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