A few years ago, I wrote an essay in praise of the Harry Potter books that yielded some interesting responses. One man, knowing that I am a Christian, wrote in some astonishment: Did I not see that the books symbolically describe an alchemy-based paganism, a model of magical power deeply hostile to Christianity? The key, he said, was to be found primarily in the names of the main characters, which referred to different stages of the alchemists’ wisdom, and in animals like the phoenix Fawkes”the phoenix being a major symbol, for the alchemists, of transformation.

I did not find these arguments strong at the time, and I grew more dubious a few weeks later when I received a letter from another Potter scholar who claimed that the books did indeed have a hidden meaning but a specifically Christian one. According to this interpreter, my first correspondent was right in thinking that the phoenix was deeply significant but wrong about what it signified: Far from being anti-Christian, the phoenix is a symbol of the Resurrection of Jesus, and the whole Harry Potter series is a covert retelling of the Christian narrative.

My two correspondents may have come to opposite conclusions, but on a deeper level they were confederates: fellow believers in the Gospel of the Hidden Meaning. And they have plenty of company. The world is full, it sometimes seems, of people who think that what writers do is encode secret messages, and what readers, therefore, should do is decipher them.

For example, Michael Drosnin’s Bible Code volumes of 1997 and 2002 suggest that by examining sequences of letters”every sixteenth letter, say”in the text of Scripture, we can discover prophecies of contemporary events. (This idea is actually quite old; it was practiced, for instance, in thirteenth-century Spain by Rabbi Bachya ben Asher.) Among much else, Drosnin discovered that the Bible Code prophesied the attacks of September 11, 2001”which would, of course, have been much more impressive if he had discovered it before the bombings rather than after.

Meanwhile, in 2005 Claire Asquith published Shadowplay: The Hidden Beliefs and Coded Politics of William Shakespeare, a book arguing at great length that Shakespeare’s plays consist of a series of coded messages to English Catholics expressing the playwright’s devotion to their faith and their cause. Much the same argument had been made a year earlier by Richard Wilson in his book Secret Shakespeare”though, as the scholar Anne Barton recently remarked in the New York Review of Books, Asquith and Wilson rarely agree about how any particular passage or place or character in the play actually illustrates Shakespeare’s Catholicism. Wilson thinks Belmont, the home of Portia in The Merchant of Venice, portrays the country house of an English Catholic family; but Asquith thinks Portia is an image of the very Protestant Queen Elizabeth. It turns out that the secret meaning of Portia is as tough to figure out as the secret meaning of Fawkes the phoenix.

And then, of course, there is The Da Vinci Code, which has encryption and decryption as its raison d’etre. It’s hard not to suspect that, as a child, Dan Brown found a secret decoder ring in his breakfast cereal and never really got over it. Nearly every name in the book is an anagram of some other name, and encryption comes so naturally to Brown’s characters that when one of them is dying from a gunshot wound, he still has the resourcefulness to make anagrams of the messages he needs to write with an invisible-ink pen”no doubt another cereal toy from Brown’s childhood”and even in his own blood. It’s easy to get into the spirit of all this: Sony Pictures uses the invisible-ink message to name its website for the movie (sodarktheconofman.com), and Justice Peter Smith, the British judge who recently determined that Brown had not plagiarized other books, implanted a comical “Smithy code” into the text of his own ruling”using not Brown’s preferred method of the anagram but rather a series of apparently accidental italic letters (more like The Bible Code).

What is the appeal of this kind of thing? Why is it so recurrently popular? There’s a wonderful passage in Tolstoy’s War and Peace where one of the main characters, Pierre Bezukhov, discovers that if you assign a number to each letter of the alphabet, the words L’Empereur Napoleon add up to 666”the number of the Antichrist. Then Pierre, because he imagines himself as Napoleon’s great antagonist, starts trying to write his own name in such a way that it also adds up to 666 and finds that he cannot, even after he changes the spelling in several different ways. But finally, he decides not only to alter his name’s spelling but also to indicate his nationality, and finally to abandon correct French usage: “L’russe Besuhof,” astonishingly, yields 666. “This discovery excited him,” Tolstoy notes with the straightest of faces. “How, or by what means, he was connected with the great event foretold in the Apocalypse he did not know, but he did not doubt the connection for a moment.”

Well, there’s part of the answer: the sense of suddenly being plugged into a vast world-historical event, into pure meaning, remains enormously appealing”especially when it’s a meaning others cannot see. The Da Vinci Code, of course, is fiction (especially the parts Dan Brown claims to be fact), while the Asquith and Wilson books are based on extensive research and depend on significant historical knowledge. Even so, the differences are less significant than one would think. All such books are based on pure supposal: Let’s suppose that Shakespeare was a crypto-Catholic who hid Catholic messages in his plays, or that the authors of the Bible hid secret messages within the text, or whatever.

If you begin by supposing something to be true that there is simply no reason even to suspect is true and then look for any evidence that might be construed as supportive of that supposal while resolutely ignoring any evidence that might be construed as refuting that supposal”well, then, you’re quite likely to find yourself in the position of Pierre Bezukhov, amazed by how a scarily intricate story holds together.

Mathematicians-striving, often unsuccessfully, to remain calm-voiced and to soothe the frenzied thumping of their temples”reply that an elementary knowledge of probability will reveal that such correspondences aren’t surprising at all. Logicians reply that not only have these code breakers cooked the books by manipulating the data but they have also overlooked dozens or hundreds of far more likely correspondences. Skilled literary critics reply that if you define a character or a thing or an event in a story vaguely enough, it can become a symbol of almost anything. (Thus the old story of the high school English teacher who argued that Robert Frost’s poem “Stopping By Woods on a Snowy Evening” is about Santa Claus. Who else is in the snow-covered woods, at night, with promises to keep and miles to go before he sleeps?)

But it’s easy, when thrilled by the prospect of making a discovery, to see that which has been hidden to all or at least to most, to become part of what C.S. Lewis called an Inner Ring”the Ring whose goose-bumps-inducing catchphrase is always “We few””to forget that some supposals are better than others. That Shakespeare was a secret Catholic is indeed plausible; that Shakespeare wrote plays to send secret messages to his fellow Catholics is far less so. But such distinctions are easily elided. Indeed, code breakers have an interest in eliding them and in rushing quickly past inconveniently slippery information.

For instance, Father Andreas Kramarz, writing recently in the National Catholic Register (largely about Hildegard Hammerschmidt-Hummel’s book The Hidden Existence of William Shakespeare: Poet and Rebel in the Catholic Underground), is careful throughout most of his article to maintain the proper reserve, with all the appropriate ifs and may-haves and could-haves, but he never pauses to consider any alternative to the Great Supposal of the poet’s Catholicism. Nor are the putative solid facts of the case as solid as Fr. Kramarz”relying, I imagine, on Hammerschmidt-Hummel”believes.

Take this straightforward sentence: “For seven years, William was taught at the Latin school by Simon Hunt, a Catholic.” But the only available records say that Simon Hunt was the schoolmaster in Stratford for just four years, leaving when young Will Shakespeare was eleven. Moreover, while it seems very likely that Shakespeare attended this school, we cannot be sure of even that, for no school records have survived. And there was a different Simon Hunt who died in Stratford around 1598; if he had lived there for any length of time, he could have been Will’s teacher, not Simon Hunt the known Catholic. When that Simon Hunt left Stratford in 1578, he went to the great English Catholic college at Douai in France, where be studied for the priesthood, receiving ordination and joining the Society of Jesus three years later.

To some scholars, this renders full of import the mention of Rheims in The Taming of the Shrew. But Gremio only says that Lucentio “hath been long studying at Rheims” and is “cunning in Greek, Latin, and other languages.” If that is sufficient, as some think, to suggest that Shakespeare studied there himself, what are we to make of the fact that Hamlet is a student at Wittenberg? Does that mean Shakespeare was a Lutheran?

This ceaseless over-reading of trivia makes scholars look like cranks and often has the effect of making legitimate evidence seem guilty by association. For there are good reasons, biographical and even textual, to suspect that Shakespeare was a Catholic. His father almost certainly was a committed Catholic; several other members of his family definitely affirmed the Old Faith; he had many personal associations with Catholic families. And then there is the powerful presence of the Ghost in Hamlet, the father of the young prince and student at Luther’s Wittenberg, who returns to tell his son that he is “Doom’d for a certain term to walk the night, / And for the day confin’d to fast in fires, / Till the foul crimes done in my days of nature / Are burnt and purg’d away”” as straightforwardly Catholic a portrait of Purgatory as one could hope for. No wonder Hamlet says to his school friend, “There are more things in heaven and earth, Horatio, / Than are dreamt of in your philosophy.” The “your” is telling.

Yet even so, Shakespeare’s King John articulates the church-state disputes of the thirteenth century in curiously anachronistic and distinctively Anglican terms, such that some characters anticipate the antipapal arguments common in the time of Henry VIII and his children. (An English Jesuit named William Sankey, working at the English Catholic college at Valladolid, Spain, in the 1640s, censored Shakespeare’s plays for his students and went through King John with a particularly heavy pen. There is no evidence that he discerned any pro-Catholic messages in the other plays.)

More to the point, even if it could be established that Shakespeare was a Catholic, that task is trivial in comparison with the challenge of showing that his plays encode his Catholic concerns. Stephen Dedalus, in James Joyce’s Ulysses, articulates a complex argument that many of Shakespeare’s plays tell a kind of secret family history, redescribing in multiple ways the unfaithfulness of his wife, Anne, lonely in Stratford, with the playwright’s brother Richard. If Shakespeare wrote coded plays at all, why not that code? Stephen actually accounts for certain recurrent character types and scenes in Shakespeare’s plays better than Asquith or Wilson does, but what all the Shakespearean code breakers have in common is a tendency to assume that Shakespeare shares their own concerns.

Stephen Dedalus has a tortured family life that dominates his thinking; he assumes the same of Shakespeare. Wilson works in an academic environment obsessed with the relations between literature and politics; he assumes that Shakespeare had similar obsessions. Asquith got the idea for her book after watching”with her husband, a British diplomat”a Cold War-era dramatization, in Moscow, of some Chekhov stories. Noting that the plays were full of political subtexts that everyone in the audience laughed at, she began to suspect that Shakespeare’s plays could have been similarly encoded and concerned with similar issues.

Even assuming that Asquith, Wilson, Hammerschmidt-Hummel, et al. could agree on what is encoded in the plays, there remains the question of why. Any message that could be decoded by Shakespeare’s fellow Catholics could also be decoded by Elizabeth’s Catholic-hunting spies, who surely were just as likely to show up for a nice evening at the theater as anyone else. So why run the risk? What would Shakespeare be trying to communicate, and for what purpose? When Portia’s favorite suitor chooses the leaden casket, the third offered, does that mean “Meet a member of the Montague family in Leadenhall Street on the third day from today”? (Wilson thinks that Portia represents the great English Catholic family the Montagues partly because she lives in Belmont. Asquith’s association of Portia with Queen Elizabeth is at least a little more reasonable, since they share the experience of being besieged by suitors. Even so, isn’t it worth noting that Elizabeth rejected all of hers, whereas Portia eagerly chooses Bassanio?) I have scoured the pages of these writers trying to get answers to these questions but with little success. The idea that the plays hold any secrets or hidden messages is the most dubious of them all.

Even quite serious humanistic scholars can lose sight of probabilities and complexities when captivated by a thesis”especially since, unlike their counterparts in the sciences, they tend not to create control groups, even as thought experiments. And, of course, there are still fewer restraints on those like Dan Brown who just make stuff up. As the great Anglican scholar N.T. Wright”now bishop of Durham but formerly canon theologian at Westminster Abbey”has pointed out, Brown “makes gaffe after gaffe which could have been corrected by ten minutes of walking around with his eyes open. The abbey has towers, not spires. You cannot see parliament from St. James’s Park. College Garden is an extremely private place, not ?a very public place’ outside the abbey’s walls. You cannot look out into it from the chapter house; nor is there a ?long hallway’ leading to the latter, with a ?heavy wooden door’ at the end. Ten minutes’ observation by a junior research assistant could have put all this right. If Brown is so careless, and carelessly inventive, in details as easy to check as those, why should we trust him in anything else?”

None of this matters to someone caught up in the rapture of discovery, of suddenly seeing the meaning that was there all along”and this too is an important element of many of these stories of decryption, the “hidden in plain sight” motif. The secret just waited to be noticed, like Poe’s purloined letter. Why did I never see the angle of Jesus’ limbs in Leonardo’s painting of the Last Supper, or the fact, so obvious now that Dan Brown’s characters point it out, that the disciple on his right hand is a girl? This is one of the reasons these sorts of interpretations tend to attach themselves to the most famous books and artworks: The whole world has been looking at this and never figured it out.

And, of course, the pleasure is intensified by the fact that others are still in the dark. Isn’t the greatest pleasure offered by the Catholic-Shakespeare books the thrill of imagining ourselves as a secret Catholic there in the Globe Theatre, receiving every single one of the Bard’s coded messages like arrows shot right into our chests, while the rabble and the groundlings surround us with their blank ignorance? We stand there like St. Sebastian, stuck full of shafts while our eyes glaze over in ecstasy.

Above all, I think, these fanciful tales appeal to what I can only call our plain laziness. The interpretation of literary texts is actually hard work. You have to know a great deal about the history of culture and about the various forms and genres and techniques of literary writing to have a shot at really figuring out a major work of literary art.

Likewise, the understanding of paintings”especially paintings made centuries ago by people who thought very differently than we think, who lived in a very different social world, whose ideas of what paintings represent and how they represent it are often quite alien to what we take for granted”is achievable only by years, even decades, of scrupulous attentiveness to work after work after work. And the deepest wisdom about the productions of culture will always acknowledge the possibility of error, will always see that subtle alterations in how we think of this detail or that theme can result in quite dramatically different pictures of the work as a whole.

But the code breakers offer a much more consoling message. They tell us that we don’t need to read carefully or think hard or labor for years on end. All the work that needs to be done they have already done. Understanding is nothing more than putting the right key in the right lock. They have the key; smiling, they hold it forth to us. All we have to do is take it”after, of course, paying them a fee that is really quite trifling in comparison to the weight of the wisdom they proffer.

Alan Jacobs is professor of English at Wheaton College and author of The Narnian: The Life and Imagination of C.S. Lewis.