天外救星

Deus ex machina is a plot device whereby a seemingly unsolvable problem is suddenly and abruptly resolved by the contrived and unexpected intervention of some new event, character, ability or object. Depending on how it is done, it can be intended to move the story forward when the writer has “painted himself into a corner” and sees no other way out, to surprise the audience, to bring the tale to a happy ending, or as a comedic device.
  
Origin of the expression

The Latin phrase deus ex machina, from deus, meaning “a god”, ex, meaning “from”, and machina, meaning “a device, a scaffolding, an artifice”, is a calque from Greek ἀπὸ μηχανῆς θεός (apò mēkhanḗs theós), meaning “god from the machine”. Such a device was referred to by Horace in his Ars Poetica (lines 191–2), where he instructs poets that they should never resort to a “god from the machine” to resolve their plots “unless a difficulty worthy a god’s unraveling should happen”. He was referring to the conventions of Greek tragedy, where a machine is used to bring actors playing gods onto the stage. The machine could be either a crane (mechane) used to lower actors from above or a riser that brought actors up through a trapdoor.

Ancient usage

Aristotle criticized the device in his Poetics, where he argued that the resolution of a plot must arise internally, following from previous action of the play …

In modern literature

A deus ex machina is generally deemed undesirable in writing and often implies a lack of creativity on the part of the author. The reasons for this are that it does not pay due regard to the story’s internal logic (although it is sometimes deliberately used to do this) and is often so unlikely that it challenges suspension of disbelief, allowing the author to conclude the story with an unlikely, though perhaps more palatable, ending. Following Aristotle, Renaissance critics continued to view the deus ex machina as an inept plot device, …

— Wikipedia on Deus ex machina

2014.07.11 Friday ACHK