Belief and faith
The gulls are "gullible," easily led to lend their belief to the tricks and plots of the conmen. The play itself is obsessed from the Prologue onward with the idea of what Coleridge would call the "willing suspension of disbelief," except that the gulls do not really start with much or any disbelief, and this is reality for them, not a story in which they believe the premises of a story in order to see what the author does with it. As Jonson’s audience, we know that the stories (and the whole play) are not real, so we are not gulled.
Or is Jonson playing any jokes on us as well? Belief of course is essential to theater, and the play's many metatheatrical forays play on this theme. Note how Jonson exploits theatrical convention to alienate the audience, such as when Surly, as a Spaniard, initially seems to be another character altogether.
Jonson, in portraying two Christian believers, explicitly considers whether there is a difference between having faith in the particulars of a Christian denomination—or having faith in God, or in anything transcendent—and believing in the false tricks of the conmen. All denominations cannot be completely right, so do some people believe because they have been conned rather than simply mistaken?
Alchemy and Transformation
Alchemical theory suggests that things are in a constant state of flux and transformation, and several parts of the play deal explicitly with this notion. Not only do the characters themselves transform into other characters, but their wares, their fears, and their faith are easily transformed into gold for the conmen.
Naturally, Subtle's status as "The Alchemist" is questioned throughout the play. What can he really transform, after all?
The process of alchemy itself is related explicitly to theater, because in addition to theatrical transformations, theater offers a world in which magical things can happen, and we often wish they would.
Gold
Gold is the result of successful alchemy, though the goal remains aspirational. It plays a large part in the play as the motivation for just about everything that happens. The gulls are all greedy for gold in order to achieve their dreams, and they are therefore greedy for the Philosopher's Stone. The conmen, inversely, are greedy for the gold they make by tricking the gulls into believing that they will eventually be rich.
Face's epilogue considers the fact that a theater audience similarly has handed over gold in order to be knowingly tricked with a false story on stage.
Theatricality
The play is set in 1610, a likely date for the play's first performance, and set in a house (to this day, a synonym for an auditorium) in Blackfriars. It is possible that the Blackfriars theater was the site of the play's London performances. The conmen are actors who take on roles to suit their audience, and in the end they trick the real audience as well as the gulls.
Constantly the processes of conning and believing are equated with the medium of theater. The questions in the play can nearly always be couched in theatrical terms. Note, too, moments which might be considered a play within the play, such as the Fairy Queen moments.
London in 1610
Jonson's play was a modern-dress play in its day, and it is hugely steeped in the culture of its time. The locations it names—the Temple Church, Deaf John's and the Pigeons Tavern, to name but three—were all close to the Blackfriars theater where the play was performed. The characters it satirizes, Anabaptists, Spaniards, and knights arrogant, would all have been familiar to the contemporary audience. Jonson similarly employs much modern slang for his characters. In some instances the language thus feels dense and dated.
Texts
Jonson's prologue in his Folio is addressed to the "Reader," and his play abounds with references to other texts, plays, and writers, which creates the impression that the play itself is in some way a patchwork of other texts.
The characters, particularly Subtle, also speak dense, technical jargon, as if to give the sense that their language is somehow plagiarized or borrowed from a better source.
Note that Dol's "noble lady" is a mad scholar of Broughton who quotes, "in her fit of talking," extensively from one of Broughton's works. The play quotes twice from Kyd's The Spanish Tragedy. Several other critics have found references and in-jokes to various other contemporary works.
"All things in common"
The play poses some interesting arguments about the nature of working and living together. Dol Common puts forward an eloquent defense of the need for the con to be a "venture tripartite" if it is to succeed. Interestingly, Dol's claims are expressed in the language of classical political thought, and the London of the play seems vaguely equated with a classical idea of democracy. Dol Common, in this reading, is not just a prostitute but the founder of an admittedly shaky commonwealth.
