These models constitute a central portion of a general project to develop a process model of mental phenomena. Specific forms of categorial and existential dependence exist among these strata. Hypothesising forms of existential dependence does not entail resorting to more or less overt hypotheses of reductionism. Each stratum has its own principles, laws and categories. The dependence relationship among strata tells us that there are never minds without material bearers, and that there are never social phenomena without material and mental bearers.
Specific relations organize the various layers distinguishable internally to each stratum.
The forms assumed by these relations are specific to each stratum and cannot be ingenuously generalized. 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.