Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Mocking, Satiric
Just like every single episode of The Simpsons, Ben Jonson's The Alchemist is all about satire.
That means Jonson uses a boatload of humor, irony, and sarcasm to make fun of his characters and their flaws. (The play is chock-full of folks who are greedy, hypocritical, silly, and just plain foolish.)
Supposedly, the whole point of using a mocking tone is to improve society by exposing how ridiculous people can be. Basically, Ben Jonson was the John Oliver of his time. In The Alchemist, Jonson takes aim at London society in the early 1600's.
Check out what he has to say in the opening Prologue:
Our scene is London, 'cause we would make known,
No country's mirth is better than our own: (Prologue, 5-6)
Gee. That's starting to sound a little patriotic...until we get to the next lines, where Jonson tells us why London is such an awesome place:
No clime breeds better matter for your whore,
Bawd, squire, impostor, many persons more, (Prologue, 7-8)
Nope. He's not exactly flattering his original audience members, now is he? He takes it a step further by inviting his "judging spectators" to think about whether or not they recognize any of their (our?) own flaws being reenacted on stage.