On "three" in drama
Many of Stephen Jeffreys' (2019) maxims are in threes; indeed, three is a number of great structural significance in many disciplines.
Perhaps we can understand why three is such a prevalent feature of dramatic construction by following the stages of a magic trick:
- The pledge
- The turn
- The prestige
In this case, two is not enough, because we expect change. We're used to thinking of ordinary life in binary terms; I think a very basic tendency one falls back on is whether something is like what one is used to or what is not used to: the familiar and unfamiliar. Indeed, the Three Act Structure borne out of Joseph Campbell's work on the "Monomyth" seems at first to be binary: a journey from the familiar to the unfamiliar. But it's not binary: it's triadic. The hero goes back home again, but have fundamentally changed and so home is not the home it was. If a person changes, so does the way they see everything; this then changes the way that we, the audience, see everything, too. The familiar, when returned to, is actually even less familiar than the unfamiliar. That's the prestige. And that's what makes a good ending.
References
Jeffreys, Stephen. 2019. Playwriting: Structure, Character, How and What to Write.
Old-fashioned magic tricks are also in three acts. The first act is called ‘the pledge’, in which, for example, I show you an ordinary pen and pledge this is just a pen and hand it around for audience members to inspect. The second act is called ‘the turn’, where I turn the pen into a seagull and it flies out of the window: the object has become something else. But that’s not enough for the trick. The third act is called ‘the prestige’, which is the real formative trick, where I make the seagull fly back to me and turn it back into a pen. (Page 48)
Campbell. The Hero With A Thousand Faces