What is a Deus Ex Machina?
A plot device where a seemingly unsolvable problem is suddenly resolved by an unexpected and contrived intervention.
The Divine Intervention of Deus Ex Machina
Deus ex machina is a plot device where a seemingly unsolvable problem is suddenly resolved by an unexpected and contrived intervention. This intervention is typically performed by a god, deity, or some other higher power--the machina in the name refers to a machine, indicating something outside the realm of humanity. Through the use of deus ex machina writers can introduce a twist in their story that may surprise and delight readers.
While deus ex machina is a useful tool for writers, it should be used with caution. Its sudden and seemingly arbitrary nature can have the opposite effect, leaving the readers feeling cheated or unsatisfied with the resolution of the story. A good use of deus ex machina occurs when the intervention is a plausible part of the story that has been subtly set up earlier in the text, making the readers feel that the solution is earned rather than arbitrary.
Deus ex machina has a long history in literature. Here are two examples of how this plot device has been used to both positive and negative effect.
In Homer's The Odyssey, Athena acts as a deus ex machina when she intervenes in the story to save Odysseus and his son Telemachus from being killed by the suitors who have taken over the palace of Ithaca. Athena provides an intervention that is both plausible and earned, as she is shown earlier in the text to be a protector of Odysseus and has intervened in the story several times before.
H.G. Wells' War of the Worlds is a classic example of the negative effects of deus ex machina. The story builds up tension as humanity struggles to fight the Martian invaders, only to have the threat suddenly ended by the unexpected death of the Martians due to a common pathogen. This intervention is not plausible or earned, and readers can feel cheated by this seemingly arbitrary ending.