| Class Summary | 
| Concrete Individual |  | 
| Endurant | Endurants are said to be wholly present whenever they are present, i.e., they are in time, in the sense that if we say that in circumstance c1 an endurant e has a property P1 and in circumstance c2 the property P2 (possibly incompatible with P1), it is the very same endurant e that we refer to in each of these situations. | 
| Endurant Universal |  | 
| Formal Relation |  | 
| Monadic Universal |  | 
| Object | Objects are Substantials with a well-defined identity. | 
| Quale | Quales are perceptions or conceptions of an intrinsic moment that can be represented as a point in a quality structure. | 
| Quality Structure | An attempt to model the relation between intrinsic moments and their representation
in human cognitive structures is presented in the theory of conceptual spaces. | 
| Situation | Situations are special types of endurants. |