Greed
The theme of greed pervades the entire play. It is embodies by Volpone, Mosca, and all the "clients." In his opening soliloquy, Volpone displays how utterly consumed by greed he is. In a sense, greed defines the major conflict of Volpone. Volpone's scam is born of his own greed and fed by the greed of his "clients." After Mosca compares Celia's beauty to that of gold, Volpone's greed inspires unconquerable desire for her. Because greed is all that he knows, Volpone even resorts to it as a tactic for seducing Celia. Ultimately, it is greed which causes Volpone and Mosca's downfall. Because they cannot agree to share the fortune in 5.12, Volpone unmasks himself and brings Mosca down with him.
Animalization
Animalization, that is, Jonson's representation of characters as their namesake animals, transforms Volpone into a kind of fable. Arguably, the characters are not as one-dimensional as their names might suggest, but their names are fitting, memorable, and, most importantly, descriptive. If the names of Jonson's characters can be considered predictors of their actions, then the majority of the play's action comes as no surprise to the audience. Combined with the Argument, the Animalization theme reveals the motivations of every character. As a result, the audience can focus more readily on the underlying meaning of the play instead of the how and the what.
Parasitism
Although Mosca is the foremost parasite in the play, Corvino, Corbaccio, and Voltore might well be considered parasites as well. Certainly, Volpone's entire scam depends on Mosca's keen ability to leech his clients, but if not for the clients' desire to leech Volpone, the scam would fall flat. Volpone, Mosca, and all the clients are, in fact, competing parasites.
Parasitism is an explicit theme of the play as it emerges from Mosca's soliloquy in 3.1. Here, Mosca expresses his opinion that parasitism is a universal guiding principle: that is, everyone is a parasite, but some are better at it than others. In the case of Volpone, this principle rings true. Few characters in the play act honestly; all seem willing, instead, to use any means to secure Volpone's fortune. They are all parasites, flies and carrion birds competing over Volpone's dying carcass. Only Mosca, however - the cleverest parasite of all - is fully aware of his parasitic status. Thus, arguably, he is best able to manipulate others.
Metatheatricality
The theme of metatheatricality is revealing. Although there are only a few scenes which qualify as plays-within-a-play, Jonson's criticism of Elizabethan theater emerges from each. In 1.2, Mosca's account of the transmigration of Pythagoras's soul is truly obscene. In order to produce a few chuckles from Volpone, Mosca debases an unparalleled philosopher and mathematician.
From Jonson's perspective, as expressed in the Epistle and the Prologue, this kind of lowbrow humor is a travesty. Volpone, who appears to enjoy theater, is without a doubt in desperate need of moral education. Jonson argues that Volpone's love of theater provides the perfect opportunity to "inform [him] in the best reason of living." As shown by the low quality of Nano's recitation, Jonson believes that the Jacobean theater is lacking in this function. Volpone is intended to demonstrate refined, serious, Classically-influenced comedy that might instruct rather than simply amuse. Of course, ironically, that does not make his plays-within-the-play any less amusing.
Vengeance
Though it is sparingly present in the main plot, the theme of Vengeance is much more prominent in the subplot of Volpone. The story of Sir Politic and Peregrine, besides being a warning to the English state, points out the ludicrousness of traditional vengeance. Peregrine, who only thinks he has been wronged, drives Sir Politic to leave Venice merely for the satisfaction of saying "Now, we are even" (5.4.74). If nothing else, this parable teaches us that vengeance is a childish pursuit.
Deception
Like greed, deception pervades the entire play. As a theme, deception has the effect of marking characters for punishment. In the main plot of Volpone, Jonson's sense of poetic justice is such that any character who deceives another is ultimately punished. Bonario and Celia, who never engage in deception but who are honest to the last, are exempted from punishment. Meanwhile, Mosca, Volpone, and the rest of the clients all get their comeuppance.
Knowledge/Ignorance
At any given time during the course of the play's action, no characters on stage know as much as the audience; they are all thus ignorant, though some are more ignorant than others. Jonson's extensive use of dramatic irony ensures that only the audience is fully aware of each character's situation. Not even Mosca, the master puppeteer, knows that Corvino and Celia will come to the door earlier than expected and that, as a result, Bonario will leap out and discover Volpone's scam. Jonson plays with the knowing position of the audience, inviting us to consider their moral failings from an unsurprised position. Thus he equates ignorance with moral chicanery and knowledge with moral instruction.
This knowledge-ignorance dialectic develops the conflict of both the main plot and the subplot. Sir Politic, who epitomizes ignorance, and Peregrine, who epitomizes knowledge, clash in predictable ways. On the subject of the mountebanks, for example, Peregrine has his reservations but Sir Politic declares that "They are the only knowing men of Europe!" (2.2.9). And, however ironically, Peregrine is supposedly being instructed by Sir Politic in the ways of a gentleman traveler. Sir Politic and Peregrine's interaction might best be summarized by the maxim which says, "Wise men learn more from fools than fools from the wise."
