It is a difficult task drawing a suitable point of demarcation that divides fiction from nonfiction. In this essay, I explore various definitions of ‘fiction’, establishing two senses of the term: fiction as prompting imagination, and fiction as not real. I suggest the two senses are erroneously conflated, and are mutually exclusive. I then argue that all engagements with sensible things in the world prompt an imagination of possible worlds, but this does not necessarily entail fictionality in the ‘not real’ sense. A basic shaping of the process of understanding is then drawn: all understanding involves narrative posits. Even seemingly ‘real’ imaginings are never perfectly veridical; they are verisimilar at best.