Edwin Booth as Hamlet.

“To be or not to be,” asks Hamlet. But to whom is he speaking?

Let’s say you’re directing Hamlet’s famous soliloquy. An entire production can hang on another question: Does your actor speak only to himself, or does he address the audience? Ay, there’s the historical rub.

As a dramatic technique, the soliloquy is a brilliant way of breaking through the surface: the character presents himself to himself. It’s at once private and, since it’s spoken out loud in a theater, as public as a bullhorn.

A soliloquy is not a monologue; that’s where one character shares usually personal information with another, often in an aside.

Ancient Greek tragedy and Old Comedy have soliloquies, but they’re usually brief and addressed to the audience. It isn’t until the Renaissance that they dig deep.

Hamlet has several, of course. Another, justly famous: in Marlowe’s Dr. Faustus, the overreaching doctor’s pact with the devil — 24 years of pleasure and power — is up. He has an hour to live. Marlowe gives him 60 lines, one per minute, to face the fact of “eternal damnation.”

But is Faustus speaking just to himself, or should the actor break the fourth wall and address the audience?

If Hamlet (or Faustus) talks only to himself, he is existentially alone.

He’s doing a mental improvisation to find ways of coping with a world gone instantly mad: a death, possibly murder, a hasty marriage, and now a grisly specter floating around the ramparts and claiming to be his father.

If the actor addresses the audience, Hamlet goes beyond the world of the play. In the conventions of theater, he’s alone onstage, sure. But there’s breathing warmth close at hand. If he talks to them he has allies and, though helpless, a support group.

Some directors like the connection with the audience. It can coax spectators into a group experience. Others, Peter Brook among them, seal Hamlet off. He’s alone. It’s like over-hearing someone pray. In his book, Shakespeare and the History of Soliloquies (which costs near a month’s rent) James Hirsh exhaustively studies the technique. He offers a third possibility: Hamlet’s “to be or not” is a “feigned soliloquy.” He wants to be overheard by Claudius and Polonius (are they nearby?). His riff on life and death, in other words, is a calculated fiction.

So, to share or not to share in-most thoughts and fears with the audience? Maybe we can get some help from the past.

St. Augustine (354-430 CE) coined the term. Some ancient philosophers, Plato among them, wrote in dialogue form. Augustine wanted an inner dialogue, not between two people, but between himself and Reason. In order to “lay bare what I am,” he combined the Latin solus (sole) with loqui (to speak) and entitled a treatise Liber Soliloquiorum (book of soliloquies). The book offered “little reasonings about the soul.”

He also uses the technique in his masterwork, Confessions. Written in the form of an improvised prayer, it reads like an extended soliloquy.

Augustine writes his confession for a definite audience of his followers. But he never addresses them. In effect, he is alone with his Creator.

And he composed ad lib — no corrections, no pauses to polish a phrase or insert a sharper example. He invented as he went along: no rehearsals, map, or outline, no fixed end in sight.

“The Confessions contain nothing which can be diagnosed as an update,” writes biographer Robin Lane Fox. “Augustine was a trained improviser, one whose skills should not be underestimated.”

He never looked back. But was he alone, existentially alone, when he soliloquized his text?

Actually, no. According to Fox, Augustine dictated his “prayer in progress” to secretaries adept in shorthand. The “creation” was public from the start.

So, directors of Hamlet: “to share or not to share”? That is the dramaturgical question.