an extension of possibilities into the future
Original Dramatica® Definition
Speculation is the effort to determine what could conceivably happen in the future even though it is not the most likely scenario. Speculation leads a character to expect the unlikely in the event that it actually occurs. Difficulties arise when Speculation runs rampant and a character puts effort into preparing for things that are so unlikely as to be unreasonably improbable.
syn. prognostication, surmising possibilities, conjecturing