“Anonymous,” a costume spectacle directed by Roland Emmerich, from a script by John Orloff, is a vulgar prank on the English literary tradition, a travesty of British history and a brutal insult to the human imagination. Apart from that, it’s not bad.

First things first. The film’s premise is that the plays and poems commonly attributed to William Shakespeare are actually the work of Edward de Vere, 17th Earl of Oxford. This notion, sometimes granted the unwarranted dignity of being called a theory, is hardly new. It represents a hoary form of literary birtherism that has persisted for a century or so, in happy defiance of reason and evidence. The arrival of “Anonymous” has roused Shakespeareans more learned than I to the weary task of re-debunking — in the past two weeks The New York Times has published both an Op-Ed piece and a Sunday magazine Riff opposing the Oxfordian position — and to their cogent arguments I can offer only a small corrective. This is a Roland Emmerich film. (At least I assume it is, though I guess, in the spirit of the enterprise, I should be open to other possibilities. Joe Swanberg? Brett Ratner? Zhang Yimou? It all seems eerily plausible, once you start to think about it.)

My point is that it might be a mistake to suppose that the director of “10,000 B.C.” — to mention only the most salient example — should be taken as a reliable guide to history. Perhaps he and Mr. Orloff (“Legend of the Guardians: The Owls of Ga’Hoole”), rather than advancing the case for Edward de Vere, set out to undermine it by exposing the absurd prejudices and fallacies on which the hypothesis rests. These can be boiled down to a sentimental and reactionary fantasy of class. How could Shakespeare, the half-educated son of an unlettered provincial glove maker, have written all those masterpieces? Surely it is more plausible to suppose that they were the work of one of his betters.