The mental and social strata exhibit mechanisms which are much more intricate than those that operate in the material stratum. In the case of the social stratum, the various layers constitute a community of contexts with numerous complex relations of dependence and reciprocal influence. Description of the strata and layers of reality intersects with description of the objects of which it is composed. For example, no individual possesses complete and absolute mastery of his or her mother tongue. The intersecting of the description of strata and layers with the description of objects further explains why we need different sets of categories.
Ontology studies the laws of dependence among different levels.
This relationship of transformation is that which inheres, for example, in the passage from the inanimate material world to the animate material world. The categories of the former maintain their validity also for the second, but in a different form which reflects the specificity of the new level. The stratified organization of reality should not be confused with the problem of the parts of a whole, and whether all the parts of a whole are of the same nature as the whole. But the levels of an object are not parts of the whole.