“The Garden of Forking Paths” is a neat and clever detective story, but it also includes a theme of which Borges was very fond: the notion of multiple possibilities of an action. In science fiction, a whole subgenre of stories has been written to speculate on multiple universes arising from different choices in crucial situations: What would the present be like, for example, if the South had won the Civil War? This is the sort of story that Ts’ui Pen wrote, yet his story included not only an unexpected outcome but also multiple possible outcomes of various actions. The idea so fascinated Borges that he wrote another short piece, “Examen de la obra de Herbert Quain” (“An Examination of the Work of Herbert Quain”); the mythical Quain wrote novels like Ts’ui Pen’s. A single first chapter is followed by three second chapters, among which the reader may choose. Each of those second chapters is followed by three possible third chapters, and so on.
As Albert says in the story, people, with their attention fixed on their memory of the past and their limited perception of the future, tend to think of time as a single strand of reality, with all the unrealized events and all the unchosen alternatives only possibilities. This fascination with the theme of multiple universes marks many of Borges’s works.