Ontology of naive realism (Lyons 1977, ch. 11.3)
order definition examples properties
1 entities that are said to exist physical objects: persons, animals, things relatively constant as to their perceptual properties; located in space and time; publicly observable
2 entities that are said to occur / to take place events, processes, states-of-affairs located in time
3 entities that form the object of propositional attitudes abstract entities: propositions, concepts have no spatio-temporal location