It is a futile enterprise to categorize and compartmentalize an artist's work according to any criteria, whether one is working within the artist's personal oeuvre, or within the collected works of a school or movement...Curation is in many ways a form of narrative, which allows one to create an arc, a frame around the works being shown. That's difficult enough, and to separate anything into A, B, and C requires a reductive, often damaging approach, especially in art. There will always be works that straddle the designations, and even those that fit neatly into one category or another remain singular, and such grouping threatens to marginalize the work in the viewers' minds.
Still, for the sake of introducing works to an audience, whether or not that audience knows how to observe and appreciate art, such cogent organization is necessary. It then remains up to the individual viewer to use this scaffolding to build a larger perspective, or to tear it to the ground and start afresh.
T.s. Flock, "On History and Curation"