Act Four, Scene One
Sir Politic and Peregrine enter as Sir Politic is giving instructions on how to be a gentleman traveler. He says that one must be serious in dress and discreet in conversation. He says that a gentleman must never tell the truth because strangers will thereby take advantage of him. He says to know the proper way to handle utensils and to be interested abstractly in religion, but not to take part in it. He claims that fourteen months ago, when he first arrived in Venice, people took him for a native. Sir Politic then elaborates on some "projects," or get-rich-quick schemes, which he has come up with. First, he talks of "serv[ing] the state / Of Venice with red herrings for three years" (4.1.50-1). Second, he describes how the danger of tinder-boxes could be controlled by regulating their size and their use at home. Third, he claims that, using onions and bellows, the plague could be discovered among a ship's crew before it could be transmitted to the population on land. Finally, he boasts that he could sell the state of Italy to the Turks. He shows Peregrine how in his diary he takes detailed notes of his every action during every day.
Act Four, Scenes Two and Three
Lady Would-be, entering with Nano and two of Volpone's servant women, finds Sir Politic with Peregrine. Because she believes Mosca's lie, Lady Would-be suspects that Peregrine is a woman in disguise. Sir Politic cannot pacify her, so he leaves. Mosca enters and tells Lady Would-be that she is mistaken, that the woman he saw with Sir Politic is at the courthouse. He intends, of course, to convince Lady Would-be that it was Celia he saw with Sir Politic. Lady Would-be apologizes to Peregrine for the misunderstanding and, accompanied by Mosca, Nano, and the two servant women, exits the scene. In an aside, Peregrine vows revenge on Sir Politic, who, he believes, arranged this exchange with Lady Would-be as a practical joke.
Act Four, Scene Four
At the courthouse, Mosca makes sure that Corbaccio, Voltore, and Corvino are all familiar with the lie they are going to tell in order to protect themselves and condemn Bonario and Celia, whose story could ruin them. Mosca then assures them separately and secretly that they will inherit Volpone's fortune when it is all said and done. Finally, Mosca tells Voltore, the lawyer, that he has another witness who will testify against Celia. This witness is, of course, Lady Would-be.
Act Four, Scenes Five and Six
The four Avocatori, or judges, discuss how atrocious are the crimes of Volpone, Mosca, and Corbaccio, which have been brought to their attention by Bonario and Celia. The first Avocatore asks why Volpone is not present and Mosca introduces Voltore as his "advocate," or lawyer. The other three Avocatori insist, however, that Volpone be brought before the court. While Volpone is being summoned, Voltore asks to speak on his behalf. He then accuses Celia and Bonario of having an affair which left Corbaccio no choice but to disown Bonario. When the Avocatori protest that Bonario has always been upstanding, Voltore claims that this makes him more dangerous because no one would suspect him. He goes on to accuse Bonario of attempting to murder his father, and describes how Bonario entered Volpone's house, assaulted Volpone, and wounded Mosca before fleeing the scene with Celia. Bonario speaks up to discredit Voltore, but ends up losing favor with the Avocatori. When the Avocatori ask Voltore for proof, Voltore produces Corbaccio and Corvino who decry the honor of Bonario and Celia, respectively. At this, Celia faints. Mosca steps forward and claims that his wound speaks for itself.
As the Avocatori lean toward believing the testimony against Bonario and Celia, Lady Would-be appears and seals the deal, defaming Celia for supposedly seducing Sir Politic. Bonario and Celia state that their consciences and heaven are their only witnesses, but the fourth Avocatore replies, "These are no testimonies" (4.6.17). Again pretending to be feeble, Volpone enters the Scrutineo. Voltore argues that, in his fragile condition, Volpone could never have committed adultery. Voltore concludes his case by arguing that if Bonario and Celia's story is believed, then no one, not even the Avocatori themselves, is safe from slander. The Avocatori order Celia and Bonario to be taken away and commend Voltore for his service. Mosca debriefs Corbaccio, Corvino, Voltore, and Lady Would-be before they all exit.
Act Four, Scene One
The significance of 4.1 in the context of the play is not easily elucidated. As Marchitell has pointed out, Sir Politic with his get-rich-quick schemes acts as a foil for Volpone in this scene. However, Sir Politic qualifies more as one of "those that have your bare town-art" (3.1.14), that is, as described by Mosca, a lesser parasite who makes money by knowing his way around town. In contrast to Volpone's, Sir Politic's get-rich-quick schemes are essentially harmless, mostly because he never actually goes through with any of them. In Act Five, Peregrine uses one of Sir Politic's plots as a pretense to enact revenge.
Act Four, Scenes Two, Three, and Four
Lady Would-be continues to prove her gullibility and Mosca sets the stage for his courtroom charade. Temporarily, Mosca seems to have regained control of the situation. Having preyed upon Lady Would-be's jealous tendencies, Mosca intends to use her as a character witness against Celia at the Scrutineo. Meanwhile, Peregrine is an accidental victim. Analytically speaking, the meaning of these scenes lies mostly in the action that they set up. Figuratively speaking, these scenes represent the calm before the storm.
Act Four, Scenes Five and Six
Voltore delivers a fantastic performance as Volpone's advocate, living up to the reputation which, according to Mosca in 1.3, earned him Volpone's respect and inheritance. Though Mosca as well as each of the "clients" plays a role in exonerating Volpone, Voltore is the one who sticks his neck out the most. He exerts the most effort and takes the greatest risk in being Volpone's advocate because thereby he defies the very justice system which he was sworn to uphold. In terms of the play's structure, the sheer weight of his deception eventually leads Voltore to confess, which in turn leads Volpone to reveal himself. Thus 4.5 and 4.6 establish Voltore as a catalyst for Volpone and Mosca's downfall, which is, at this point, largely inevitable.
While Voltore makes his case, Bonario and Celia act almost as bystanders. As they watch the justice system fail them, they trust themselves completely to God's justice, submitting themselves to the judgment of heaven and conscience. For Jonson, this is the greatest good - sacrificing oneself to mankind's falsehoods for the sake of divine truth. According to Jonson, Bonario and Celia's stoicism is not only to be admired but also to be emulated.