslop, however, upon discovering that her night visitor is not Joseph Andrews, switches her affectation of Fanny’s charms to affectation of Fanny’s chastity, shouting for help from an attempted rape.  Slapstick satire ensues, as the supposed damsel in distress manhandles and overpowers poor Beau.
The satiric narrative of colorful, pied, and ribald slapstick plays a carnavalic role in the narrative of Joseph Andrews.  This passage of mistaken identities illustrates the ridiculous in a variety of ways.  First, this narrative is a parody based on discovering the hilarity when one characters mistakes real virtue for affected virtue.  Also, coming immediately after two chapters that are charged with interior tension, this scene very physically, almost cathartically dissolves that emotional tension in laughter.  Ultimately, the ridiculous scenario introduces a different kind of mistaken identity: Parson Adams, the English Don Quixote.
When Beau climbs into Slipslop’s bed, Adams is meditating in his room.  Upon hearing a fair damsel in apparent need of help, Adams leaps straight towards the fray, too chivalrous to delay rescue even long enough to put on any clothes over his nightshirt. The parson chivalrously jumps into Mrs. Slipslop’s bed.  Mixing identities in the dark bedroom, Adams feels the soft skin and hears the effeminate voice of Beau, and concludes that that person must be the would-be-ravished.  He feels the hairy chin of Slipslop and concludes that that person must be the ravishing one.  Adams proceeds to do the manly, chivalrous deed of fighting Mrs. Slipslop.  The battered Beau escapes, while Adams and Slipslop engage in an epic dual.
Upon perceiving Slipslop’s mountainous breasts, Adams is forced to admit reality: he has been fighting violently with a woman, lying almost naked in her bed—not quite the chivalric ideal.  Even so, Adams’s false perception is not just ridiculous satire on Adams’s impracticality.  Fielding has throughout the novel ridiculed characters (such as Beau) who try to ravish ladies, so Fielding does mean to commend Adams’s intentions of chivalry.  In this scene, Fielding even portrays a degree of sympathy with the Slipslop, by showing that Adams’s peculiar quixotic identity is somehow ridiculous for being out of touch with reality. Slipslop’s chastity in this scene with Adams is not merely an object worthy of ridicule, because she actually was suffering from a physical attack from a man.  In other words, Adams perpetuates the attack on his chivalrous character in his attempt to fulfill his own chivalry.
Discovered identity works differently in this scene than in the scene with Beau and Slipslop.  Moving up from discovering two completely affected and ridiculous characters, Fielding has moved to a type of comic discovery of identity that acknowledges some degree of goodness in both characters.  If sympathy is meant for Adams’s chivalry (it is), then some degree of amiability for the characters of both Slipslop and Adams is required on the part of the reader.  The discovery that both the ridiculous character and the ideal character require some sort of amiable balance is, to repeat Paulson’s thesis, “the distinguishing feature of comedy” in the eighteenth century.
