Why has Molière endured? Maybe we’re attracted to his anarchism, the way his plays overturn the hierarchy of parents and children, masters and servants. Or maybe we just like potty humor. Constance Congdon, whose liberal adaptation of The Imaginary Invalid plays this month at PCS, seems to favor the latter explanation. Chris Coleman’s production puts a lot of impressive talent onstage in service of a hundred fart gags. Coleman’s invalid, David Margulies, brings to the role of Argan a befuddled, doddering disposition and Walken-esque cadence that makes the flatulent, selfish coot—who attempts to marry his daughter off to a preening doctor to save on the unnecessary medical care he delights in receiving—more likeable than he has any right to be. But why does one character have a thick French accent, and another speak like a gay George W. Bush? Why does the set employ the severe forced perspective of a cardboard theater diorama? And how long can we reasonably be expected to laugh at diarrhea jokes before they just get gross?