Monthly Archives: June 2021

Probability Theory, Moral Certainty, and Bayes’ Theorem in Shakespeare’s OTHELLO

Marionet Teatro
Theatre about Science Conference
University of Coimbra, Portugal
November 25-27, 2021
Edwin Wong

Probability Theory, Moral Certainty, and Bayes’ Theorem in Shakespeare’s Othello

Thank you to the organizers for putting this wonderful event together and thank you everyone for coming. It’s great to be here. I’m Edwin Wong. I specialize in dramatic theory based on chance, uncertainty, and the impact of the highly improbable. My first book, The Risk Theatre Model of Tragedy, presents a new theory of tragedy where risk is the dramatic fulcrum of the action. The book launched The Risk Theatre Modern Tragedy Playwriting Competition, the world’s largest competition for the writing of tragedy, now in its fourth year ( Today, I’ve come all the way from Victoria, on the west coast of Canada, to talk about the intersection between theatre and probability theory in a play we all know and love: Shakespeare’s Othello.

Now, the first thing people ask when I say “theatre” and “probability theory” is: “How do you bring probability theory to theatre? How would you know the odds of something happening or not happening? —every event, even chance events, are purposefully written into the script by the playwright.” They ask: “Where is the probability in theatre?”

It’s there. Look at the language of probability in Othello. In Othello, Shakespeare talks of “proof,” “overt test,” “thin habit and poor likelihoods,” “modern seeming,” “probal [i.e. probable] to thinking,” “exsufflicate [i.e. improbable] and blown surmises,” “inference,” “prove it that the probation bear no hinge nor loop,” “I’ll have some proof,” “living reason,” “help to thicken other proofs that do demonstrate thinly,” “speaks against her with the other proofs,” and so on. The language of probability permeates the play.

The language of probability permeates Othello because, in this play, no one is as they seem. “I am not what I am,” right? Iago seems honest; he’s anything but. Othello seems a man for all seasons; he is, however, quite fragile. Desdemona seems unfaithful; she is, however, true. Emilia seems to have loose morals; she sticks to her morals, however, even when threatened with death. There’s a disjunction between seeming and being. Othello and Iago talk about it: “Men should be what they seem,” says Iago, “Or those that be not, would they might seem none.” Because seeming and being are at odds, you can guess what a person’s intentions are, but you may never know.

This brings us to the crux of the play: your best friend who you’ve stood shoulder-to-shoulder with in wars and who’s known for his honesty, is telling you your wife is getting it on with your lieutenant. You’re a little bit older, having “declined into the vale of years.” Your wife is young, as is your lieutenant. But, you love your wife very much and she seems constant. At the same time, you also trust your best friend. What do you do?

This is what Othello decides. If the allegations are true, he’ll kill Desdemona and Cassio. If they’re false, he’ll kill Iago. Someone will die. The problem is, how does he decide who dies? There’s no proof. Nor is proof forthcoming: Iago and Othello establish that Desdemona and Cassio, if they’re guilty, aren’t going to confess. And, because they’re subtle lovers, Othello’s not going to catch them in the act. In the real world, you could probably catch them, sooner or later. But that’s not the world of the play that Shakespeare’s created: in this play, there’s only seeming.

So, Othello will kill. Who he kills will be based on belief and probability. He can’t decide. But Iago helps him. He comes up with the test of the handkerchief. Now, the test of the handkerchief isn’t certain, but in the world of the play, nothing is certain; there’s only probability. Othello has given Desdemona a special handkerchief. Iago suggests that, if the handkerchief makes its way into Cassio’s hands, then Othello can take this as proof. Conversely, if Iago cannot demonstrate this, Othello can take this as proof Iago is lying. Lives hand in balance.

In their rush to dinner, Othello and Desdemona accidentally drop the handkerchief. Emilia, by chance, finds it, and, knowing that Iago is always asking about it, gives it to Iago. Iago plants the handkerchief in Cassio’s bedroom where Cassio finds it and asks his ladyfriend Bianca to copy the design: the napkin is of an unusual provenance, “spotted with strawberries.” Bianca, however, thinking the handkerchief a gift from some new woman, gets jealous and squabbles with Cassio. Iago, meanwhile, has set things up so that Othello sees Cassio with the handkerchief. Once he sees the handkerchief, he’s convinced: Cassio and Desdemona are getting it on.

Is Othello, jumping to this conclusion, being reasonable? The first great Othello critic, Thomas Rymer, found Othello’s actions laughable. He came up with a jingling couplet to express his distaste, saying: “Before the Jealousie be Tragical, the proof may be Mathematical.” Most people, I believe, would agree with Rymer and say: “Othello, what are you doing?!?”

Enter probability theory. In probability theory, there’s a tool called Bayes’ theorem. It’s used to calculate conditional probabilities. With it, you can revise probability estimates as new information comes to light. This is exactly what happens in Othello: new evidence—the handkerchief—comes to light that makes Othello revise his initial probability estimate. In Iago’s words, the napkin “speaks against her with the other proofs,” or the napkin “may help to thicken other proofs / That do demonstrate thinly.” How much does it thicken the other proofs? Let’s find out. We can throw some numbers figures into Bayes’ theorem, and it will tell us, in percent, how certain Othello is after he sees Cassio with the napkin.

We start off with what is called the prior probability. That is the initial probability before he receive new information. Now, before the test of the handkerchief, Othello says:

Othello. By the world,
I think my wife be honest, and think she is not,
I think that thou [meaning Iago] art just, and think thou are not.

It seems that he views the odds that he has been cuckolded as 50:50. His mind is evenly divided. So, we enter this into the formula.

Next, we need to come up with a probability value that represents the chance that Cassio has the handkerchief given that Othello has been cuckolded. The dialogue between Othello and Iago suggests that we should assign a high percentage to this figure, which, while not 100%, must approach 100%. Call it 90%. We enter this into the formula.

The final probability value we require is the chance that Cassio should have his handkerchief given that Othello has not been cuckolded. Although Iago suggests that lovers give away their tokens all the time, Othello’s reaction suggests he strongly disagrees. So, we can call the likelihood that Cassio has the napkin and nothing untoward has happened something low, in the order of magnitude of say 1%.

We plug all these values into Bayes’ theorem, and it gives us an answer: if Othello’s mind had been evenly divided on Desdemona’s guilt, once he sees the handkerchief in Cassio’s hand, he can be 98.9% certain that he has been cuckolded. So, it would appear, contrary to Rymer, that the “Jealousie was Tragical because the proof is Mathematical.” A certainty test of 98.9% is certainly high. Modern statisticians use a 5% certainty test to establish moral certainty, or, the threshold at which one has the right to act. Othello is well within this 5% range.

We can also play with the numbers to arrive at different results. Some might say, for example, that a 50% initial probability that he is a cuckold is way too low. Look, if your best friend—who is known for honesty—and your wife’s father himself is telling you to watch out, then the initial probability you are a cuckold is likelier closer to 80%. If this is the case, then, after the napkin test, the chances you are a cuckold go up from 98.9 to 99.7%. That’s equivalent to the three-sigma test that physicists, up to recently, use to confirm that their experiments are the real deal, and not an artifact of chance. 99.7% is quite confidence inspiring, and shows that Othello, after seeing the napkin, could be quite sure.

Of course, everyone says Othello was too rash. He should not have killed Desdemona. I get this. But then, should he have killed Iago? Remember, the play is set up so that he has to kill someone, whether Desdemona or Iago. This is where probability gets interesting. The question the play asks is: how high a degree of confidence must we have to act? Those who contend Othello achieved moral certainty also have to contend with the fact that he was wrong. Those who contend that Othello failed to achieve moral certainty have to wonder how today’s insurance, medical, and consumer safety industries—not to mention courts—often hang matter of life and death on less stringent significance tests.

The intersection between probability theory and theatre is one of the richest crossroads in research today. Not only can we talk about whether Othello should or shouldn’t have acted, we can compare Othello to, say Hamlet. Hamlet is told by the ghost that his uncle killed his dad. As Hamlet himself realizes, the ghost is much less trustworthy than a best friend. Next, just like in Othello, Hamlet stages the mousetrap, the play within the play, to determine, on a probabilistic basis, whether his uncle is guilty. Like the test of the napkin, Hamlet’s mousetrap isn’t perfect. But for some reason, we allow Hamlet to act. Why is that? These are all fascinating questions that arise when we examine theatre from the perspective of probability theory.

I’ve always believed that theory should service practice. How can probability theory add to the performance of drama? I saw an Othello this year, a fast-paced one, big-budget production. But watching it, I felt some lines were missing. It turns out, after checking the text, parts of the text were missing: the beginning of act one, scene three where the sailor gives conflicting accounts of the size and heading of the attacking Turkish fleet. I learned later that this section is quite often omitted from performances. What a shame: the scene illustrates how, so often in the most critical affairs, though we want certainty, we must act based on probability. This moment sets the scene for the entire play: Othello too wants certainty, but must act on probability. By bringing science to the theatre, I offer a powerful reason for including this scene in future productions: this scene unlocks the play.

If you would like learn more about chance in theatre, pick up a copy of my book: The Risk Theatre Model of Tragedy: Gambling, Drama, and the Unexpected, published by Friesen in 2019. This talk is based on a new book chapter that came out a few months ago called: “Faces of Chance in Shakespeare’s Tragedies: Othello’s Handkerchief and Macbeth’s Moving Grove.” It’s in a book called: Critical Insights: Othello, edited by Robert C. Evans and published by Salem Press. Follow me on Twitter @TheoryOfTragedy.

Thank you.


P(C) initial probability Othello is a cuckold 50%
P(~C) initial probability Othello is not a cuckold 50%
P(H C) chance Cassio has the handkerchief if Othello is a cuckold 90%
P(H ∣ ~C) chance Cassio has the handkerchief if Othello is not a cuckold 1%

                                                               P(H ∣ C)
P(C H) = P(C) * _____________________________________________________________

                                          {P(H ∣ C) * P(C)} + {P(H ∣ ~C) * P(~C)}

Putting it all together yields this result:

0.989 = (0.50) * _____________________________________________________________

                                          {0.90 * 0.50} + {0.01 * 0.50}

– – –

Don’t forget me. I’m Edwin Wong and I do Melpomene’s work.
sine memoria nihil

Dear Publisher: Please Publish My Book WHEN LIFE GIVES YOU RISK, MAKE RISK THEATRE

Risk Theatre Performing Arts Book Proposal

Four years ago, seventeen publishers shut the door on my book The Risk Theatre Model of Tragedy: Gambling, Drama, and the Unexpected. After a year of aporia, FriesenPress, the self-publishing arm of the printing behemoth Friesens Corporation, released it. Today, my second book, When Life Gives You Risk, Make Risk Theatre: Three Plays and Five Essays, is coming together. Let’s give the traditional publishers a knock on the door. Maybe the gatekeepers will be more receptive this time. This time, things are different. Before, risk theatre was unknown and untested. Now risk theatre is going from peak to peak. The name of the game is to keep going. Never stop.

Here’s the template of the pitch letter. It’s short (326 words). It gives them a reason to be excited (who doesn’t like a new arts movement?). It builds upon the successes of the previous book (it was a terrific stroke of luck for my little self-published book to get two glowing reviews in peer-reviewed theatre journals). Will it be enough?– Please…

Dear Publisher,

I curate The Risk Theatre Modern Tragedy Playwriting Competition, the world’s largest competition for the writing of tragedy ( The competition, now in its fourth year, is based on my self-published book: The Risk Theatre Model of Tragedy (2019). It presents a new theory of drama by arguing that downside risk is the dramatic fulcrum of the action in tragedy. Hundreds of playwrights (from sixteen countries, including some former Soviet republics) have entered the competition and the book has sold over 2700 copies. In the last two years, I have been invited to talk about risk theatre at the Kennedy Center, the National New Play Network, Working Title Playwrights (Atlanta), the Society of Classical Studies, the Classical Association of the Middle West and South, Marionet Teatro (Portugal), as well as many universities and theatres. Risk theatre is an exciting and growing twenty-first century arts movement.

To commemorate the fourth year of the playwriting competition, I have put together a compilation called: When Life Gives You Risk, Make Risk Theatre: Three Plays and Five Essays. Three finalist and winning playwrights have agreed to have their plays published. In addition, they will contribute new introductory essays discussing the significance of risk. The second half of the compilation consists of five essays I wrote applying risk theatre to the interpretation of plays from Aeschylus to Arthur Miller as well as to the novel.

Risk theatre is changing the way people look at the dramatic art form of tragedy. Would you be interested in participating in this exciting, bold, and important arts movement by publishing When Life Gives You Risk, Make Risk Theatre: Three Plays and Five Essays?

Attached are reviews of my first book from the peer-reviewed journals Theatre History Studies and NJ Drama Australia Journal. You may also see enthusiastic customer reviews of my first book at Goodreads and Amazon (links below).

Don’t hesitate to ask if you have any questions. I look forward to hearing from you.

All best,

Edwin Wong

NJ Drama Australia The Risk Theatre Model of Tragedy Gambling Drama and the Unexpected

– – –

Don’t forget me, I’m Edwin Wong and I do Melpomene’s work
sine memoria nihil


Stats, stats, stats!

IT’S A WRAP! THANK YOU, assiduous playwrights, for entering! The 2021 competition is closed to entries ( Your scripts are being carefully read by professional jurors (who will remain anonymous until they determine the grand prize winner late August). Stay tuned for the grand opening of the 4th annual 2022 competition–an announcement will come soon.

This year, 122 plays have come in from 3 continents (Europe, Oceania, and North American) and 4 countries (USA, Australia, Canada, and UK). Here are the country breakouts:

USA 101

Australia 2

Canada 14

UK 5

Of the American entries, 73 are from the east and 28 are from the west. Of the entries from the east, 22 are from New York and 14 from Los Angeles. Go New York and Los Angeles!

The breakdown between male and female entrants stands at 75 men and 47 women. Prior to the twentieth century, I only know of a handful of female tragedians: Elizabeth Cary (The Tragedy of Mariam the Fair Queen of Jewry, 1613), Hannah More (Percy, 1777), and Joanna Baillie (various plays and a theory of tragedy based on the emotions, nineteenth century). Thank you to assiduous reader Alex for writing in about More and Baillie.

Last month the website averaged 43 hits a day. The top 3 countries clicking were: US, Canada, and UK. Most clicks in a day was 287 on August 15, 2020 when we announced the 2020 winner: THE VALUE by Nicholas Dunn. Best month was March 2019 with 2372 when we announced the 2019 winner: IN BLOOM by Gabriel Jason Dean. All time views stand at 27,520 and growing. So far, so good for this grassroots competition!

My award-winning book, eBook, and audiobook (narrated by Coronation Street star Greg Patmore) THE RISK THEATRE MODEL OF TRAGEDY: GAMBLING, DRAMA, AND THE UNEXPECTED hit the bookshelves in February 2019 and has sold 2680 copies. A shout out to everyone for their support—all proceeds fund the competition. The book is a winner in the Readers’ Favorite, CIPA EVVY, National Indie Excellence, and Reader Views literary awards as well as a finalist in the Wishing Shelf award.

Please ask your local library to carry this exciting title. To date, the book can be found at these fantastic libraries: LA Public, Bibliothèque national de France, Russian State Library, Herzog August Bibliothek Wolfenbüttel, Senate House Library (London), Universitätbibliothek der Eberhard Karls (Tübingen), Brown University, CalArts, Palatine Public, Pasadena Public, Fargo Public, South Texas College, University of Bristol, University of Victoria, Greater Victoria Public, Richmond Public, Smithers Public, University of Colorado, Denver Public, McMaster University, Buffalo and Erie County Public, Rochester Public, Wheaton College, South Cowichan Public, Vancouver Public, Hillside Public (Hyde Park, NY), Scarsdale Public (NY), Indianapolis Public, Okanagan College, Concordia University, University of British Columbia (UBC), University of London, Wellesley Free, Tigard Public, Herrick Memorial, Gannett-Tripp, Charles J. Meder, Westchester College, Cambridge University, Fordham University, SUNY Cortland Memorial, SUNY New Paltz, SUNY Binghamton, Glendale Public, Benicia Public, Santa Clara County Public, Glendora Public, Cupertino Public, Milpitas Public, St. Francis College, Noreen Reale Falcone Library, Southern Utah University, Daniel Burke, Manhattan College, Humboldt County Public, Santa Ana Public, Azusa Pacific University, Biola University, CUNY, Westchester Community, University of Utah. Let’s get a few more libraries on board! Reviews of the book can be found here:

Edwin Wong on Risk and Tragedy: The Literary Power of High-Stakes Gambles, One-in-a-Million Chances, and Extreme Losses

Here are links to YouTube videos of me talking about risk theatre at NNPN and CAMWS panels:

Don’t forget me, I’m Edwin Wong and I do Melpomene’s work.
sine memoria nihil