Pulitzer Prize-winning American playwright and novelist Thornton Wilder (1897–1975) believed that there were four foundational elements that separate drama from other arts:

These conditions are:

1) The theatre is an art which reposes upon the art of many collaborators;

2) It is addressed to the group-mind;

3) It is based upon a pretense and its very nature calls out a multiplication of pretenses;

4) Its action takes place in a perpetual present time. (From Playwrights On Playwriting, Edited by Toby Cole, Hill and Wang, New York, 1983)

No one doubts that a theatrical production is a collaborative art involving the efforts of playwrights, actors, directors, producers, designers, carpenters, painters, stagehands, and everyone else who works together on the performance of a play. It's remarkable that all of the divergent and sometimes incompatible personalities involved manage to put aside their differences and pool their resources for the common goal of presenting a play.

The dramatist through working in the theatre gradually learns not merely to take account of the presence of the collaborators, but to derive advantage from them; and he learns, above all, to organize the play in such a way that its strength lies not in appearances beyond his control, but in the succession of events and in the unfolding of an idea, in narration.

Of all the collaborators on a theatrical production, Wilder singles out the actor as a "chief collaborator."

The actor’s gift is a combination of three separate faculties :

1) An observant and analyzing eye for all modes of behavior about us, for dress and manner, and for the signs of thought and emotion in one’s self and in others.

2) The strength of imagination and memory whereby the actor may, at the indication in the author’s text, explore his store of observation and represent the details of appearance and the intensity of the emotions — joy, fear, surprise, grief, love, and hatred, and through imagination extend them to intenser degrees and to differing characterizations.

3) A physical co-ordination whereby the force of these inner realizations may be communicated to voice, face, and body.

Wilder believes that a dramatist should provide characters in a play that "will take advantage of the actor’s gift."

By "group-mind," Wilder means that the presentation of a play "presupposes a crowd." In other words, a play requires an audience. In fact, any actor will insist that performing a play without an audience is futile and even demeaning to themselves, their art, and to the art of the playwright.

In Rosencrantz and Guildenstern Are Dead, written by Tom Stoppard, Rosencrantz and Guildenstern, the characters from Shakespeare's Hamlet meet a group of travelling actors on the road to Elsinore Castle, and the actors offer to perform for them. Rosencrantz and Guildenstern wander away during their performance and continue on their way to the Elsinore.

When Rosencrantz and Guildenstern later meet the players at Elsinore, the leader of the players confronts them.

PLAYER. (Bitterly.) You left us.... We can't look each other in the face! You don't understand the humiliation of it—to be tricked out of a single assumption, which makes our existence viable—that somebody is watching... We ransomed our dignity to the clouds, and the uncomprehending birds listened. Don't you see?! We're actors—we're the opposite of people! (Rosencrantz and Guildenstern Are Dead, Act 2)

Wilder's third element of drama is that it's a pretense made up of multiple pretenses, but these pretenses are readily accepted by everyone involved in a theatrical production, including the audience.

The theatre is a world of pretense. It lives by conventions: a convention is an agreed-upon falsehood, a permitted lie . . . The stage is fundamental pretense and it thrives on the acceptance of that fact and in the multiplication of additional pretenses. When it tries to assert that the personages in the action “really are,” really inhabit such and such rooms, really suffer such and such emotions, it loses rather than gains credibility.

Wilder's classic drama Our Town is a perfect example of the third principle. The play is clearly a pretense. It's a play and nothing more.

Wilder's stage directions set the scene and the context of the play.

No curtain.

No scenery.

The audience, arriving, sees an empty stage in half-tight.

Presently the STAGE MANAGER, hat on and pipe in mouth, enters and begins placing a table and three chairs downstage left and a table and three chairs downstage right....As the house lights go down he has finished setting the stage and leaning against the right proscenium pillar watches the late arrivals in the audience.

When the auditorium is in complete darkness, he speaks:

STAGE MANAGER. This play is called "Our Town." ... (Act 1)

Throughout the play, the Stage Manager comments on the action and the characters, and to a certain extent he controls what the audience sees, sometimes cutting scenes short, or moving the action ahead in time.

Our Town seems to defy one of Aristotle's major precepts.

Of all plots and actions the epeisodic are the worst. I call a plot 'epeisodic' in which the episodes or acts succeed one another without probable or necessary sequence. Bad poets compose such pieces by their own fault, good poets, to please the players; for, as they write show pieces for competition, they stretch the plot beyond its capacity, and are often forced to break the natural continuity. (Poetics, Part IX)

Our Town is entirely episodic. The play is composed of a series of episodes or vignettes representing selected moments in the lives of characters who represent the people who live in Grover's Corners, New Hampshire.

Wilder is not a "bad poet," however, and the episodic nature of Our Town emphasizes rather than diminishes the action of the play—its "natural continuity"—and contributes to the emotional impact of the play as a whole.

The scenes in Our Town represent moments in the lives of the characters between the years of 1901 and 1913. What the audience sees, however, is happening right here and right now, moment by moment, in what Wilder calls a "perpetual present time."

This is what gives the performance of a play its immediacy and its heightened emotional effect on the audience.