module sensing
  depends on creating

  sort declarations
    sense :: create
    hear :: sense
    read :: sense
    see :: sense

    energy :: tangible_entity
    sound :: energy
    light :: energy

    physical_object :: tangible_entity
    inanimate_object :: physical_object
    artifact :: inanimate_object
    physical_document :: artifact

  axioms 
    false if instance(X, sense),
             -defined_object(X).

    false if instance(X, sense),
             object(X, O),
             -instance(O, tangible_entity).

    false if instance(X, sense),
             -defined_experiencer(X).

    false if instance(X, sense),
             experiencer(X, E),
             -instance(E, tangible_entity).

    false if instance(X, sense),
             result(X, R),
             -instance(R, message).

    agent(X, Y) if instance(X, sense),
                   experiencer(X, Y).


    false if instance(X, hear),
             object(X, O),
             -instance(O, sound).


    false if instance(X, read),
             object(X, O),
             -instance(O, physical_document).


    false if instance(X, see),
             object(X, O),
             -instance(O, light).