The answer is infinite storytelling. The main accord of this story is doted to creating a spatial metaphor for time. In other words, the writer is trying to take an abstract, non-visual idea – time – and make a visual model for it. Literally, that's what "the garden of forking paths" means. It's a metaphor, or model, to aid us to contemplate the infinitely diverging, spreading network that Ts'ui Pen imagines time to be. The argument of the infinite is another major theme in Borges' work.
