 We come to know ontological categories through the objects that we come to know. However, our knowledge of ontological categories is even more provisional than our knowledge of objects. The difference between knowing objects and knowing categories explains why ontological categories are often confused with concepts. The problem is that categories do not allow direct acquaintance as objects do. Concepts are names of ontological categories, which implies that concepts are partial, static, separate representations of items that in themselves are both essentially dynamic and inseparable from other ontological categories. Like the knowledge of objects, the knowledge of ontological categories also changes—when ontology develops, our understanding of ontological categories develops as well, so that we gain a deeper and better grasp of their articulation and subtleties. Some categories have countless variations, others only a few minor ones. The most general and schematic categories are those with the most meager content, and they are therefore those that change least (A27b).