Kant’s held we can discover categories of the human understanding, the basis for any possible cognition of phenomena. These categories are not intrinsic sub-divisions of reality itself, but those governing “our” conceptual schema:
- Inherence and Subsistence (substance and accident)
- Causality and Dependence (cause and effect)
- Community (reciprocity)
The categories are presented as forming a single exhaustive list, with the four classes of categories imposing four different forms of unity on the object known (Paton 1936, 295–9).
Although these are categories of the understanding, they nonetheless retain a certain sort of ontological import, as it is a priori that they apply universally to all objects of possible cognition (A79/B105).