Before they rehearse, the mechanicals must deal with (what they think are) some thorny theatrical problems.
One concerns moonlight. Pyramus and Thisbe meet secretly by moonlight, and the mechanicals can’t figure out how to bring moonlight into the great hall of the palace. They consider just opening a window and letting the real moonlight shine in, but in the end they decide that they must have an actor come in with a lantern to present the figure of Moonlight, and explain to the audience that he’s shining light on the scene.
The joke, of course, is that this isn’t how theater works. If you want moonlight, you have someone say, “the moon is so bright tonight,” and your audience will understand. Or, as Shakespeare had just done, you have a character—the very character who decides they need someone with a lantern—say, “meet me in the palace wood..by moonlight,” and you’re done. Shakespeare thus subtly contrasts his own theatrical prowess with the inept, stumbling mistakes of this comical troupe.
A more difficult problem concerns the lion. The story of Pyramus and Thisbe turns on a lion attacking Thisbe: she escapes, but Pyramus finds her torn scarf and thinks she’s been killed; he kills himself; when she finds him dead, she kills herself. So they must have a lion. But they are very worried about presenting too terrifying a lion, and scaring the ladies of the court. Given their lack of talent, this was never a true concern, but nevertheless they decide that the actor playing the lion must first speak directly to the audience, explaining who he really is and entreating them not to believe for a moment that he is actually a lion.
Why is this funny? Why do we laugh at such decisions by the rude mechanicals? More broadly, why is “Pyramus and Thisbe” the comic highlight of the play?
At the heart of these questions are fundamental issues of theatrical control. Theater involves very complicated power relationships between actors and audiences. Describing a great performance, we might say, “She had the audience in the palm of her hand,” or “I was transfixed”—or “spellbound,” or “overcome,” and so on. Good theater overpowers us, takes control of us, enraptures us. This is one reason that plays always end with applause, and the company bowing to the audience: the actors have been controlling us, but now they submit to our approval, hand all the power back to us. “If we shadows have offended,” begins Puck’s apology for the play, begging forgiveness from the audience.
So there is a way in which the concerns of the rude mechanicals are appropriate, even though it’s hard to imagine their theater being overwhelming. There would be, perhaps, something inappropriate about common artisans holding an aristocratic audience under their theatrical sway, so they work as hard as they can to avoid that happening. And it’s worth noting that even though “Pyramus and Thisbe” is a disaster in theatrical terms, it’s a great success otherwise: Theseus is indeed greatly entertained by it, which is all the mechanicals wanted to achieve.