 To deal with these and other hard cases, Friend recommends against trying to find necessary and sufficient conditions for being a work of fiction, although not by relinquishing the emphasis on works in favor of more basic units like fictional statements and narratives. Instead, fiction and non-fiction should be regarded as very broad genres in which particular works are embedded, where a genre is a way of classifying representations that guides appreciation. Borrowing from ideas in Walton’s “Categories of Art” (Walton 1970), Friend argues that classifying a work as a work of fiction or non-fiction depends on a range of features. A feature is standard for a genre if possession of the feature tends to place the work in that genre; contra-standard if possession tends to exclude the work from the genre. (Features are variable if works can have or lack them without this affecting membership in the genre, such as the number of chapters a work contains). Thus, containing made-up material counts as standard for the genre of fiction but contra-standard for non-fiction, while being faithful to the facts counts as standard for non-fiction but contra-standard for fiction. (As Friend notes, such a classification may itself change over time; the kind of inventive embellishment found in Tacitus’s Histories, for example, was once regarded as standard for historical non-fiction, but is now regarded as contra-standard [Friend 2012: 192–3].) 