That a play has one central action which is its formal cause is the most influential interpretative idea to emerge among theatre writers since the old model of situation/incident/complication/climax/denouement. Unfortunately, the action concept has been insufficiently developed, excessive hopes have been pinned on it, and it has become a reductive threat. One way of properly handling the concept of action is to consider the definition of the action of a play as the "master psychic event" of the play. In this way, the play is seen to exist only as mental events in the audience and as sign-potentials of the playscript. The play does not have an action, but is perceived as being an action. The interpreters of plays, variously the actors and directors, do not observe the actions but invent them. As part of the process of reducing the ambiguity of specific signs to be seen by the audience, these interpreters test possible syntheses of individual perceptions into a functionally integrated structure of meaning. There need not be only one response to a play's action, even at the conceptual level of master event. Because it operates at a level "close to the script," constant reference to the play as an action tends to serve as a corrective on more abstract levels of meaning. (RL)