ABSTRACT
Uchronias (also known as alternate histories, alternative histories, or allohistories) are works of fiction that emerge from the difference between an established narrative timeline and a "what-if" scenario: if a given event is assumed to have gone differently, then the change in that event has repercussions for the flow of time beyond the point of divergence. In the structural view of world-building, counterfactual thinking crystallizes into the allohistorical conceit (AC), a recurring storytelling and world-building trope with wide-ranging implications for the entirety of the imagined world. In this chapter, the author maps and exemplifies allohistorical practices and the various contextual nexuses that inform their production and reception: historical rigor and the complications of contemporary historiography; scientific discourse and the narrativization of mathematical abstractions in the wider culture; industrial practices, culture, and genre; and medium specificity and the affordances of new media. The chapter reveals the overlapping structures that determine the meanings, styles, and practical applications of the AC.
