But a larger question, Mr. Parnell said in an interview, is “what it means to be a scientist” when confronting issues of faith. It is an idea as controversial today as it was then.  Darwin’s Britain teemed with religiosity as diverse as evangelical Christian fervor and spiritualism, an idea whose adherents included Wallace and Darwin’s wife, Emma Wedgwood. Darwin knew he would be called heretical for challenging the Biblical idea of God as a one-time-only creator of an immutable natural order.  At first, he finds the idea literally sickening. But, as Mr. Parnell put it, Darwin is “both great enough and grandiose enough” to eventually conclude not just that he could do it, but that he ought to. And we all know how that came out.  But today as then, there are creationists who assert that people must choose between belief in Darwin’s theory and belief in God. Yet Darwin did not kill God. His theory, unchallenged in science, is the foundation on which the edifice of modern biology is built. And it has plenty of adherents among religious believers.  “Trumpery” is not the first foray into science for Mr. Parnell, a screenwriter and dramatist who has worked on television shows like “The West Wing” and who teaches television writing at the Yale School of Drama. That would be “QED,” a play about Richard Feynman, the physicist and theorist of quantum electrodynamics, the modern theory of electromagnetism.  It was while working on that play that Mr. Parnell stumbled on a book, “The Song of the Dodo” by David Quammen, which describes Wallace’s work. The book led Mr. Parnell to more study of Darwin, Wallace and their times. Pretty soon, he had a three-act play with, he realized, a cast of way too many characters dealing with way too many subjects — not just evolution, but topics like Colonialism and a Tierra del Fuegan accused of murder.  “I didn’t know for a long time what the play was about,” he said.  But just as “QED” focused sharply on Feynman, Mr. Parnell found this play by focusing on Darwin and telescoping some of the events in his life to bring his quandaries into sharp relief.  For example, much of the play is an argument involving Darwin, his biological allies Joseph Hooker and Thomas Henry Huxley, and their foe, Richard Owen. In fact, their debates took place in letters. But confrontation is useful for a dramatist dealing with science.  “The ideas have to be accurate, they have to be intelligible,” Mr. Parnell said. “But you have to find a dramatic way to tell it — a reason it can be a play, to exist on stage.”  He added, “It has to be grounded in conflict.”  “Trumpery” is not Mr. Parnell’s first exploration of a frightening idea either. That was “And Tango Makes Three,” a children’s book he wrote with his partner, Justin Richardson. The book tells the true story of Silo and Roy, two male penguins at the Central Park Zoo who courted each other and formed a relationship. When a keeper saw them trying to incubate a rock, he gave them an orphaned egg, which they cared for until it hatched as the chick Tango.  While the book received many favorable reviews, some parents and religious groups objected to it as suggesting that a family could be something other than Mom, Dad and kids.  “That idea is considered dangerous,” Mr. Parnell said.  Today, although Darwin’s idea is not so frightening to many, the conflict over evolution still plays on, on stage and in school boards and courtrooms around the country. Perhaps conflict is inevitable when people confront new and frightening ideas. But, as Darwin tells his dying daughter Annie, at the end of the play, it is good to challenge conventional wisdom. He adds, though, “if you question everything, you have to expect to be scared.”  A version of this article appears in print on , on Page F3 of the New York edition with the headline: Darwin’s Era, Modern Themes: Science, Faith and Publication. Order Reprints| Today's Paper|Subscribe
“Trumpery,” a play that opened this month in New York, explores a period teeming with religiosity and controversy.