Even a bit of historical perspective makes this question more complex.
For twenty-five centuries people have written works that we call
literature today, but the modern sense of literature is scarcely two
centuries old. Prior to 1800 literature and analogous terms in other
European languages meant ‘writings’ or ‘book knowledge’. Even today,
a scientist who says ‘the literature on evolution is immense’ means not
that many poems and novels treat the topic but that much has been
written about it. And works that today are studied as literature in
English or Latin classes in schools and universities were once treated not
as a special kind of writing but as fine examples of the use of language
and rhetoric. They were instances of a larger category of exemplary
practices of writing and thinking, which included speeches, sermons,
history, and philosophy. Students were not asked to interpret them,
as we now interpret literary works, seeking to explain what they are
‘really about’. On the contrary, students memorized them, studied
their grammar, identified their rhetorical figures and their structures
or procedures of argument. A work such as Virgil’s Aeneid, which today
is studied as literature, was treated very differently in schools prior to
1850.