Volpone's satire is directed against "avarice," which can be thought of as greed that extends not just to money but also to all objects of human desire. The play's main thesis is stated by Volpone himself, "What a rare punishment / Is avarice to itself." The punishment—and the central irony of the play—is that while greed drives the search for money, power, and respect, it ends up making everyone in the play look foolish, contemptible, and poorer, both spiritually and financially. A similar idea is stated by both Celia, when she asks in III.vii, "Whither [where] is shame fled human breasts?" and by the judge at the end of the play in his plea that the audience should "learn" from the play what happens to those who succumb to greed, emphasizing that the play's stance on greed is a didactic one, intended to teach the audience what greed's real consequences are. Volpone himself starts out as an instrument of this lesson—he dupes the Corvino, Corbaccio and Voltore into parting with their goods in the hope of inheriting his—but ends up an object of the lesson as well, for succumbing to his greedy want for sensual pleasure.
There is a dichotomy in the play, never entirely resolved, between the devices of stagecraft and the conveyance of moral truth. In other words, there is a tension between the play itself (a play which, Jonson hopes, will be of moral value to those who see it) and what goes on in the play, in which the devices of stagecraft that are involved in the play's actual production are a source of deceit, confusion, and moral corruption. In other words, Volpone does not merely lie, nor he does not merely deceive; he makes an entire production out of his game, using a special eye ointment to simulate an eye infection, creating a character (the sick Volpone) using wardrobe, make-up, and props. He too seems to share the intention to expose moral folly, with the playwright, Jonson; but this is in the end seen to be another illusion. Likewise, Mosca and Voltore put on a production to convince the judges of their innocence. They use rhetoric and poetry to tell a story, complete with a shocking "surprise witness" and the graphic use of imagery (the appearance of "impotent" Volpone). The play thus exposes us to many different forms of theatrical illusion as methods of lying, perhaps in the hope of allowing us to better discern which forms of theater are sensationalistic, unhelpful, and inaccurate in their portrayal of reality.
"Everyone's a parasite" to paraphrase Mosca (III.i), and over the course of the play he is proved right, in the sense that everyone tries to live off of the wealth or livelihood of others, without doing any "honest toil" of their own. Corvino, Corbaccio and Voltore all try to inherit a fortune from a dying man; and Volpone himself has built his fortune on cons such as the one he is playing now. Parasitism, thus portrayed, is not a form of laziness or desperation, but a form of superiority. The parasite lives by his wits, and feeds off of others, by skillfully manipulating their credulity and goodwill.
Volpone, both in his initial speech in Act I and in his seduction speech of Act III, mixes religious language and profane subject matter to a startling poetic effect. In Act I the subject of his worship is money; in Act III it is Celia, or perhaps her body, that inspires prayer-like language. As a foil against this, Celia pleads for a distinction to be restored between the "base" and the "noble," (in other words, between the profane—that which is firmly rooted in our animal natures, and the sacred—that which is divine about humans. Through their respective fates, the play seems to endorse Celia's position, though Jonson invests Volpone's speeches with a great deal of poetic energy and rhetorical ornamentation that make his position attractive and rich, which is again, another source of tension in the play.
Jonson creates a complex relationship among disguise, deception, and truth in the play. Disguise sometimes serves simply to conceal, as it does when Peregrine dupes Sir Politic Would-be. But sometimes it reveals inner truths that a person's normal attire may conceal. Volpone, for example, publicly reveals more of his "true self" (his vital, healthy self) when he dresses as Scoto Mantua; and Scoto's speeches seem to be filled with authorial comment from Jonson himself. Furthermore, disguise is seen to exert a certain force and power all of its own; by assuming one, people run the risk of changing their identity, of being unable to escape the disguise. This is certainly the case for Mosca and Volpone in Act V, whose "disguised" identities almost supersede their actual ones.
Gulling means "making someone into a fool." The question that the play teaches us to ask is who is being made a fool by whom?. Volpone plays sick to make the legacy-hunters fools, but Mosca plays the "Fool" (the harmless assistant and entertainer) in order to make Volpone into a fool. To make someone else into a fool is both the primary method characters have for asserting power over one another and the primary way Jonson brings across his moral message: the characters in the play who are made into fools—Corbaccio, Corvino, Voltore, Volpone—are the characters whose morality we are supposed to criticize.
As the seat of greed, corruption, and decadence, at least according to the prevailing prejudices, Venice was the beneficiary of years of stereotype in English drama. Italians in general were seen as sensuous, decadent beings, thanks to their extremely sophisticated culture, history of Machiavellian politicians (Lorenzo de Medici, Cesare Borgia, Machiavelli himself) and beautiful (and often erotic) love poetry. Though not things considered particularly awful today, this type of decadence made English people wary of being infected with immorality, and Venetians were seen as the worst of the bunch. The direct influence of the "power of Venice" to corrupt can best be seen in the Sir Politic Would-be subplot, where the English knight Sir Politic "goes Venetian" and becomes a lying would-be thief. But the Venetian setting probably made the story more believable for most English audiences, signifying the fascination of the play with disguise and deceit, though also, perhaps against Jonson's intentions, distancing them from the play's moral message, by placing the greed in a historic far away place traditionally associated with greed, instead of right in the heart of London.
There is a "fable" running throughout the play, through the associations the characters' names create with animals. It is very simple and tells the tale of a cunning "Fox" (Volpone in Italian), circled by a mischievous "Fly" ( Mosca in Italian), who helps the Fox trick several carrion-birds—a vulture (Voltore), a crow (Corvino) and a raven (Corbaccio) into losing their feathers (their wealth). The animal imagery emphasizes the theme of "parasitism" in the play, where one life form feeds off of another. And it should also be remembered that fables are tales with simple moral messages, told for a didactic purpose. Though much more complex, Volpone, at its heart shares the same purpose, making the use of "fable-like" symbolism appropriate and helpful in understanding the meaning of the play.