Is Something a Class or an Instance?
- Something should be a class if it could have instances
- Something should be an instance if it is clearly a single member of the set defined by a class
Film
- Class; instances are individual films.
Reel of Film:
- Class; instances are physical reels
Film reel with serial number SW19876
Science Fiction
- Instance of the class Genre.
Science Fiction Film
- Class; instances include ‘Star Wars’
Showing of ‘Star Wars’ in the Phoenix Cinema at 7 p.m.:
- Instance of ShowingOfFilm